Richard P. Usatine, MD

THE COMPARISON

A A 27-year-old Hispanic woman with comedonal and inflammatory acne. Erythema is prominent around the inflammatory lesions. Note the pustule on the cheek surrounded by pink color.

B A teenaged Black boy with acne papules and pustules on the face. There are comedones, hyperpigmented macules, and pustules on the cheek.

C A teenaged Black girl with pomade acne. The patient used various hair care products, which obstructed the pilosebaceous units on the forehead.

Epidemiology

Acne is a leading dermatologic condition in individuals with skin of color in the United States.¹

Key clinical features in people with darker skin tones include:

• erythematous or hyperpigmented papules or comedones
• hyperpigmented macules and postinflammatory hyperpigmentation (PIH)
• increased risk for keloidal scars.²

Worth noting

• Patients with darker skin tones may be more concerned with the dark marks (also referred to as scars or manchas in Spanish) than the acne itself. This PIH may be viewed by patients as the major problem.
• Acne medications such as azelaic acid and some retinoids (when applied appropriately) can treat both acne and PIH.³
• Irritation from topical acne medications, including retinoid dermatitis, may lead to more PIH. Using noncomedogenic moisturizers and applying medication appropriately (ie, a pea-sized amount of topical retinoid per application) may help limit irritation.^4,5
• One type of acne seen more commonly, although not exclusively, in Black patients is pomade acne, which principally appears on the forehead and is associated with use of hair care and styling products (FIGURE C).

Health disparity highlight

Disparities in access to health care exist for those with dermatologic concerns. According to one study, African American (28.5%) and Hispanic patients (23.9%) were less likely to be seen by a dermatologist solely for the diagnosis of a dermatologic condition compared to Asian and Pacific Islander patients (36.7%) or White patients (43.2%).¹ Noting that isotretinoin is the most potent systemic therapy for severe cystic acne vulgaris, Bell et al⁶ reported that Black patients had lower odds of receiving isotretinoin compared to White patients. Hispanic patients had lower odds of receiving a topical retinoid, tretinoin, than non-Hispanic patients.⁶

THE COMPARISON

A A 27-year-old Hispanic woman with comedonal and inflammatory acne. Erythema is prominent around the inflammatory lesions. Note the pustule on the cheek surrounded by pink color.

B A teenaged Black boy with acne papules and pustules on the face. There are comedones, hyperpigmented macules, and pustules on the cheek.

C A teenaged Black girl with pomade acne. The patient used various hair care products, which obstructed the pilosebaceous units on the forehead.

Epidemiology

Acne is a leading dermatologic condition in individuals with skin of color in the United States.¹

Key clinical features in people with darker skin tones include:

• erythematous or hyperpigmented papules or comedones
• hyperpigmented macules and postinflammatory hyperpigmentation (PIH)
• increased risk for keloidal scars.²

Worth noting

• Patients with darker skin tones may be more concerned with the dark marks (also referred to as scars or manchas in Spanish) than the acne itself. This PIH may be viewed by patients as the major problem.
• Acne medications such as azelaic acid and some retinoids (when applied appropriately) can treat both acne and PIH.³
• Irritation from topical acne medications, including retinoid dermatitis, may lead to more PIH. Using noncomedogenic moisturizers and applying medication appropriately (ie, a pea-sized amount of topical retinoid per application) may help limit irritation.^4,5
• One type of acne seen more commonly, although not exclusively, in Black patients is pomade acne, which principally appears on the forehead and is associated with use of hair care and styling products (FIGURE C).

Health disparity highlight

Disparities in access to health care exist for those with dermatologic concerns. According to one study, African American (28.5%) and Hispanic patients (23.9%) were less likely to be seen by a dermatologist solely for the diagnosis of a dermatologic condition compared to Asian and Pacific Islander patients (36.7%) or White patients (43.2%).¹ Noting that isotretinoin is the most potent systemic therapy for severe cystic acne vulgaris, Bell et al⁶ reported that Black patients had lower odds of receiving isotretinoin compared to White patients. Hispanic patients had lower odds of receiving a topical retinoid, tretinoin, than non-Hispanic patients.⁶

THE COMPARISON

A A 27-year-old Hispanic woman with comedonal and inflammatory acne. Erythema is prominent around the inflammatory lesions. Note the pustule on the cheek surrounded by pink color.

B A teenaged Black boy with acne papules and pustules on the face. There are comedones, hyperpigmented macules, and pustules on the cheek.

C A teenaged Black girl with pomade acne. The patient used various hair care products, which obstructed the pilosebaceous units on the forehead.

Epidemiology

Acne is a leading dermatologic condition in individuals with skin of color in the United States.¹

Key clinical features in people with darker skin tones include:

• erythematous or hyperpigmented papules or comedones
• hyperpigmented macules and postinflammatory hyperpigmentation (PIH)
• increased risk for keloidal scars.²

Worth noting

• Patients with darker skin tones may be more concerned with the dark marks (also referred to as scars or manchas in Spanish) than the acne itself. This PIH may be viewed by patients as the major problem.
• Acne medications such as azelaic acid and some retinoids (when applied appropriately) can treat both acne and PIH.³
• Irritation from topical acne medications, including retinoid dermatitis, may lead to more PIH. Using noncomedogenic moisturizers and applying medication appropriately (ie, a pea-sized amount of topical retinoid per application) may help limit irritation.^4,5
• One type of acne seen more commonly, although not exclusively, in Black patients is pomade acne, which principally appears on the forehead and is associated with use of hair care and styling products (FIGURE C).

Health disparity highlight

Disparities in access to health care exist for those with dermatologic concerns. According to one study, African American (28.5%) and Hispanic patients (23.9%) were less likely to be seen by a dermatologist solely for the diagnosis of a dermatologic condition compared to Asian and Pacific Islander patients (36.7%) or White patients (43.2%).¹ Noting that isotretinoin is the most potent systemic therapy for severe cystic acne vulgaris, Bell et al⁶ reported that Black patients had lower odds of receiving isotretinoin compared to White patients. Hispanic patients had lower odds of receiving a topical retinoid, tretinoin, than non-Hispanic patients.⁶

Photographs courtesy of Richard P. Usatine, MD.

THE COMPARISON

A A 27-year-old Hispanic woman with comedonal and inflammatory acne. Erythema is prominent around the inflammatory lesions. Note the pustule on the cheek surrounded by pink color.

B A teenaged Black boy with acne papules and pustules on the face. There are comedones, hyperpigmented macules, and pustules on the cheek.

C A teenaged Black girl with pomade acne. The patient used various hair care products, which obstructed the pilosebaceous units on the forehead.

Epidemiology

Acne is a leading dermatologic condition in individuals with skin of color in the United States.¹

Key clinical features in people with darker skin tones include:

• erythematous or hyperpigmented papules or comedones
• hyperpigmented macules and postinflammatory hyperpigmentation (PIH)
• increased risk for keloidal scars.²

Worth noting

• Patients with darker skin tones may be more concerned with the dark marks (also referred to as scars or manchas in Spanish) than the acne itself. This PIH may be viewed by patients as the major problem.
• Acne medications such as azelaic acid and some retinoids (when applied appropriately) can treat both acne and PIH.³
• Irritation from topical acne medications, including retinoid dermatitis, may lead to more PIH. Using noncomedogenic moisturizers and applying medication appropriately (ie, a pea-sized amount of topical retinoid per application) may help limit irritation.^4,5
• One type of acne seen more commonly, although not exclusively, in Black patients is pomade acne, which principally appears on the forehead and is associated with use of hair care and styling products (Figure, C).

Health disparity highlight

Disparities in access to health care exist for those with dermatologic concerns. According to one study, African American (28.5%) and Hispanic patients (23.9%) were less likely to be seen by a dermatologist solely for the diagnosis of a dermatologic condition compared to Asian and Pacific Islander patients (36.7%) or White patients (43.2%).¹

Noting that isotretinoin is the most potent systemic therapy for severe cystic acne vulgaris, Bell et al⁶ reported that Black patients had lower odds of receiving isotretinoin compared to White patients. Hispanic patients had lower odds of receiving a topical retinoid, tretinoin, than non-Hispanic patients.⁶ 

Photographs courtesy of Richard P. Usatine, MD.

THE COMPARISON

A A 27-year-old Hispanic woman with comedonal and inflammatory acne. Erythema is prominent around the inflammatory lesions. Note the pustule on the cheek surrounded by pink color.

B A teenaged Black boy with acne papules and pustules on the face. There are comedones, hyperpigmented macules, and pustules on the cheek.

C A teenaged Black girl with pomade acne. The patient used various hair care products, which obstructed the pilosebaceous units on the forehead.

Epidemiology

Acne is a leading dermatologic condition in individuals with skin of color in the United States.¹

Key clinical features in people with darker skin tones include:

• erythematous or hyperpigmented papules or comedones
• hyperpigmented macules and postinflammatory hyperpigmentation (PIH)
• increased risk for keloidal scars.²

Worth noting

• Patients with darker skin tones may be more concerned with the dark marks (also referred to as scars or manchas in Spanish) than the acne itself. This PIH may be viewed by patients as the major problem.
• Acne medications such as azelaic acid and some retinoids (when applied appropriately) can treat both acne and PIH.³
• Irritation from topical acne medications, including retinoid dermatitis, may lead to more PIH. Using noncomedogenic moisturizers and applying medication appropriately (ie, a pea-sized amount of topical retinoid per application) may help limit irritation.^4,5
• One type of acne seen more commonly, although not exclusively, in Black patients is pomade acne, which principally appears on the forehead and is associated with use of hair care and styling products (Figure, C).

Health disparity highlight

Disparities in access to health care exist for those with dermatologic concerns. According to one study, African American (28.5%) and Hispanic patients (23.9%) were less likely to be seen by a dermatologist solely for the diagnosis of a dermatologic condition compared to Asian and Pacific Islander patients (36.7%) or White patients (43.2%).¹

Noting that isotretinoin is the most potent systemic therapy for severe cystic acne vulgaris, Bell et al⁶ reported that Black patients had lower odds of receiving isotretinoin compared to White patients. Hispanic patients had lower odds of receiving a topical retinoid, tretinoin, than non-Hispanic patients.⁶ 

Photographs courtesy of Richard P. Usatine, MD.

THE COMPARISON

A A 27-year-old Hispanic woman with comedonal and inflammatory acne. Erythema is prominent around the inflammatory lesions. Note the pustule on the cheek surrounded by pink color.

B A teenaged Black boy with acne papules and pustules on the face. There are comedones, hyperpigmented macules, and pustules on the cheek.

C A teenaged Black girl with pomade acne. The patient used various hair care products, which obstructed the pilosebaceous units on the forehead.

Epidemiology

Acne is a leading dermatologic condition in individuals with skin of color in the United States.¹

Key clinical features in people with darker skin tones include:

• erythematous or hyperpigmented papules or comedones
• hyperpigmented macules and postinflammatory hyperpigmentation (PIH)
• increased risk for keloidal scars.²

Worth noting

• Patients with darker skin tones may be more concerned with the dark marks (also referred to as scars or manchas in Spanish) than the acne itself. This PIH may be viewed by patients as the major problem.
• Acne medications such as azelaic acid and some retinoids (when applied appropriately) can treat both acne and PIH.³
• Irritation from topical acne medications, including retinoid dermatitis, may lead to more PIH. Using noncomedogenic moisturizers and applying medication appropriately (ie, a pea-sized amount of topical retinoid per application) may help limit irritation.^4,5
• One type of acne seen more commonly, although not exclusively, in Black patients is pomade acne, which principally appears on the forehead and is associated with use of hair care and styling products (Figure, C).

Health disparity highlight

Disparities in access to health care exist for those with dermatologic concerns. According to one study, African American (28.5%) and Hispanic patients (23.9%) were less likely to be seen by a dermatologist solely for the diagnosis of a dermatologic condition compared to Asian and Pacific Islander patients (36.7%) or White patients (43.2%).¹

Noting that isotretinoin is the most potent systemic therapy for severe cystic acne vulgaris, Bell et al⁶ reported that Black patients had lower odds of receiving isotretinoin compared to White patients. Hispanic patients had lower odds of receiving a topical retinoid, tretinoin, than non-Hispanic patients.⁶ 

THE COMPARISON

A Elbow and forearm with erythematous, well-demarcated, pink plaques with mild micaceous scale in a 42-year-old White woman.

B Elbow and forearm with violaceous, well-demarcated plaques with micaceous scale and hyperpigmented patches around the active plaques in a 58-year-old Black man.

Epidemiology

Psoriasis prevalence in the United States has been estimated at 3.7%.^1-3 If broken down by race or ethnicity, the prevalence of psoriasis varies: 2.5% to 3.7% in White adults^1-4; 1.3% to 2% in Black adults^1-4; 1.6% in Hispanics/other adults^1-3; 1% in children overall; 0.29% in White children^1,5; and 0.06% in Black children.^1,5

Key clinical features in people with darker skin tones include:

• plaques that may appear more violaceous in color instead of pink or erythematous
• higher body surface area of involvement⁴ and thicker, more scaly plaques⁶
• increased likelihood of postinflammatory hyperpigmentation (PIH).

Worth noting

Although individuals of all skin tones may experience the psychosocial impact of psoriasis, quality-of-life measures have been found to be worse in those with skin of color (SOC) compared to White patients. ^1,4 This may be due to the lingering PIH and hypopigmentation that occurs even after inflammatory plaques are treated. Of course, lack of access to care contributes to greater disease burden and more devastating psychological impact.

Health disparity highlight

Psoriasis may be underreported and underdiagnosed in individuals with SOC, as factors contributing to health care disparities may play a role, such as access to health care in general,^1,7 and access to clinicians proficient in diagnosing cutaneous diseases in SOC may be delayed.⁸

Biologic medications are used less often in Black patients than in White patients, despite biologic medications being very efficacious for treatment of psoriasis.^1,9,10

THE COMPARISON

A Elbow and forearm with erythematous, well-demarcated, pink plaques with mild micaceous scale in a 42-year-old White woman.

B Elbow and forearm with violaceous, well-demarcated plaques with micaceous scale and hyperpigmented patches around the active plaques in a 58-year-old Black man.

Epidemiology

Psoriasis prevalence in the United States has been estimated at 3.7%.^1-3 If broken down by race or ethnicity, the prevalence of psoriasis varies: 2.5% to 3.7% in White adults^1-4; 1.3% to 2% in Black adults^1-4; 1.6% in Hispanics/other adults^1-3; 1% in children overall; 0.29% in White children^1,5; and 0.06% in Black children.^1,5

Key clinical features in people with darker skin tones include:

• plaques that may appear more violaceous in color instead of pink or erythematous
• higher body surface area of involvement⁴ and thicker, more scaly plaques⁶
• increased likelihood of postinflammatory hyperpigmentation (PIH).

Worth noting

Although individuals of all skin tones may experience the psychosocial impact of psoriasis, quality-of-life measures have been found to be worse in those with skin of color (SOC) compared to White patients. ^1,4 This may be due to the lingering PIH and hypopigmentation that occurs even after inflammatory plaques are treated. Of course, lack of access to care contributes to greater disease burden and more devastating psychological impact.

Health disparity highlight

Psoriasis may be underreported and underdiagnosed in individuals with SOC, as factors contributing to health care disparities may play a role, such as access to health care in general,^1,7 and access to clinicians proficient in diagnosing cutaneous diseases in SOC may be delayed.⁸

Biologic medications are used less often in Black patients than in White patients, despite biologic medications being very efficacious for treatment of psoriasis.^1,9,10

THE COMPARISON

A Elbow and forearm with erythematous, well-demarcated, pink plaques with mild micaceous scale in a 42-year-old White woman.

B Elbow and forearm with violaceous, well-demarcated plaques with micaceous scale and hyperpigmented patches around the active plaques in a 58-year-old Black man.

Epidemiology

Psoriasis prevalence in the United States has been estimated at 3.7%.^1-3 If broken down by race or ethnicity, the prevalence of psoriasis varies: 2.5% to 3.7% in White adults^1-4; 1.3% to 2% in Black adults^1-4; 1.6% in Hispanics/other adults^1-3; 1% in children overall; 0.29% in White children^1,5; and 0.06% in Black children.^1,5

Key clinical features in people with darker skin tones include:

• plaques that may appear more violaceous in color instead of pink or erythematous
• higher body surface area of involvement⁴ and thicker, more scaly plaques⁶
• increased likelihood of postinflammatory hyperpigmentation (PIH).

Worth noting

Although individuals of all skin tones may experience the psychosocial impact of psoriasis, quality-of-life measures have been found to be worse in those with skin of color (SOC) compared to White patients. ^1,4 This may be due to the lingering PIH and hypopigmentation that occurs even after inflammatory plaques are treated. Of course, lack of access to care contributes to greater disease burden and more devastating psychological impact.

Health disparity highlight

Psoriasis may be underreported and underdiagnosed in individuals with SOC, as factors contributing to health care disparities may play a role, such as access to health care in general,^1,7 and access to clinicians proficient in diagnosing cutaneous diseases in SOC may be delayed.⁸

Biologic medications are used less often in Black patients than in White patients, despite biologic medications being very efficacious for treatment of psoriasis.^1,9,10

The Comparison

A Elbow and forearm with erythematous, well-demarcated, pink plaques with mild micaceous scale in a 42-year-old White woman.

B Elbow and forearm with violaceous, well-demarcated plaques with micaceous scale and hyperpigmented patches around the active plaques in a 58-year-old Black man.

Epidemiology
Psoriasis prevalence in the United States has been estimated at 3.7%.^1-3 If broken down by race or ethnicity, the prevalence of psoriasis varies: 2.5% to 3.7% in White adults^1-4; 1.3% to 2% in Black adults^1-4; 1.6% in Hispanics/ other adults^1-3; 1% in children overall; 0.29% in White children_^1,5; and 0.06% in Black children.^1,5

Key clinical features in people with darker skin tones include:

• plaques that may appear more violaceous in color instead of pink or erythematous
• higher body surface area of involvement4 and thicker, more scaly plaques⁶
• increased likelihood of postinflammatory hyperpigmentation (PIH).

Worth noting
Although individuals of all skin tones may experience the psychosocial impact of psoriasis, quality-of-life measures have been found to be worse in those with skin of color (SOC) compared to White patients.^1,4 This may be due to the lingering PIH and hypopigmentation that occurs even after inflammatory plaques are treated. Of course, lack of access to care contributes to greater disease burden and more devastating psychological impact.

Health disparity highlight
Psoriasis may be underreported and underdiagnosed in individuals with SOC, as factors contributing to health care disparities may play a role, such as access to health care in general,^1,7 and access to clinicians proficient in diagnosing cutaneous diseases in SOC may be delayed.⁸

Biologic medications are used less often in Black patients than in White patients, despite biologic medications being very efficacious for treatment of psoriasis.^1,9,10

The Comparison

A Elbow and forearm with erythematous, well-demarcated, pink plaques with mild micaceous scale in a 42-year-old White woman.

B Elbow and forearm with violaceous, well-demarcated plaques with micaceous scale and hyperpigmented patches around the active plaques in a 58-year-old Black man.

Epidemiology
Psoriasis prevalence in the United States has been estimated at 3.7%.^1-3 If broken down by race or ethnicity, the prevalence of psoriasis varies: 2.5% to 3.7% in White adults^1-4; 1.3% to 2% in Black adults^1-4; 1.6% in Hispanics/ other adults^1-3; 1% in children overall; 0.29% in White children_^1,5; and 0.06% in Black children.^1,5

Key clinical features in people with darker skin tones include:

• plaques that may appear more violaceous in color instead of pink or erythematous
• higher body surface area of involvement4 and thicker, more scaly plaques⁶
• increased likelihood of postinflammatory hyperpigmentation (PIH).

Worth noting
Although individuals of all skin tones may experience the psychosocial impact of psoriasis, quality-of-life measures have been found to be worse in those with skin of color (SOC) compared to White patients.^1,4 This may be due to the lingering PIH and hypopigmentation that occurs even after inflammatory plaques are treated. Of course, lack of access to care contributes to greater disease burden and more devastating psychological impact.

Health disparity highlight
Psoriasis may be underreported and underdiagnosed in individuals with SOC, as factors contributing to health care disparities may play a role, such as access to health care in general,^1,7 and access to clinicians proficient in diagnosing cutaneous diseases in SOC may be delayed.⁸

Biologic medications are used less often in Black patients than in White patients, despite biologic medications being very efficacious for treatment of psoriasis.^1,9,10

The Comparison

A Elbow and forearm with erythematous, well-demarcated, pink plaques with mild micaceous scale in a 42-year-old White woman.

B Elbow and forearm with violaceous, well-demarcated plaques with micaceous scale and hyperpigmented patches around the active plaques in a 58-year-old Black man.

Epidemiology
Psoriasis prevalence in the United States has been estimated at 3.7%.^1-3 If broken down by race or ethnicity, the prevalence of psoriasis varies: 2.5% to 3.7% in White adults^1-4; 1.3% to 2% in Black adults^1-4; 1.6% in Hispanics/ other adults^1-3; 1% in children overall; 0.29% in White children_^1,5; and 0.06% in Black children.^1,5

Key clinical features in people with darker skin tones include:

• plaques that may appear more violaceous in color instead of pink or erythematous
• higher body surface area of involvement4 and thicker, more scaly plaques⁶
• increased likelihood of postinflammatory hyperpigmentation (PIH).

Worth noting
Although individuals of all skin tones may experience the psychosocial impact of psoriasis, quality-of-life measures have been found to be worse in those with skin of color (SOC) compared to White patients.^1,4 This may be due to the lingering PIH and hypopigmentation that occurs even after inflammatory plaques are treated. Of course, lack of access to care contributes to greater disease burden and more devastating psychological impact.

Health disparity highlight
Psoriasis may be underreported and underdiagnosed in individuals with SOC, as factors contributing to health care disparities may play a role, such as access to health care in general,^1,7 and access to clinicians proficient in diagnosing cutaneous diseases in SOC may be delayed.⁸

Biologic medications are used less often in Black patients than in White patients, despite biologic medications being very efficacious for treatment of psoriasis.^1,9,10

THE COMPARISON

A Pink scaling plaques and erythematous erosions in the antecubital fossae of a 6-year-old White boy.

B Violaceous, hyperpigmented, nummular plaques on the back and extensor surface of the right arm of a 16-month-old Black girl.

C Atopic dermatitis and follicular prominence/accentuation on the neck of a young Black girl.

Epidemiology

People of African descent have the highest atopic dermatitis prevalence and severity.

Key clinical features in people with darker skin tones include:

• follicular prominence
• papular morphology
• prurigo nodules
• hyperpigmented, violaceous-brown or gray plaques instead of erythematous plaques
• lichenification
• treatment resistant.^1,2

Worth noting

Postinflammatory hyperpigmentation and postinflammatory hypopigmentation may be more distressing to the patient/family than the atopic dermatitis itself.

Health disparity highlight

In the United States, patients with skin of color are more likely to be hospitalized with severe atopic dermatitis, have more substantial out-of-pocket costs, be underinsured, and have an increased number of missed days of work. Limited access to outpatient health care plays a role in exacerbating this health disparity.^3,4

THE COMPARISON

A Pink scaling plaques and erythematous erosions in the antecubital fossae of a 6-year-old White boy.

B Violaceous, hyperpigmented, nummular plaques on the back and extensor surface of the right arm of a 16-month-old Black girl.

C Atopic dermatitis and follicular prominence/accentuation on the neck of a young Black girl.

Epidemiology

People of African descent have the highest atopic dermatitis prevalence and severity.

Key clinical features in people with darker skin tones include:

• follicular prominence
• papular morphology
• prurigo nodules
• hyperpigmented, violaceous-brown or gray plaques instead of erythematous plaques
• lichenification
• treatment resistant.^1,2

Worth noting

Postinflammatory hyperpigmentation and postinflammatory hypopigmentation may be more distressing to the patient/family than the atopic dermatitis itself.

Health disparity highlight

In the United States, patients with skin of color are more likely to be hospitalized with severe atopic dermatitis, have more substantial out-of-pocket costs, be underinsured, and have an increased number of missed days of work. Limited access to outpatient health care plays a role in exacerbating this health disparity.^3,4

THE COMPARISON

A Pink scaling plaques and erythematous erosions in the antecubital fossae of a 6-year-old White boy.

B Violaceous, hyperpigmented, nummular plaques on the back and extensor surface of the right arm of a 16-month-old Black girl.

C Atopic dermatitis and follicular prominence/accentuation on the neck of a young Black girl.

Epidemiology

People of African descent have the highest atopic dermatitis prevalence and severity.

Key clinical features in people with darker skin tones include:

• follicular prominence
• papular morphology
• prurigo nodules
• hyperpigmented, violaceous-brown or gray plaques instead of erythematous plaques
• lichenification
• treatment resistant.^1,2

Worth noting

Postinflammatory hyperpigmentation and postinflammatory hypopigmentation may be more distressing to the patient/family than the atopic dermatitis itself.

Health disparity highlight

In the United States, patients with skin of color are more likely to be hospitalized with severe atopic dermatitis, have more substantial out-of-pocket costs, be underinsured, and have an increased number of missed days of work. Limited access to outpatient health care plays a role in exacerbating this health disparity.^3,4

The Comparison

A Pink scaling plaques and erythematous erosions in the antecubital fossae of a 6-year-old White boy.

B Violaceous, hyperpigmented, nummular plaques on the back and extensor surface of the right arm of a 16-month-old Black girl.

C Atopic dermatitis and follicular prominence/accentuation on the neck of a young Black girl.

Epidemiology

People of African descent have the highest atopic dermatitis prevalence and severity.

Key clinical features in people with darker skin tones include:

• follicular prominence
• papular morphology
• prurigo nodules
• hyperpigmented, violaceous-brown or gray plaques instead of erythematous plaques
• lichenification
• treatment resistant.^1,2

Worth noting
Postinflammatory hyperpigmentation and postinflammatory hypopigmentation may be more distressing to the patient/family than the atopic dermatitis itself.

Health disparity highlight
In the United States, patients with skin of color are more likely to be hospitalized with severe atopic dermatitis, have more substantial out-ofpocket costs, be underinsured, and have an increased number of missed days of work. Limited access to outpatient health care plays a role in exacerbating this health disparity.^3,4

The Comparison

A Pink scaling plaques and erythematous erosions in the antecubital fossae of a 6-year-old White boy.

B Violaceous, hyperpigmented, nummular plaques on the back and extensor surface of the right arm of a 16-month-old Black girl.

C Atopic dermatitis and follicular prominence/accentuation on the neck of a young Black girl.

Epidemiology

People of African descent have the highest atopic dermatitis prevalence and severity.

Key clinical features in people with darker skin tones include:

• follicular prominence
• papular morphology
• prurigo nodules
• hyperpigmented, violaceous-brown or gray plaques instead of erythematous plaques
• lichenification
• treatment resistant.^1,2

Worth noting
Postinflammatory hyperpigmentation and postinflammatory hypopigmentation may be more distressing to the patient/family than the atopic dermatitis itself.

Health disparity highlight
In the United States, patients with skin of color are more likely to be hospitalized with severe atopic dermatitis, have more substantial out-ofpocket costs, be underinsured, and have an increased number of missed days of work. Limited access to outpatient health care plays a role in exacerbating this health disparity.^3,4

The Comparison

A Pink scaling plaques and erythematous erosions in the antecubital fossae of a 6-year-old White boy.

B Violaceous, hyperpigmented, nummular plaques on the back and extensor surface of the right arm of a 16-month-old Black girl.

C Atopic dermatitis and follicular prominence/accentuation on the neck of a young Black girl.

Epidemiology

People of African descent have the highest atopic dermatitis prevalence and severity.

Key clinical features in people with darker skin tones include:

• follicular prominence
• papular morphology
• prurigo nodules
• hyperpigmented, violaceous-brown or gray plaques instead of erythematous plaques
• lichenification
• treatment resistant.^1,2

Worth noting
Postinflammatory hyperpigmentation and postinflammatory hypopigmentation may be more distressing to the patient/family than the atopic dermatitis itself.

Health disparity highlight
In the United States, patients with skin of color are more likely to be hospitalized with severe atopic dermatitis, have more substantial out-ofpocket costs, be underinsured, and have an increased number of missed days of work. Limited access to outpatient health care plays a role in exacerbating this health disparity.^3,4

A 62-year-old man presented to our skin clinic with multiple pruritic, tense, bullous lesions that manifested on his arms, abdomen, back, and upper thighs over a 1-month period. There were no lesions in his oral cavity or around his eyes, nose, or penile region. He denied dysphagia.

The patient had multiple comorbidities, including diabetes, hypertension, recent stroke, and end-stage renal disease. He was being prepared for dialysis. His medications included torsemide, warfarin, amiodarone, metoprolol, pantoprozole, atorvastatin, and nifedipine. About 3 months prior to this presentation, he was started on oral linaglipton 5 mg/d, an oral antihyperglycemic medication. He had no history of skin disease or cancer, and his family history was not significant.

Physical examination showed multiple 5-mm to 2-cm blisters and bullae on the flexural surface of both of his arms (FIGURE), back, lower abdomen, and upper thighs. His palms and soles were not involved. The lesions were nontender, tense, and filled with clear fluid. Some were intact and others were rupturing. There was no mucocutaneous involvement. Nikolsky sign was negative. There were no signs of bleeding.

The family physician (FP) obtained a 4-mm punch biopsy at the edge of a 6-mm blister for light microscopy and a 3-mm perilesional punch biopsy for direct immunofluorescence (DIF) microscopy.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

DIF of the biopsy sample demonstrated linear deposition of complement 3 (C3) and immunoglobulin (Ig) G along the basement membrane zone. Indirect immunofluorescence on salt-split skin demonstrated linear deposition of IgG and C3 on both the roof and floor of the induced blisters. These findings and the patient’s clinical presentation met the criteria for bullous pemphigoid (BP), which is the most common autoimmune skin-blistering disease.¹

FPs are increasingly using DPP-4 inhibitors as oral antihyperglycemic agents for type 2 diabetes mellitus. Therefore, it’s important to recognize this medication class’s association with BP

BP is associated with subepidermal blistering, which can occur in reaction to a variety of triggers. Pathogenesis of this condition involves IgG anti-basement membrane autoantibody complex formation with the hemidesmosomal antigens BP230 and BP180—a process that activates C3 and the release of proteases that can be destructive to tissue along the dermo-epidermal junction.¹

Growing incidence. BP usually occurs in patients > 60 years, with no racial or gender preference.¹ The incidence rate of BP ranges from 2.4 to 21.7 new cases per 1 million individuals among various worldwide populations.² The incidence appears to have increased 1.9- to 4.3-fold over the past 2 decades.²

What you’ll see, who’s at risk

Symptoms of BP include localized areas of erythema or pruritic urticarial plaques that gradually become more extensive. A patient may have pruritis alone for an extended period prior to developing blisters and bullae. The bullae are tense and normally 1 to 7 cm in size.¹ Eruption is generalized, mostly affecting the lower abdomen, as well as the flexural parts of the extremities. The palms and soles also can be affected.

FPs should be aware of the atypical clinical variants of BP. In a review by Kridin and Ludwig, variants can be prurigo-like, eczema-like, urticaria-like, dyshidrosiform type, erosive type, and erythema annulare centrifugum–like type.² At-risk populations, such as elderly patients (> 70 years), whose pruritis manifests with or without bullous formation, should be screened for BP.^3,4

Continue to: Risk factors for BP

Risk factors for BP. Certain conditions linked to developing BP include neurologic disorders (dementia and Parkinson disease) and psychiatric disorders (unipolar and bipolar disorder).⁴ Further, it is important to note any medications that could be the cause of a patient’s BP, including dipeptidyl peptidase-4 (DPP-4) inhibitors, psychotropic medications, spironolactone, furosemide, beta-blockers, and antibiotics.³ This patient was taking a beta-blocker (metoprolol) and a DPP-4 inhibitor (linagliptin). Because he was most recently started on linagliptin, we suspected it may have had a causal role in the development of BP.

The association of DPP-4 inhibitors and BP

FPs are increasingly using DPP-4 inhibitors—including sitagliptin, vildagliptin, and linagliptin—as oral antihyperglycemic agents for type 2 diabetes mellitus. Therefore, it’s important to recognize this medication class’s association with BP.⁵ In a case-control study of 165 patients with BP, Benzaquen et al reported that 28 patients who were taking DPP-4 inhibitors had an associated increased risk for BP (adjusted odds ratio = 2.64; 95% confidence interval [CI], 1.19-5.85).³

The pathophysiology of BP associated with DPP-4 inhibitors remains unclear, but mechanisms have been proposed. The DPP-4 enzyme is expressed on many cells, including keratinocytes, T cells, and endothelial cells.³ It is possible that DPP-4 inhibition at these cells could stimulate activity of inflammatory cytokines, which can lead to enhanced local eosinophil activation and trigger bullous formation. DPP-4 enzymes are also involved in forming plasmin, which is a protease that cleaves BP180.³ Inhibition of this process can affect proper cleavage of BP180, impacting its function and antigenicity.^3,6

Other conditions that also exhibit blisters

There are some skin conditions with similar presentations that need to be ruled out in the work-up.

Bullous diabeticorum is a rare, spontaneous, noninflammatory condition found in patients with diabetes.¹ Blisters usually manifest as large, tense, asymmetrical, mildly tender lesions that commonly affect the feet and lower legs but can involve the trunk. These usually develop overnight without preceding trauma. Biopsy would show both intra-­epidermal and subepidermal bulla with normal DIF findings.¹ This condition usually has an excellent prognosis.

Continue to: Pemphigus vulgaris

Pemphigus vulgaris is characterized by nonpruritic, flaccid, painful blisters. This condition usually begins with manifestation of painful oral lesions that evolve into skin blisters. Some patients can develop mucocutaneous lesions.¹ Nikolsky sign is positive in these cases. Light microscopy would show intra-­epidermal bullae.

Dermatitis herpetiformis. This condition—usually affecting middle-age patients—is associated with severe pruritis and burning. It may start with a few pruritic papules or vesicles that later evolve into urticarial papules, vesicles, or bullae. Dermatitis herpetiformis can resemble herpes simplex virus. It can also be associated with gluten-sensitive enteropathy and small bowel lymphoma.¹ DIF of a biopsy sample would show granular deposition of IgA within the tips of the dermal papillae and along the basement membrane of perilesional skin.¹

Epidermolysis bullosa acquisita is a rare, severe, chronic condition with subepidermal mucocutaneous blistering.¹ It is associated with skin fragility and spontaneous trauma-induced blisters that heal with scar formation and milia. IgG autoantibodies reacting to proteins in the basement membrane zone can cause the disease. It is also associated with Crohn disease.¹ DIF findings are similar in BP, but they are differentiated by location of IgG deposits; they can be found on the dermal side of separation in epidermolysis bullosa acquisita, as compared with the epidermal side in BP.¹

How to make the Dx in 3 steps

To effectively diagnose and classify BP, use the following 3-step method:

1. Establish the presence of 3 of 4 ­clinical characteristics: patient’s age > 60 years, absence of atrophic scars, absence of mucosal involvement, and absence of bullous lesions on the head and neck.
2. Order light microscopy. Findings should be consistent with eosinophils and neutrophils containing subepidermal bullae.
3. Order a punch biopsy to obtain a perilesional specimen. DIF of the biopsy findings should feature linear deposits of IgG with or without C3 along the dermo-epidermal junction. This step is essential for an accurate diagnosis.

Depending on the severity of disease, treatment can include the use of potent topical corticosteroids alone or in combination with systemic corticosteroids and antiinflammatory antibiotics.

There also is benefit in ordering supplemental studies, such as an enzyme-linked immunosorbent assay for the detection of anti-BP180 or anti-BP230 IgG autoantibodies.⁷ However, for this patient, we did not order this study.

Continue to: Management focuses on steroids

Management focuses on steroids

The offending agent should be discontinued immediately. Depending on the severity of disease, treatment can include the use of potent topical corticosteroids alone or in combination with systemic corticosteroids and anti-inflammatory antibiotics (eg, doxycycline, minocycline, erythromycin).^1,7 For patients with resistant or refractory disease, consider azathioprine, methotrexate, dapsone, and chlorambucil.^1,7 Exceptional cases may benefit from the use of mycophenolate mofetil, intravenous immunoglobulin, or plasmapheresis.^1,7

For this patient, initial treatment included discontinuation of linagliption and introduction of topical clobetasol 0.05% and oral prednisone 40 mg/d for 7 days, followed by prednisone 20 mg for 7 days. He was also started on oral doxycycline 100 mg bid and oral nicotinamide 500 mg bid.

A 62-year-old man presented to our skin clinic with multiple pruritic, tense, bullous lesions that manifested on his arms, abdomen, back, and upper thighs over a 1-month period. There were no lesions in his oral cavity or around his eyes, nose, or penile region. He denied dysphagia.

The patient had multiple comorbidities, including diabetes, hypertension, recent stroke, and end-stage renal disease. He was being prepared for dialysis. His medications included torsemide, warfarin, amiodarone, metoprolol, pantoprozole, atorvastatin, and nifedipine. About 3 months prior to this presentation, he was started on oral linaglipton 5 mg/d, an oral antihyperglycemic medication. He had no history of skin disease or cancer, and his family history was not significant.

Physical examination showed multiple 5-mm to 2-cm blisters and bullae on the flexural surface of both of his arms (FIGURE), back, lower abdomen, and upper thighs. His palms and soles were not involved. The lesions were nontender, tense, and filled with clear fluid. Some were intact and others were rupturing. There was no mucocutaneous involvement. Nikolsky sign was negative. There were no signs of bleeding.

The family physician (FP) obtained a 4-mm punch biopsy at the edge of a 6-mm blister for light microscopy and a 3-mm perilesional punch biopsy for direct immunofluorescence (DIF) microscopy.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

DIF of the biopsy sample demonstrated linear deposition of complement 3 (C3) and immunoglobulin (Ig) G along the basement membrane zone. Indirect immunofluorescence on salt-split skin demonstrated linear deposition of IgG and C3 on both the roof and floor of the induced blisters. These findings and the patient’s clinical presentation met the criteria for bullous pemphigoid (BP), which is the most common autoimmune skin-blistering disease.¹

FPs are increasingly using DPP-4 inhibitors as oral antihyperglycemic agents for type 2 diabetes mellitus. Therefore, it’s important to recognize this medication class’s association with BP

BP is associated with subepidermal blistering, which can occur in reaction to a variety of triggers. Pathogenesis of this condition involves IgG anti-basement membrane autoantibody complex formation with the hemidesmosomal antigens BP230 and BP180—a process that activates C3 and the release of proteases that can be destructive to tissue along the dermo-epidermal junction.¹

Growing incidence. BP usually occurs in patients > 60 years, with no racial or gender preference.¹ The incidence rate of BP ranges from 2.4 to 21.7 new cases per 1 million individuals among various worldwide populations.² The incidence appears to have increased 1.9- to 4.3-fold over the past 2 decades.²

What you’ll see, who’s at risk

Symptoms of BP include localized areas of erythema or pruritic urticarial plaques that gradually become more extensive. A patient may have pruritis alone for an extended period prior to developing blisters and bullae. The bullae are tense and normally 1 to 7 cm in size.¹ Eruption is generalized, mostly affecting the lower abdomen, as well as the flexural parts of the extremities. The palms and soles also can be affected.

FPs should be aware of the atypical clinical variants of BP. In a review by Kridin and Ludwig, variants can be prurigo-like, eczema-like, urticaria-like, dyshidrosiform type, erosive type, and erythema annulare centrifugum–like type.² At-risk populations, such as elderly patients (> 70 years), whose pruritis manifests with or without bullous formation, should be screened for BP.^3,4

Continue to: Risk factors for BP

Risk factors for BP. Certain conditions linked to developing BP include neurologic disorders (dementia and Parkinson disease) and psychiatric disorders (unipolar and bipolar disorder).⁴ Further, it is important to note any medications that could be the cause of a patient’s BP, including dipeptidyl peptidase-4 (DPP-4) inhibitors, psychotropic medications, spironolactone, furosemide, beta-blockers, and antibiotics.³ This patient was taking a beta-blocker (metoprolol) and a DPP-4 inhibitor (linagliptin). Because he was most recently started on linagliptin, we suspected it may have had a causal role in the development of BP.

The association of DPP-4 inhibitors and BP

FPs are increasingly using DPP-4 inhibitors—including sitagliptin, vildagliptin, and linagliptin—as oral antihyperglycemic agents for type 2 diabetes mellitus. Therefore, it’s important to recognize this medication class’s association with BP.⁵ In a case-control study of 165 patients with BP, Benzaquen et al reported that 28 patients who were taking DPP-4 inhibitors had an associated increased risk for BP (adjusted odds ratio = 2.64; 95% confidence interval [CI], 1.19-5.85).³

The pathophysiology of BP associated with DPP-4 inhibitors remains unclear, but mechanisms have been proposed. The DPP-4 enzyme is expressed on many cells, including keratinocytes, T cells, and endothelial cells.³ It is possible that DPP-4 inhibition at these cells could stimulate activity of inflammatory cytokines, which can lead to enhanced local eosinophil activation and trigger bullous formation. DPP-4 enzymes are also involved in forming plasmin, which is a protease that cleaves BP180.³ Inhibition of this process can affect proper cleavage of BP180, impacting its function and antigenicity.^3,6

Other conditions that also exhibit blisters

There are some skin conditions with similar presentations that need to be ruled out in the work-up.

Bullous diabeticorum is a rare, spontaneous, noninflammatory condition found in patients with diabetes.¹ Blisters usually manifest as large, tense, asymmetrical, mildly tender lesions that commonly affect the feet and lower legs but can involve the trunk. These usually develop overnight without preceding trauma. Biopsy would show both intra-­epidermal and subepidermal bulla with normal DIF findings.¹ This condition usually has an excellent prognosis.

Continue to: Pemphigus vulgaris

Pemphigus vulgaris is characterized by nonpruritic, flaccid, painful blisters. This condition usually begins with manifestation of painful oral lesions that evolve into skin blisters. Some patients can develop mucocutaneous lesions.¹ Nikolsky sign is positive in these cases. Light microscopy would show intra-­epidermal bullae.

Dermatitis herpetiformis. This condition—usually affecting middle-age patients—is associated with severe pruritis and burning. It may start with a few pruritic papules or vesicles that later evolve into urticarial papules, vesicles, or bullae. Dermatitis herpetiformis can resemble herpes simplex virus. It can also be associated with gluten-sensitive enteropathy and small bowel lymphoma.¹ DIF of a biopsy sample would show granular deposition of IgA within the tips of the dermal papillae and along the basement membrane of perilesional skin.¹

Epidermolysis bullosa acquisita is a rare, severe, chronic condition with subepidermal mucocutaneous blistering.¹ It is associated with skin fragility and spontaneous trauma-induced blisters that heal with scar formation and milia. IgG autoantibodies reacting to proteins in the basement membrane zone can cause the disease. It is also associated with Crohn disease.¹ DIF findings are similar in BP, but they are differentiated by location of IgG deposits; they can be found on the dermal side of separation in epidermolysis bullosa acquisita, as compared with the epidermal side in BP.¹

How to make the Dx in 3 steps

To effectively diagnose and classify BP, use the following 3-step method:

1. Establish the presence of 3 of 4 ­clinical characteristics: patient’s age > 60 years, absence of atrophic scars, absence of mucosal involvement, and absence of bullous lesions on the head and neck.
2. Order light microscopy. Findings should be consistent with eosinophils and neutrophils containing subepidermal bullae.
3. Order a punch biopsy to obtain a perilesional specimen. DIF of the biopsy findings should feature linear deposits of IgG with or without C3 along the dermo-epidermal junction. This step is essential for an accurate diagnosis.

Depending on the severity of disease, treatment can include the use of potent topical corticosteroids alone or in combination with systemic corticosteroids and antiinflammatory antibiotics.

There also is benefit in ordering supplemental studies, such as an enzyme-linked immunosorbent assay for the detection of anti-BP180 or anti-BP230 IgG autoantibodies.⁷ However, for this patient, we did not order this study.

Continue to: Management focuses on steroids

Management focuses on steroids

The offending agent should be discontinued immediately. Depending on the severity of disease, treatment can include the use of potent topical corticosteroids alone or in combination with systemic corticosteroids and anti-inflammatory antibiotics (eg, doxycycline, minocycline, erythromycin).^1,7 For patients with resistant or refractory disease, consider azathioprine, methotrexate, dapsone, and chlorambucil.^1,7 Exceptional cases may benefit from the use of mycophenolate mofetil, intravenous immunoglobulin, or plasmapheresis.^1,7

For this patient, initial treatment included discontinuation of linagliption and introduction of topical clobetasol 0.05% and oral prednisone 40 mg/d for 7 days, followed by prednisone 20 mg for 7 days. He was also started on oral doxycycline 100 mg bid and oral nicotinamide 500 mg bid.

A 62-year-old man presented to our skin clinic with multiple pruritic, tense, bullous lesions that manifested on his arms, abdomen, back, and upper thighs over a 1-month period. There were no lesions in his oral cavity or around his eyes, nose, or penile region. He denied dysphagia.

The patient had multiple comorbidities, including diabetes, hypertension, recent stroke, and end-stage renal disease. He was being prepared for dialysis. His medications included torsemide, warfarin, amiodarone, metoprolol, pantoprozole, atorvastatin, and nifedipine. About 3 months prior to this presentation, he was started on oral linaglipton 5 mg/d, an oral antihyperglycemic medication. He had no history of skin disease or cancer, and his family history was not significant.

Physical examination showed multiple 5-mm to 2-cm blisters and bullae on the flexural surface of both of his arms (FIGURE), back, lower abdomen, and upper thighs. His palms and soles were not involved. The lesions were nontender, tense, and filled with clear fluid. Some were intact and others were rupturing. There was no mucocutaneous involvement. Nikolsky sign was negative. There were no signs of bleeding.

The family physician (FP) obtained a 4-mm punch biopsy at the edge of a 6-mm blister for light microscopy and a 3-mm perilesional punch biopsy for direct immunofluorescence (DIF) microscopy.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

DIF of the biopsy sample demonstrated linear deposition of complement 3 (C3) and immunoglobulin (Ig) G along the basement membrane zone. Indirect immunofluorescence on salt-split skin demonstrated linear deposition of IgG and C3 on both the roof and floor of the induced blisters. These findings and the patient’s clinical presentation met the criteria for bullous pemphigoid (BP), which is the most common autoimmune skin-blistering disease.¹

FPs are increasingly using DPP-4 inhibitors as oral antihyperglycemic agents for type 2 diabetes mellitus. Therefore, it’s important to recognize this medication class’s association with BP

BP is associated with subepidermal blistering, which can occur in reaction to a variety of triggers. Pathogenesis of this condition involves IgG anti-basement membrane autoantibody complex formation with the hemidesmosomal antigens BP230 and BP180—a process that activates C3 and the release of proteases that can be destructive to tissue along the dermo-epidermal junction.¹

Growing incidence. BP usually occurs in patients > 60 years, with no racial or gender preference.¹ The incidence rate of BP ranges from 2.4 to 21.7 new cases per 1 million individuals among various worldwide populations.² The incidence appears to have increased 1.9- to 4.3-fold over the past 2 decades.²

What you’ll see, who’s at risk

Symptoms of BP include localized areas of erythema or pruritic urticarial plaques that gradually become more extensive. A patient may have pruritis alone for an extended period prior to developing blisters and bullae. The bullae are tense and normally 1 to 7 cm in size.¹ Eruption is generalized, mostly affecting the lower abdomen, as well as the flexural parts of the extremities. The palms and soles also can be affected.

FPs should be aware of the atypical clinical variants of BP. In a review by Kridin and Ludwig, variants can be prurigo-like, eczema-like, urticaria-like, dyshidrosiform type, erosive type, and erythema annulare centrifugum–like type.² At-risk populations, such as elderly patients (> 70 years), whose pruritis manifests with or without bullous formation, should be screened for BP.^3,4

Continue to: Risk factors for BP

Risk factors for BP. Certain conditions linked to developing BP include neurologic disorders (dementia and Parkinson disease) and psychiatric disorders (unipolar and bipolar disorder).⁴ Further, it is important to note any medications that could be the cause of a patient’s BP, including dipeptidyl peptidase-4 (DPP-4) inhibitors, psychotropic medications, spironolactone, furosemide, beta-blockers, and antibiotics.³ This patient was taking a beta-blocker (metoprolol) and a DPP-4 inhibitor (linagliptin). Because he was most recently started on linagliptin, we suspected it may have had a causal role in the development of BP.

The association of DPP-4 inhibitors and BP

FPs are increasingly using DPP-4 inhibitors—including sitagliptin, vildagliptin, and linagliptin—as oral antihyperglycemic agents for type 2 diabetes mellitus. Therefore, it’s important to recognize this medication class’s association with BP.⁵ In a case-control study of 165 patients with BP, Benzaquen et al reported that 28 patients who were taking DPP-4 inhibitors had an associated increased risk for BP (adjusted odds ratio = 2.64; 95% confidence interval [CI], 1.19-5.85).³

The pathophysiology of BP associated with DPP-4 inhibitors remains unclear, but mechanisms have been proposed. The DPP-4 enzyme is expressed on many cells, including keratinocytes, T cells, and endothelial cells.³ It is possible that DPP-4 inhibition at these cells could stimulate activity of inflammatory cytokines, which can lead to enhanced local eosinophil activation and trigger bullous formation. DPP-4 enzymes are also involved in forming plasmin, which is a protease that cleaves BP180.³ Inhibition of this process can affect proper cleavage of BP180, impacting its function and antigenicity.^3,6

Other conditions that also exhibit blisters

There are some skin conditions with similar presentations that need to be ruled out in the work-up.

Bullous diabeticorum is a rare, spontaneous, noninflammatory condition found in patients with diabetes.¹ Blisters usually manifest as large, tense, asymmetrical, mildly tender lesions that commonly affect the feet and lower legs but can involve the trunk. These usually develop overnight without preceding trauma. Biopsy would show both intra-­epidermal and subepidermal bulla with normal DIF findings.¹ This condition usually has an excellent prognosis.

Continue to: Pemphigus vulgaris

Pemphigus vulgaris is characterized by nonpruritic, flaccid, painful blisters. This condition usually begins with manifestation of painful oral lesions that evolve into skin blisters. Some patients can develop mucocutaneous lesions.¹ Nikolsky sign is positive in these cases. Light microscopy would show intra-­epidermal bullae.

Dermatitis herpetiformis. This condition—usually affecting middle-age patients—is associated with severe pruritis and burning. It may start with a few pruritic papules or vesicles that later evolve into urticarial papules, vesicles, or bullae. Dermatitis herpetiformis can resemble herpes simplex virus. It can also be associated with gluten-sensitive enteropathy and small bowel lymphoma.¹ DIF of a biopsy sample would show granular deposition of IgA within the tips of the dermal papillae and along the basement membrane of perilesional skin.¹

Epidermolysis bullosa acquisita is a rare, severe, chronic condition with subepidermal mucocutaneous blistering.¹ It is associated with skin fragility and spontaneous trauma-induced blisters that heal with scar formation and milia. IgG autoantibodies reacting to proteins in the basement membrane zone can cause the disease. It is also associated with Crohn disease.¹ DIF findings are similar in BP, but they are differentiated by location of IgG deposits; they can be found on the dermal side of separation in epidermolysis bullosa acquisita, as compared with the epidermal side in BP.¹

How to make the Dx in 3 steps

To effectively diagnose and classify BP, use the following 3-step method:

1. Establish the presence of 3 of 4 ­clinical characteristics: patient’s age > 60 years, absence of atrophic scars, absence of mucosal involvement, and absence of bullous lesions on the head and neck.
2. Order light microscopy. Findings should be consistent with eosinophils and neutrophils containing subepidermal bullae.
3. Order a punch biopsy to obtain a perilesional specimen. DIF of the biopsy findings should feature linear deposits of IgG with or without C3 along the dermo-epidermal junction. This step is essential for an accurate diagnosis.

Depending on the severity of disease, treatment can include the use of potent topical corticosteroids alone or in combination with systemic corticosteroids and antiinflammatory antibiotics.

There also is benefit in ordering supplemental studies, such as an enzyme-linked immunosorbent assay for the detection of anti-BP180 or anti-BP230 IgG autoantibodies.⁷ However, for this patient, we did not order this study.

Continue to: Management focuses on steroids

Management focuses on steroids

The offending agent should be discontinued immediately. Depending on the severity of disease, treatment can include the use of potent topical corticosteroids alone or in combination with systemic corticosteroids and anti-inflammatory antibiotics (eg, doxycycline, minocycline, erythromycin).^1,7 For patients with resistant or refractory disease, consider azathioprine, methotrexate, dapsone, and chlorambucil.^1,7 Exceptional cases may benefit from the use of mycophenolate mofetil, intravenous immunoglobulin, or plasmapheresis.^1,7

For this patient, initial treatment included discontinuation of linagliption and introduction of topical clobetasol 0.05% and oral prednisone 40 mg/d for 7 days, followed by prednisone 20 mg for 7 days. He was also started on oral doxycycline 100 mg bid and oral nicotinamide 500 mg bid.

An 11-year-old boy sought care at a small village’s health center in Panama for scalp itching and subtle hair loss. He was seen by a family physician (RU) and a team of medical students who were there as part of a humanitarian trip. The patient denied any hair pulling. He had a history of treatment for head lice.

Our physical examination revealed mild alopecia and scaling on the scalp (FIGURE 1), but what we saw through the dermatoscope (FIGURE 2) made the diagnosis clear.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

Diagnosis: Tinea capitis

On dermatoscopic examination (10× magnification), there were numerous “black dots” or broken hair shafts within patches of hair loss (FIGURE 3), which is indicative of tinea capitis.^1,2 This condition causes hair shafts to break, creating “comma hairs” and black dots. The hairs are uniform in thickness and color and bend distally, like a comma.³

Tinea capitis (commonly called ringworm of the scalp) is a fungal infection caused by Trichophyton and Microsporum dermatophytes. It is the most common pediatric dermatophyte infection in the world; the usual age of onset is 5 to 10 years.² The incidence of tinea capitis in the United States is not known because cases are no longer registered by public health agencies. That said, a Northern California study that tracked occurrences in children younger than 15 years from 1998 to 2007 found that the incidence was on the decline and lower in girls compared to boys (111.9 vs 146.4, respectively, in 1998; 27.9 vs 39.9, respectively, in 2007).⁴ Incidence rates were calculated per 10,000 eligible children.⁴

Tinea capitis can spread by contact with infected individuals and contaminated objects, including combs, towels, toys, and bedding.¹ Fungal spores can remain viable on these surfaces for months.

In a study of 69 patients with tinea capitis (23 females, 46 males; mean age, 12 years), the risk factors for spreading infection included participation in sports, contact with an animal, a recent haircut, and use of a swimming pool.⁵

4 conditions you’ll want to rule out

The following conditions should be considered as part of the differential when a patient presents with an itchy scalp and/or hair loss.

Continue to: Psoriasis of the scalp...

Psoriasis of the scalp is characterized by scaling of the scalp along with crusted plaques. It is often accompanied by similar psoriatic plaques on the elbows, knees, and other areas of the body. Examination of our patient showed no psoriatic plaques.

Seborrhea of the scalp (also known as dandruff) is a very common diagnosis. However, it is unlikely to cause hair loss. It has widespread involvement of the scalp compared to tinea capitis, which is local and patchy. Our patient’s patches of hair loss indicated that seborrhea was unlikely.

Alopecia areata. Individuals develop this condition due to an autoimmune process affecting hair follicles. However, the resulting hair loss does not cause significant scaling, inflammation, scarring, or pain in the affected area. Further, this condition can cause the loss of the entire hair shaft.

Trichotillomania is an impulse control disorder that causes patients to pull out their own hair. There is no scaling of the scalp in this condition.

A dermatoscope can beuseful in making the Dx

Although clinical appearance and patient presentation are adequate to establish the diagnosis of tinea capitis, this case demonstrates the utility of a dermatoscope in making the diagnosis of tinea capitis. Previous studies have shown that dermoscopy allows for rapid identification of the broken hair shafts, which are a key distinction from alopecia areata.^3,6

Microscopic inspection. Samples from the scaling of the scalp can be examined with potassium hydroxide (KOH) on a microscope slide. Hyphae, spores, and endo/ectothrix invasion can be seen through the microsope.  

Continue to: Laboratory testing is helpful, but not needed.

Newer antifungalsprovide a Tx advantage

Oral antifungal medications are the treatment of choice for tinea capitis. Newer antifungals, such as terbinafine and fluconazole, require a 3- to 6-week course compared to the standard 6- to 8-week course of griseofulvin.¹ Also, antifungal shampoos—such as those that contain selenium sulfide—may be used for topical treatment but only as adjuvant therapy.^1,2

For our patient, we dispensed a 3-week course of oral fluconazole, 3 to 6 mg/kg, to be given daily by his parents. We also recommended the use of an antidandruff shampoo, if possible. The treatment outcome was not known because our team’s humanitarian global health trip had ended.

An 11-year-old boy sought care at a small village’s health center in Panama for scalp itching and subtle hair loss. He was seen by a family physician (RU) and a team of medical students who were there as part of a humanitarian trip. The patient denied any hair pulling. He had a history of treatment for head lice.

Our physical examination revealed mild alopecia and scaling on the scalp (FIGURE 1), but what we saw through the dermatoscope (FIGURE 2) made the diagnosis clear.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

Diagnosis: Tinea capitis

On dermatoscopic examination (10× magnification), there were numerous “black dots” or broken hair shafts within patches of hair loss (FIGURE 3), which is indicative of tinea capitis.^1,2 This condition causes hair shafts to break, creating “comma hairs” and black dots. The hairs are uniform in thickness and color and bend distally, like a comma.³

Tinea capitis (commonly called ringworm of the scalp) is a fungal infection caused by Trichophyton and Microsporum dermatophytes. It is the most common pediatric dermatophyte infection in the world; the usual age of onset is 5 to 10 years.² The incidence of tinea capitis in the United States is not known because cases are no longer registered by public health agencies. That said, a Northern California study that tracked occurrences in children younger than 15 years from 1998 to 2007 found that the incidence was on the decline and lower in girls compared to boys (111.9 vs 146.4, respectively, in 1998; 27.9 vs 39.9, respectively, in 2007).⁴ Incidence rates were calculated per 10,000 eligible children.⁴

Tinea capitis can spread by contact with infected individuals and contaminated objects, including combs, towels, toys, and bedding.¹ Fungal spores can remain viable on these surfaces for months.

In a study of 69 patients with tinea capitis (23 females, 46 males; mean age, 12 years), the risk factors for spreading infection included participation in sports, contact with an animal, a recent haircut, and use of a swimming pool.⁵

4 conditions you’ll want to rule out

The following conditions should be considered as part of the differential when a patient presents with an itchy scalp and/or hair loss.

Continue to: Psoriasis of the scalp...

Psoriasis of the scalp is characterized by scaling of the scalp along with crusted plaques. It is often accompanied by similar psoriatic plaques on the elbows, knees, and other areas of the body. Examination of our patient showed no psoriatic plaques.

Seborrhea of the scalp (also known as dandruff) is a very common diagnosis. However, it is unlikely to cause hair loss. It has widespread involvement of the scalp compared to tinea capitis, which is local and patchy. Our patient’s patches of hair loss indicated that seborrhea was unlikely.

Alopecia areata. Individuals develop this condition due to an autoimmune process affecting hair follicles. However, the resulting hair loss does not cause significant scaling, inflammation, scarring, or pain in the affected area. Further, this condition can cause the loss of the entire hair shaft.

Trichotillomania is an impulse control disorder that causes patients to pull out their own hair. There is no scaling of the scalp in this condition.

A dermatoscope can beuseful in making the Dx

Although clinical appearance and patient presentation are adequate to establish the diagnosis of tinea capitis, this case demonstrates the utility of a dermatoscope in making the diagnosis of tinea capitis. Previous studies have shown that dermoscopy allows for rapid identification of the broken hair shafts, which are a key distinction from alopecia areata.^3,6

Microscopic inspection. Samples from the scaling of the scalp can be examined with potassium hydroxide (KOH) on a microscope slide. Hyphae, spores, and endo/ectothrix invasion can be seen through the microsope.  

Continue to: Laboratory testing is helpful, but not needed.

Newer antifungalsprovide a Tx advantage

Oral antifungal medications are the treatment of choice for tinea capitis. Newer antifungals, such as terbinafine and fluconazole, require a 3- to 6-week course compared to the standard 6- to 8-week course of griseofulvin.¹ Also, antifungal shampoos—such as those that contain selenium sulfide—may be used for topical treatment but only as adjuvant therapy.^1,2

For our patient, we dispensed a 3-week course of oral fluconazole, 3 to 6 mg/kg, to be given daily by his parents. We also recommended the use of an antidandruff shampoo, if possible. The treatment outcome was not known because our team’s humanitarian global health trip had ended.

An 11-year-old boy sought care at a small village’s health center in Panama for scalp itching and subtle hair loss. He was seen by a family physician (RU) and a team of medical students who were there as part of a humanitarian trip. The patient denied any hair pulling. He had a history of treatment for head lice.

Our physical examination revealed mild alopecia and scaling on the scalp (FIGURE 1), but what we saw through the dermatoscope (FIGURE 2) made the diagnosis clear.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

Diagnosis: Tinea capitis

On dermatoscopic examination (10× magnification), there were numerous “black dots” or broken hair shafts within patches of hair loss (FIGURE 3), which is indicative of tinea capitis.^1,2 This condition causes hair shafts to break, creating “comma hairs” and black dots. The hairs are uniform in thickness and color and bend distally, like a comma.³

Tinea capitis (commonly called ringworm of the scalp) is a fungal infection caused by Trichophyton and Microsporum dermatophytes. It is the most common pediatric dermatophyte infection in the world; the usual age of onset is 5 to 10 years.² The incidence of tinea capitis in the United States is not known because cases are no longer registered by public health agencies. That said, a Northern California study that tracked occurrences in children younger than 15 years from 1998 to 2007 found that the incidence was on the decline and lower in girls compared to boys (111.9 vs 146.4, respectively, in 1998; 27.9 vs 39.9, respectively, in 2007).⁴ Incidence rates were calculated per 10,000 eligible children.⁴

Tinea capitis can spread by contact with infected individuals and contaminated objects, including combs, towels, toys, and bedding.¹ Fungal spores can remain viable on these surfaces for months.

In a study of 69 patients with tinea capitis (23 females, 46 males; mean age, 12 years), the risk factors for spreading infection included participation in sports, contact with an animal, a recent haircut, and use of a swimming pool.⁵

4 conditions you’ll want to rule out

The following conditions should be considered as part of the differential when a patient presents with an itchy scalp and/or hair loss.

Continue to: Psoriasis of the scalp...

Psoriasis of the scalp is characterized by scaling of the scalp along with crusted plaques. It is often accompanied by similar psoriatic plaques on the elbows, knees, and other areas of the body. Examination of our patient showed no psoriatic plaques.

Seborrhea of the scalp (also known as dandruff) is a very common diagnosis. However, it is unlikely to cause hair loss. It has widespread involvement of the scalp compared to tinea capitis, which is local and patchy. Our patient’s patches of hair loss indicated that seborrhea was unlikely.

Alopecia areata. Individuals develop this condition due to an autoimmune process affecting hair follicles. However, the resulting hair loss does not cause significant scaling, inflammation, scarring, or pain in the affected area. Further, this condition can cause the loss of the entire hair shaft.

Trichotillomania is an impulse control disorder that causes patients to pull out their own hair. There is no scaling of the scalp in this condition.

A dermatoscope can beuseful in making the Dx

Although clinical appearance and patient presentation are adequate to establish the diagnosis of tinea capitis, this case demonstrates the utility of a dermatoscope in making the diagnosis of tinea capitis. Previous studies have shown that dermoscopy allows for rapid identification of the broken hair shafts, which are a key distinction from alopecia areata.^3,6

Microscopic inspection. Samples from the scaling of the scalp can be examined with potassium hydroxide (KOH) on a microscope slide. Hyphae, spores, and endo/ectothrix invasion can be seen through the microsope.  

Continue to: Laboratory testing is helpful, but not needed.

Newer antifungalsprovide a Tx advantage

Oral antifungal medications are the treatment of choice for tinea capitis. Newer antifungals, such as terbinafine and fluconazole, require a 3- to 6-week course compared to the standard 6- to 8-week course of griseofulvin.¹ Also, antifungal shampoos—such as those that contain selenium sulfide—may be used for topical treatment but only as adjuvant therapy.^1,2

For our patient, we dispensed a 3-week course of oral fluconazole, 3 to 6 mg/kg, to be given daily by his parents. We also recommended the use of an antidandruff shampoo, if possible. The treatment outcome was not known because our team’s humanitarian global health trip had ended.

Dermoscopy, the use of a handheld instrument to magnify the skin 10-fold while providing a light source, is a quick, useful, cost-effective tool for detecting melanoma in family medicine.^1-4 The device, which allows the physician to visualize structures below the stratum corneum that are not routinely discernible with the naked eye, can be attached to a smartphone so that photos can be taken and reviewed with the patient. The photo can also be reviewed after a biopsy result is obtained.

Its use among non-dermatologist US physicians appears to be relatively low, but rising. One small study of physicians working in family medicine, internal medicine, and plastic surgery found that only 15% had ever used a dermatoscope and 6% were currently using one.⁵

As a family physician, you can expand your diagnostic abilities in dermatology with the acquisition of a dermatoscope (FIGURE 1) and some time invested in learning to interpret visible patterns. With that in mind, this review focuses on the diagnosis of skin cancers and benign growths using dermoscopy. We begin with a brief look at the research on dermoscopy and how it is performed. From there, we’ll detail an algorithm to guide dermoscopic analysis. And to round things out, we provide guidance that will help you to get started. (See “Choosing a dermatoscope—and making the most of it,” and “To learn more about dermoscopy …”.)

Continue to: What the research says

Dermoscopy improves sensitivity for detecting melanoma over the naked eye alone; it also allows for the detection of melanoma at earlier stages, which improves prognosis.⁶

A meta-analysis of dermoscopy use in clinical settings showed that, following training, dermoscopy increases the average sensitivity of melanoma diagnosis from 71% to more than 90% without a significant decrease in specificity.⁷ In a study of 74 primary care physicians, there was an improvement in both clinical and dermoscopic diagnosis of melanoma among those who received training in dermoscopy, compared with a control group.⁸ Another study found that primary care physicians can reduce their baseline benign-to-melanoma ratio (the number of suspicious benign lesions biopsied to find 1 melanoma) from 9.5:1 with naked eye examination to 3.5:1 with dermoscopy.⁹

The exam begins by choosing 1 of 3 modes of dermoscopy

Dermatoscopes can have a polarized or nonpolarized light source. Some dermatoscopes combine both types of light (hybrid dermatoscopes; see “Choosing a dermatoscope—and making the most of it.”)

There are 3 modes of dermoscopy:

1. nonpolarized contact dermoscopy
2. polarized contact dermoscopy
3. polarized non-contact dermoscopy.

Dermatoscopes with nonpolarized light require direct skin contact and a liquid interface (eg, alcohol, gel, mineral oil) between the scope’s glass plate and the skin for the visualization of subsurface structures. In contrast, dermatoscopes with polarized light do not require direct skin contact or a liquid interface; however, contacting the skin and using a liquid interface will provide a sharper image.

Continue to: Two major algorithms guide dermoscopic analysis

The first of 2 major algorithms that can be used to guide dermoscopic analysis is a modified pattern analysis put forth by Kittler.¹⁰ This descriptive system based on geometric elements, patterns, colors, and clues guides the observer to a specific diagnosis without categorizing lesions as being either melanocytic or nonmelanocytic. Because this is not the preferred method of the authors, we will move on to Method 2.

The second method, a 2-step algorithm, is a qualitative system that guides the observer through differentiating melanocytic from nonmelanocytic lesions in order to differentiate nevi from melanoma (FIGURE 2). At the same time, it serves as an aid to correctly diagnose non-melanocytic lesions. The 2-step algorithm forms the foundation for the dermoscopic evaluation of skin lesions in this article.

Not all expert dermoscopists employ structured analytical systems or methods to reach a diagnosis. Because of their vast experience, many rely purely on pattern recognition. But algorithms can facilitate non-experts in dermoscopy in the differentiation of nevi from melanoma or, simply, in differentiating the benign from the malignant.

Although each algorithm has its unique criteria, all of them require training and practice and familiarity with the terms used to describe morphologic structures. The International Dermoscopy Society recently published a consensus paper designating some terms as preferred over others.¹¹

Continue to: Step 1...

Step 1 of the 2-step algorithm requires the observer to determine whether the lesion is melanocytic (ie, originates from melanocytes and, therefore, could be a melanoma) or nonmelanocytic in origin.

A melanocytic lesion usually will display at least 1 of the following structures:

• pigment network (FIGURE 3A) (This can include angulated lines.)
• negative network (FIGURE 3B) (hypopigmented lines connecting pigmented structures in a serpiginous fashion)
• streaks (FIGURE 3C)
• homogeneous blue pigmentation (FIGURE 3D)
• globules (aggregated or as a peripheral rim) (FIGURE 3E)
• pseudonetwork (facial skin) (FIGURE 3F)
• parallel pigment pattern (acral lesions) (FIGURE 3G).

Exceptions. Sometimes, nonmelanocytic lesions will present with pigment network. Dermatofibromas, for example, are one exception in which the pattern trumps the network. Two other exceptions are solar lentigo and supernumerary or accessory nipple.

If the lesion does not display any structure, it is considered structureless. In these cases, proceed to the second step to rule out a melanoma.

Doesn’t meet criteria for a melanocytic lesion?

If the lesion does not reveal any of the criteria for a melanocytic lesion, then look for structures seen in nonmelanocytic lesions: dermatofibromas; seborrheic keratosis; angiomas and angiokeratomas; sebaceous hyperplasia; clear-cell acanthomas; basal cell carcinomas (BCCs); and squamous cell carcinomas (SCCs).

Continue to: Benign nonmelanocytic lesions

Dermatofibromas are benign symmetric lesions that feel firm and may dimple upon application of lateral pressure. They are fibrotic scar-like lesions that present with 1 or more of the following dermoscopic features (FIGURE 4):

• peripheral pigment network, due to increased melanin in keratinocytes
• homogeneous brown pigmented areas
• central scar-like area
• shiny white lines
• vascular structures (ie, dotted, polymorphous vessels), usually seen within the scar-like area
• ring-like globules, usually seen in the zone between the scar-like depigmentation and the peripheral network. They correspond to widened hyperpigmented rete ridges.

Seborrheic keratosis (SK) is a benign skin growth that often has a stuck-on appearance (FIGURE 5). Features often include:

• multiple (>2) milia-like cysts
• comedo-like openings
• a network-like structure that corresponds to gyri and sulci and which in some cases can create a cerebriform pattern
• fingerprint-like structures
• moth-eaten borders
• jelly sign. This consists of semicircular u-shaped structures that have a smudged appearance and are aligned in the same direction. The appearance resembles jelly as it is spread on a piece of bread.
• hairpin (looped or twisted-looped) vessels surrounded by a white halo.

Other clues include a sharp demarcation and a negative wobble sign (which we’ll describe in a moment). The presence or absence of a wobble sign is determined by using a dermatoscope that touches the skin. Mild vertical pressure is applied to the lesion while moving the scope back and forth horizontally. If the lesion slides across the skin surface, the diagnosis of an epidermal keratinocytic tumor (ie, SK) is favored. If, on the other hand, the lesion wobbles (rolls back and forth), then the diagnosis of a neoplasm with a dermal component (ie, intradermal or compound nevus) is more likely.

Angiomas and angiokeratomas. Angiomas demonstrate lacunae that are often separated by septae (FIGURE 6). Lacunae can vary in size and color. They can be red, red-white, red-blue, maroon, blue, blue-black, or even black (when thrombosis is present).

Angiokeratomas (FIGURE 7) can reveal lacunae of varying colors including black, red, purple, and maroon. In addition, a blue-whitish veil, erythema, and hemorrhagic crusts can be present.

Continue to: Sebaceous hyperplasia...

Sebaceous hyperplasia is the overgrowth of sebaceous glands. It can mimic BCC on the face. Sebaceous hyperplasia presents with multiple vessels in a crown-like arrangement that do not cross the center of the lesion. The sebaceous glands resemble popcorn (FIGURE 8).

Clear-cell acanthoma is a benign erythematous epidermal tumor usually found on the leg with a string-of-pearls pattern. This pattern is vascular so the pearls are red in color (FIGURE 9).

Malignant nonmelanocytic lesions

BCC is the most common type of skin cancer. Features often include:

• spoke-wheel-like structures or concentric structures (FIGURE 10A)
• leaf-like areas (FIGURE 10B)
• arborizing vessels (FIGURE 10b and 10C)large blue-gray ovoid nest (FIGURE 10A)
• multiple blue-gray non-aggregated globules
• ulceration or multiple small erosions
• shiny white structures and strands (FIGURE 10C).

Additional dermoscopic clues include short, fine, superficial telangiectasias and multiple in-focus dots in a buck-shot scatter distribution.

Squamous cell carcinomas (SCCs) of the skin are keratinizing malignant tumors. Each SCC generally has some of the following features (FIGURE 11):

• dotted and/or glomerular vessels, commonly distributed focally at the periphery. They can also be diffuse or aligned linearly within the lesion.
• scale (yellow or white)
• rosettes (seen with polarized light)
• white circles or keratin pearls
• brown circles
• ulcerations
• brown dots or globules arranged in a linear configuration.

Continue to: Step 2...

Step 2: It’s melanocytic, but is it a nevus or a melanoma?

If, by following Step 1 of the algorithm, the lesion is determined to be of melanocytic origin, then one proceeds to Step 2 to decide whether the growth is a nevus, a suspicious lesion, or a melanoma. For this purpose, several additional algorithms are available.^12-17

Benign nevi tend to manifest with 1 of the following 10 patterns: (FIGURE 12)

1. diffuse reticular
2. patchy reticular
3. peripheral reticular with central hypopigmentation
4. peripheral reticular with central hyperpigmentation
5. homogeneous
6. peripheral globules/starburst. It has been suggested that lesions that show starburst morphology on dermoscopy require complete excision and follow-up since 13% of Spitzoid-looking symmetric lesions in patients older than 12 years were found to be melanoma in one study.¹⁸
7. peripheral reticular with central globules
8. globular
9. 2-component
10. symmetric multicomponent (this pattern should be interpreted with caution, and a biopsy is probably warranted for dermoscopic novices).

Melanomas tend to deviate from the benign patterns described earlier. Structures in melanomas are often distributed in an asymmetric fashion (which is the basis for diagnosis in many of the other algorithms), and most of them will reveal 1 or more of the melanoma-specific structures (FIGURE 13). The melanomas in FIGURES 14 A-H each show at least 2 melanoma-specific structures. On the face or sun-damaged skin, melanoma may present with grey color, a circle-in-circle pattern, and/or polygonal lines (FIGURE 15). Note that melanoma on the soles or palms may present with a parallel ridge pattern (FIGURE 16).

How to proceed after the evaluation of melanocytic lesions

After evaluating the lesion for benign patterns and melanoma-specific structures, there are 3 possible pathways:

1. The lesion adheres to one of the nevi patterns and does not display a melanoma-specific structure. You can reassure the patient that the lesion is benign.

2. The lesion:

A. Adheres to one nevus pattern, but also displays a melanoma-specific structure.

B. Does not adhere to any of the benign patterns and does not have any melanoma-specific structures.

This is considered a suspicious lesion, and the choices of action include performing a biopsy or short-term monitoring by comparing dermoscopic images over a 3-month interval. (Caveat: Never monitor raised lesions because nodular melanomas can grow quickly and develop a worsened prognosis in a short time. Instead you’ll want to biopsy the lesion that day or very soon thereafter.)

3. The lesion deviates from the benign patterns and has at least 1 melanoma-specific structure. Biopsy the lesion to rule out melanoma.

Continue to: A bonus...

Increasingly, dermoscopy is being used in the diagnosis of many other skin, nail, and hair problems. In fact, one great bonus to owning a dermatoscope is the accurate diagnosis of scabies. Dermoscopy can be helpful in detecting the scabies mite without having to scrape and use the microscope. Moreover, the sensitivity and specificity of a dermoscopic diagnosis is higher than for scraping and microscopy.¹⁹

What you’ll see

The anterior legs and mouth parts of the mite resemble a triangle (arrowhead, delta-wing jet) (FIGURE 17). Look for a burrow, and the mite can be seen at the end of the burrow as a faint circle with a leading darker triangle. The burrow itself has a distinctive pattern that has more morphology than an excoriation and has been described as the contrail of a jet plane. Using a dermatoscope attached to your smartphone allows you to magnify the image even further while maintaining a safe distance from the mite.

Dermoscopy, the use of a handheld instrument to magnify the skin 10-fold while providing a light source, is a quick, useful, cost-effective tool for detecting melanoma in family medicine.^1-4 The device, which allows the physician to visualize structures below the stratum corneum that are not routinely discernible with the naked eye, can be attached to a smartphone so that photos can be taken and reviewed with the patient. The photo can also be reviewed after a biopsy result is obtained.

Its use among non-dermatologist US physicians appears to be relatively low, but rising. One small study of physicians working in family medicine, internal medicine, and plastic surgery found that only 15% had ever used a dermatoscope and 6% were currently using one.⁵

As a family physician, you can expand your diagnostic abilities in dermatology with the acquisition of a dermatoscope (FIGURE 1) and some time invested in learning to interpret visible patterns. With that in mind, this review focuses on the diagnosis of skin cancers and benign growths using dermoscopy. We begin with a brief look at the research on dermoscopy and how it is performed. From there, we’ll detail an algorithm to guide dermoscopic analysis. And to round things out, we provide guidance that will help you to get started. (See “Choosing a dermatoscope—and making the most of it,” and “To learn more about dermoscopy …”.)

Continue to: What the research says

Dermoscopy improves sensitivity for detecting melanoma over the naked eye alone; it also allows for the detection of melanoma at earlier stages, which improves prognosis.⁶

A meta-analysis of dermoscopy use in clinical settings showed that, following training, dermoscopy increases the average sensitivity of melanoma diagnosis from 71% to more than 90% without a significant decrease in specificity.⁷ In a study of 74 primary care physicians, there was an improvement in both clinical and dermoscopic diagnosis of melanoma among those who received training in dermoscopy, compared with a control group.⁸ Another study found that primary care physicians can reduce their baseline benign-to-melanoma ratio (the number of suspicious benign lesions biopsied to find 1 melanoma) from 9.5:1 with naked eye examination to 3.5:1 with dermoscopy.⁹

The exam begins by choosing 1 of 3 modes of dermoscopy

Dermatoscopes can have a polarized or nonpolarized light source. Some dermatoscopes combine both types of light (hybrid dermatoscopes; see “Choosing a dermatoscope—and making the most of it.”)

There are 3 modes of dermoscopy:

1. nonpolarized contact dermoscopy
2. polarized contact dermoscopy
3. polarized non-contact dermoscopy.

Dermatoscopes with nonpolarized light require direct skin contact and a liquid interface (eg, alcohol, gel, mineral oil) between the scope’s glass plate and the skin for the visualization of subsurface structures. In contrast, dermatoscopes with polarized light do not require direct skin contact or a liquid interface; however, contacting the skin and using a liquid interface will provide a sharper image.

Continue to: Two major algorithms guide dermoscopic analysis

The first of 2 major algorithms that can be used to guide dermoscopic analysis is a modified pattern analysis put forth by Kittler.¹⁰ This descriptive system based on geometric elements, patterns, colors, and clues guides the observer to a specific diagnosis without categorizing lesions as being either melanocytic or nonmelanocytic. Because this is not the preferred method of the authors, we will move on to Method 2.

The second method, a 2-step algorithm, is a qualitative system that guides the observer through differentiating melanocytic from nonmelanocytic lesions in order to differentiate nevi from melanoma (FIGURE 2). At the same time, it serves as an aid to correctly diagnose non-melanocytic lesions. The 2-step algorithm forms the foundation for the dermoscopic evaluation of skin lesions in this article.

Not all expert dermoscopists employ structured analytical systems or methods to reach a diagnosis. Because of their vast experience, many rely purely on pattern recognition. But algorithms can facilitate non-experts in dermoscopy in the differentiation of nevi from melanoma or, simply, in differentiating the benign from the malignant.

Although each algorithm has its unique criteria, all of them require training and practice and familiarity with the terms used to describe morphologic structures. The International Dermoscopy Society recently published a consensus paper designating some terms as preferred over others.¹¹

Continue to: Step 1...

Step 1 of the 2-step algorithm requires the observer to determine whether the lesion is melanocytic (ie, originates from melanocytes and, therefore, could be a melanoma) or nonmelanocytic in origin.

A melanocytic lesion usually will display at least 1 of the following structures:

• pigment network (FIGURE 3A) (This can include angulated lines.)
• negative network (FIGURE 3B) (hypopigmented lines connecting pigmented structures in a serpiginous fashion)
• streaks (FIGURE 3C)
• homogeneous blue pigmentation (FIGURE 3D)
• globules (aggregated or as a peripheral rim) (FIGURE 3E)
• pseudonetwork (facial skin) (FIGURE 3F)
• parallel pigment pattern (acral lesions) (FIGURE 3G).

Exceptions. Sometimes, nonmelanocytic lesions will present with pigment network. Dermatofibromas, for example, are one exception in which the pattern trumps the network. Two other exceptions are solar lentigo and supernumerary or accessory nipple.

If the lesion does not display any structure, it is considered structureless. In these cases, proceed to the second step to rule out a melanoma.

Doesn’t meet criteria for a melanocytic lesion?

If the lesion does not reveal any of the criteria for a melanocytic lesion, then look for structures seen in nonmelanocytic lesions: dermatofibromas; seborrheic keratosis; angiomas and angiokeratomas; sebaceous hyperplasia; clear-cell acanthomas; basal cell carcinomas (BCCs); and squamous cell carcinomas (SCCs).

Continue to: Benign nonmelanocytic lesions

Dermatofibromas are benign symmetric lesions that feel firm and may dimple upon application of lateral pressure. They are fibrotic scar-like lesions that present with 1 or more of the following dermoscopic features (FIGURE 4):

• peripheral pigment network, due to increased melanin in keratinocytes
• homogeneous brown pigmented areas
• central scar-like area
• shiny white lines
• vascular structures (ie, dotted, polymorphous vessels), usually seen within the scar-like area
• ring-like globules, usually seen in the zone between the scar-like depigmentation and the peripheral network. They correspond to widened hyperpigmented rete ridges.

Seborrheic keratosis (SK) is a benign skin growth that often has a stuck-on appearance (FIGURE 5). Features often include:

• multiple (>2) milia-like cysts
• comedo-like openings
• a network-like structure that corresponds to gyri and sulci and which in some cases can create a cerebriform pattern
• fingerprint-like structures
• moth-eaten borders
• jelly sign. This consists of semicircular u-shaped structures that have a smudged appearance and are aligned in the same direction. The appearance resembles jelly as it is spread on a piece of bread.
• hairpin (looped or twisted-looped) vessels surrounded by a white halo.

Other clues include a sharp demarcation and a negative wobble sign (which we’ll describe in a moment). The presence or absence of a wobble sign is determined by using a dermatoscope that touches the skin. Mild vertical pressure is applied to the lesion while moving the scope back and forth horizontally. If the lesion slides across the skin surface, the diagnosis of an epidermal keratinocytic tumor (ie, SK) is favored. If, on the other hand, the lesion wobbles (rolls back and forth), then the diagnosis of a neoplasm with a dermal component (ie, intradermal or compound nevus) is more likely.

Angiomas and angiokeratomas. Angiomas demonstrate lacunae that are often separated by septae (FIGURE 6). Lacunae can vary in size and color. They can be red, red-white, red-blue, maroon, blue, blue-black, or even black (when thrombosis is present).

Angiokeratomas (FIGURE 7) can reveal lacunae of varying colors including black, red, purple, and maroon. In addition, a blue-whitish veil, erythema, and hemorrhagic crusts can be present.

Continue to: Sebaceous hyperplasia...

Sebaceous hyperplasia is the overgrowth of sebaceous glands. It can mimic BCC on the face. Sebaceous hyperplasia presents with multiple vessels in a crown-like arrangement that do not cross the center of the lesion. The sebaceous glands resemble popcorn (FIGURE 8).

Clear-cell acanthoma is a benign erythematous epidermal tumor usually found on the leg with a string-of-pearls pattern. This pattern is vascular so the pearls are red in color (FIGURE 9).

Malignant nonmelanocytic lesions

BCC is the most common type of skin cancer. Features often include:

• spoke-wheel-like structures or concentric structures (FIGURE 10A)
• leaf-like areas (FIGURE 10B)
• arborizing vessels (FIGURE 10b and 10C)large blue-gray ovoid nest (FIGURE 10A)
• multiple blue-gray non-aggregated globules
• ulceration or multiple small erosions
• shiny white structures and strands (FIGURE 10C).

Additional dermoscopic clues include short, fine, superficial telangiectasias and multiple in-focus dots in a buck-shot scatter distribution.

Squamous cell carcinomas (SCCs) of the skin are keratinizing malignant tumors. Each SCC generally has some of the following features (FIGURE 11):

• dotted and/or glomerular vessels, commonly distributed focally at the periphery. They can also be diffuse or aligned linearly within the lesion.
• scale (yellow or white)
• rosettes (seen with polarized light)
• white circles or keratin pearls
• brown circles
• ulcerations
• brown dots or globules arranged in a linear configuration.

Continue to: Step 2...

Step 2: It’s melanocytic, but is it a nevus or a melanoma?

If, by following Step 1 of the algorithm, the lesion is determined to be of melanocytic origin, then one proceeds to Step 2 to decide whether the growth is a nevus, a suspicious lesion, or a melanoma. For this purpose, several additional algorithms are available.^12-17

Benign nevi tend to manifest with 1 of the following 10 patterns: (FIGURE 12)

1. diffuse reticular
2. patchy reticular
3. peripheral reticular with central hypopigmentation
4. peripheral reticular with central hyperpigmentation
5. homogeneous
6. peripheral globules/starburst. It has been suggested that lesions that show starburst morphology on dermoscopy require complete excision and follow-up since 13% of Spitzoid-looking symmetric lesions in patients older than 12 years were found to be melanoma in one study.¹⁸
7. peripheral reticular with central globules
8. globular
9. 2-component
10. symmetric multicomponent (this pattern should be interpreted with caution, and a biopsy is probably warranted for dermoscopic novices).

Melanomas tend to deviate from the benign patterns described earlier. Structures in melanomas are often distributed in an asymmetric fashion (which is the basis for diagnosis in many of the other algorithms), and most of them will reveal 1 or more of the melanoma-specific structures (FIGURE 13). The melanomas in FIGURES 14 A-H each show at least 2 melanoma-specific structures. On the face or sun-damaged skin, melanoma may present with grey color, a circle-in-circle pattern, and/or polygonal lines (FIGURE 15). Note that melanoma on the soles or palms may present with a parallel ridge pattern (FIGURE 16).

How to proceed after the evaluation of melanocytic lesions

After evaluating the lesion for benign patterns and melanoma-specific structures, there are 3 possible pathways:

1. The lesion adheres to one of the nevi patterns and does not display a melanoma-specific structure. You can reassure the patient that the lesion is benign.

2. The lesion:

A. Adheres to one nevus pattern, but also displays a melanoma-specific structure.

B. Does not adhere to any of the benign patterns and does not have any melanoma-specific structures.

This is considered a suspicious lesion, and the choices of action include performing a biopsy or short-term monitoring by comparing dermoscopic images over a 3-month interval. (Caveat: Never monitor raised lesions because nodular melanomas can grow quickly and develop a worsened prognosis in a short time. Instead you’ll want to biopsy the lesion that day or very soon thereafter.)

3. The lesion deviates from the benign patterns and has at least 1 melanoma-specific structure. Biopsy the lesion to rule out melanoma.

Continue to: A bonus...

Increasingly, dermoscopy is being used in the diagnosis of many other skin, nail, and hair problems. In fact, one great bonus to owning a dermatoscope is the accurate diagnosis of scabies. Dermoscopy can be helpful in detecting the scabies mite without having to scrape and use the microscope. Moreover, the sensitivity and specificity of a dermoscopic diagnosis is higher than for scraping and microscopy.¹⁹

What you’ll see

The anterior legs and mouth parts of the mite resemble a triangle (arrowhead, delta-wing jet) (FIGURE 17). Look for a burrow, and the mite can be seen at the end of the burrow as a faint circle with a leading darker triangle. The burrow itself has a distinctive pattern that has more morphology than an excoriation and has been described as the contrail of a jet plane. Using a dermatoscope attached to your smartphone allows you to magnify the image even further while maintaining a safe distance from the mite.

Dermoscopy, the use of a handheld instrument to magnify the skin 10-fold while providing a light source, is a quick, useful, cost-effective tool for detecting melanoma in family medicine.^1-4 The device, which allows the physician to visualize structures below the stratum corneum that are not routinely discernible with the naked eye, can be attached to a smartphone so that photos can be taken and reviewed with the patient. The photo can also be reviewed after a biopsy result is obtained.

Its use among non-dermatologist US physicians appears to be relatively low, but rising. One small study of physicians working in family medicine, internal medicine, and plastic surgery found that only 15% had ever used a dermatoscope and 6% were currently using one.⁵

As a family physician, you can expand your diagnostic abilities in dermatology with the acquisition of a dermatoscope (FIGURE 1) and some time invested in learning to interpret visible patterns. With that in mind, this review focuses on the diagnosis of skin cancers and benign growths using dermoscopy. We begin with a brief look at the research on dermoscopy and how it is performed. From there, we’ll detail an algorithm to guide dermoscopic analysis. And to round things out, we provide guidance that will help you to get started. (See “Choosing a dermatoscope—and making the most of it,” and “To learn more about dermoscopy …”.)

Continue to: What the research says

Dermoscopy improves sensitivity for detecting melanoma over the naked eye alone; it also allows for the detection of melanoma at earlier stages, which improves prognosis.⁶

A meta-analysis of dermoscopy use in clinical settings showed that, following training, dermoscopy increases the average sensitivity of melanoma diagnosis from 71% to more than 90% without a significant decrease in specificity.⁷ In a study of 74 primary care physicians, there was an improvement in both clinical and dermoscopic diagnosis of melanoma among those who received training in dermoscopy, compared with a control group.⁸ Another study found that primary care physicians can reduce their baseline benign-to-melanoma ratio (the number of suspicious benign lesions biopsied to find 1 melanoma) from 9.5:1 with naked eye examination to 3.5:1 with dermoscopy.⁹

The exam begins by choosing 1 of 3 modes of dermoscopy

Dermatoscopes can have a polarized or nonpolarized light source. Some dermatoscopes combine both types of light (hybrid dermatoscopes; see “Choosing a dermatoscope—and making the most of it.”)

There are 3 modes of dermoscopy:

1. nonpolarized contact dermoscopy
2. polarized contact dermoscopy
3. polarized non-contact dermoscopy.

Dermatoscopes with nonpolarized light require direct skin contact and a liquid interface (eg, alcohol, gel, mineral oil) between the scope’s glass plate and the skin for the visualization of subsurface structures. In contrast, dermatoscopes with polarized light do not require direct skin contact or a liquid interface; however, contacting the skin and using a liquid interface will provide a sharper image.

Continue to: Two major algorithms guide dermoscopic analysis

The first of 2 major algorithms that can be used to guide dermoscopic analysis is a modified pattern analysis put forth by Kittler.¹⁰ This descriptive system based on geometric elements, patterns, colors, and clues guides the observer to a specific diagnosis without categorizing lesions as being either melanocytic or nonmelanocytic. Because this is not the preferred method of the authors, we will move on to Method 2.

The second method, a 2-step algorithm, is a qualitative system that guides the observer through differentiating melanocytic from nonmelanocytic lesions in order to differentiate nevi from melanoma (FIGURE 2). At the same time, it serves as an aid to correctly diagnose non-melanocytic lesions. The 2-step algorithm forms the foundation for the dermoscopic evaluation of skin lesions in this article.

Not all expert dermoscopists employ structured analytical systems or methods to reach a diagnosis. Because of their vast experience, many rely purely on pattern recognition. But algorithms can facilitate non-experts in dermoscopy in the differentiation of nevi from melanoma or, simply, in differentiating the benign from the malignant.

Although each algorithm has its unique criteria, all of them require training and practice and familiarity with the terms used to describe morphologic structures. The International Dermoscopy Society recently published a consensus paper designating some terms as preferred over others.¹¹

Continue to: Step 1...

Step 1 of the 2-step algorithm requires the observer to determine whether the lesion is melanocytic (ie, originates from melanocytes and, therefore, could be a melanoma) or nonmelanocytic in origin.

A melanocytic lesion usually will display at least 1 of the following structures:

• pigment network (FIGURE 3A) (This can include angulated lines.)
• negative network (FIGURE 3B) (hypopigmented lines connecting pigmented structures in a serpiginous fashion)
• streaks (FIGURE 3C)
• homogeneous blue pigmentation (FIGURE 3D)
• globules (aggregated or as a peripheral rim) (FIGURE 3E)
• pseudonetwork (facial skin) (FIGURE 3F)
• parallel pigment pattern (acral lesions) (FIGURE 3G).

Exceptions. Sometimes, nonmelanocytic lesions will present with pigment network. Dermatofibromas, for example, are one exception in which the pattern trumps the network. Two other exceptions are solar lentigo and supernumerary or accessory nipple.

If the lesion does not display any structure, it is considered structureless. In these cases, proceed to the second step to rule out a melanoma.

Doesn’t meet criteria for a melanocytic lesion?

If the lesion does not reveal any of the criteria for a melanocytic lesion, then look for structures seen in nonmelanocytic lesions: dermatofibromas; seborrheic keratosis; angiomas and angiokeratomas; sebaceous hyperplasia; clear-cell acanthomas; basal cell carcinomas (BCCs); and squamous cell carcinomas (SCCs).

Continue to: Benign nonmelanocytic lesions

Dermatofibromas are benign symmetric lesions that feel firm and may dimple upon application of lateral pressure. They are fibrotic scar-like lesions that present with 1 or more of the following dermoscopic features (FIGURE 4):

• peripheral pigment network, due to increased melanin in keratinocytes
• homogeneous brown pigmented areas
• central scar-like area
• shiny white lines
• vascular structures (ie, dotted, polymorphous vessels), usually seen within the scar-like area
• ring-like globules, usually seen in the zone between the scar-like depigmentation and the peripheral network. They correspond to widened hyperpigmented rete ridges.

Seborrheic keratosis (SK) is a benign skin growth that often has a stuck-on appearance (FIGURE 5). Features often include:

• multiple (>2) milia-like cysts
• comedo-like openings
• a network-like structure that corresponds to gyri and sulci and which in some cases can create a cerebriform pattern
• fingerprint-like structures
• moth-eaten borders
• jelly sign. This consists of semicircular u-shaped structures that have a smudged appearance and are aligned in the same direction. The appearance resembles jelly as it is spread on a piece of bread.
• hairpin (looped or twisted-looped) vessels surrounded by a white halo.

Other clues include a sharp demarcation and a negative wobble sign (which we’ll describe in a moment). The presence or absence of a wobble sign is determined by using a dermatoscope that touches the skin. Mild vertical pressure is applied to the lesion while moving the scope back and forth horizontally. If the lesion slides across the skin surface, the diagnosis of an epidermal keratinocytic tumor (ie, SK) is favored. If, on the other hand, the lesion wobbles (rolls back and forth), then the diagnosis of a neoplasm with a dermal component (ie, intradermal or compound nevus) is more likely.

Angiomas and angiokeratomas. Angiomas demonstrate lacunae that are often separated by septae (FIGURE 6). Lacunae can vary in size and color. They can be red, red-white, red-blue, maroon, blue, blue-black, or even black (when thrombosis is present).

Angiokeratomas (FIGURE 7) can reveal lacunae of varying colors including black, red, purple, and maroon. In addition, a blue-whitish veil, erythema, and hemorrhagic crusts can be present.

Continue to: Sebaceous hyperplasia...

Sebaceous hyperplasia is the overgrowth of sebaceous glands. It can mimic BCC on the face. Sebaceous hyperplasia presents with multiple vessels in a crown-like arrangement that do not cross the center of the lesion. The sebaceous glands resemble popcorn (FIGURE 8).

Clear-cell acanthoma is a benign erythematous epidermal tumor usually found on the leg with a string-of-pearls pattern. This pattern is vascular so the pearls are red in color (FIGURE 9).

Malignant nonmelanocytic lesions

BCC is the most common type of skin cancer. Features often include:

• spoke-wheel-like structures or concentric structures (FIGURE 10A)
• leaf-like areas (FIGURE 10B)
• arborizing vessels (FIGURE 10b and 10C)large blue-gray ovoid nest (FIGURE 10A)
• multiple blue-gray non-aggregated globules
• ulceration or multiple small erosions
• shiny white structures and strands (FIGURE 10C).

Additional dermoscopic clues include short, fine, superficial telangiectasias and multiple in-focus dots in a buck-shot scatter distribution.

Squamous cell carcinomas (SCCs) of the skin are keratinizing malignant tumors. Each SCC generally has some of the following features (FIGURE 11):

• dotted and/or glomerular vessels, commonly distributed focally at the periphery. They can also be diffuse or aligned linearly within the lesion.
• scale (yellow or white)
• rosettes (seen with polarized light)
• white circles or keratin pearls
• brown circles
• ulcerations
• brown dots or globules arranged in a linear configuration.

Continue to: Step 2...

Step 2: It’s melanocytic, but is it a nevus or a melanoma?

If, by following Step 1 of the algorithm, the lesion is determined to be of melanocytic origin, then one proceeds to Step 2 to decide whether the growth is a nevus, a suspicious lesion, or a melanoma. For this purpose, several additional algorithms are available.^12-17

Benign nevi tend to manifest with 1 of the following 10 patterns: (FIGURE 12)

1. diffuse reticular
2. patchy reticular
3. peripheral reticular with central hypopigmentation
4. peripheral reticular with central hyperpigmentation
5. homogeneous
6. peripheral globules/starburst. It has been suggested that lesions that show starburst morphology on dermoscopy require complete excision and follow-up since 13% of Spitzoid-looking symmetric lesions in patients older than 12 years were found to be melanoma in one study.¹⁸
7. peripheral reticular with central globules
8. globular
9. 2-component
10. symmetric multicomponent (this pattern should be interpreted with caution, and a biopsy is probably warranted for dermoscopic novices).

Melanomas tend to deviate from the benign patterns described earlier. Structures in melanomas are often distributed in an asymmetric fashion (which is the basis for diagnosis in many of the other algorithms), and most of them will reveal 1 or more of the melanoma-specific structures (FIGURE 13). The melanomas in FIGURES 14 A-H each show at least 2 melanoma-specific structures. On the face or sun-damaged skin, melanoma may present with grey color, a circle-in-circle pattern, and/or polygonal lines (FIGURE 15). Note that melanoma on the soles or palms may present with a parallel ridge pattern (FIGURE 16).

How to proceed after the evaluation of melanocytic lesions

After evaluating the lesion for benign patterns and melanoma-specific structures, there are 3 possible pathways:

1. The lesion adheres to one of the nevi patterns and does not display a melanoma-specific structure. You can reassure the patient that the lesion is benign.

2. The lesion:

A. Adheres to one nevus pattern, but also displays a melanoma-specific structure.

B. Does not adhere to any of the benign patterns and does not have any melanoma-specific structures.

This is considered a suspicious lesion, and the choices of action include performing a biopsy or short-term monitoring by comparing dermoscopic images over a 3-month interval. (Caveat: Never monitor raised lesions because nodular melanomas can grow quickly and develop a worsened prognosis in a short time. Instead you’ll want to biopsy the lesion that day or very soon thereafter.)

3. The lesion deviates from the benign patterns and has at least 1 melanoma-specific structure. Biopsy the lesion to rule out melanoma.

Continue to: A bonus...

Increasingly, dermoscopy is being used in the diagnosis of many other skin, nail, and hair problems. In fact, one great bonus to owning a dermatoscope is the accurate diagnosis of scabies. Dermoscopy can be helpful in detecting the scabies mite without having to scrape and use the microscope. Moreover, the sensitivity and specificity of a dermoscopic diagnosis is higher than for scraping and microscopy.¹⁹

What you’ll see

The anterior legs and mouth parts of the mite resemble a triangle (arrowhead, delta-wing jet) (FIGURE 17). Look for a burrow, and the mite can be seen at the end of the burrow as a faint circle with a leading darker triangle. The burrow itself has a distinctive pattern that has more morphology than an excoriation and has been described as the contrail of a jet plane. Using a dermatoscope attached to your smartphone allows you to magnify the image even further while maintaining a safe distance from the mite.

A 49-year-old Hispanic woman presented with a 4-month history of scaling and a macerated rash localized between her toes (FIGURE 1). The rash was malodorous, mildly erythematous, and sometimes associated with pruritus. The patient had no relevant medical history. Potassium hydroxide (KOH) testing was performed and found to be negative. So a Wood’s lamp was used to examine the patient’s toes—and it revealed the diagnosis.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

The Wood’s lamp revealed a coral-red fluorescence in the interdigital spaces (FIGURE 2), which led us to a diagnosis of erythrasma.

The coral-red fluorescence seen under the Wood’s lamp is due to porphyrins produced by Corynebacterium minutissimum. The organism invades the stratum corneum where it proliferates and causes erythrasma. Erythrasma typically appears as delineated, dry, red-brown patches in intertriginous areas, such as the axilla, groin, interdigital spaces, intergluteal cleft, perianal skin, and inframammary area.^1,2

Interdigital erythrasma is more common than previously thought; in one study of 151 patients with erythrasma, the most common site was the toe webs (64.9%), followed by the inguinal region (17.9%), the axillary region (14.6%), and the inframammary region (2.6%).² Erythrasma affects 4% of the population; risk factors include poor hygiene, hyperhidrosis, obesity, warm climate, diabetes, and an immunocompromised state.³

Differential includes “athlete’s foot”

The differential diagnosis for a pruritic rash between the toes includes:

Tinea pedis. Erythrasma is often mistaken for tinea pedis, because both conditions cause scaling between the toes. A Wood’s lamp exam can quickly differentiate between the 2,¹ as tinea pedis does not fluoresce under ultraviolet light.

Contact dermatitis mimics many conditions, but a negative Wood’s lamp exam and history of worsening with contact to specific substances helps to make this diagnosis.

Prevention and Tx hinge on good hygiene, topical agents

First-line management of erythrasma includes both nonpharmacologic and pharmacologic modalities. Good hygiene and, depending on the area affected, loose-fitting cotton undergarments can help treat and prevent erythrasma.

Topical 2% miconazole bid for 2 weeks has resulted in clearance rates as high as 88%.⁴ Its affordable price, over-the-counter availability, and lack of adverse effects make miconazole a reasonable choice.^4,5 It is also a smart treatment choice when erythrasma is coexisting with tinea, because it can treat both conditions. This is not uncommon in the interdigital spaces between the toes and in the groin.

Topical 1% clindamycin or 2% erythromycin solution or gel bid for 2 weeks can also be used to treat the condition.^3,6 However, given that topical antibiotics are more expensive than single-dose oral treatment and are no better than the oral formulations of these antibiotics,⁶ clarithromycin 1 g taken once orally may be preferred.^2,6

Our patient was treated with a single dose of clarithromycin 1 g. At follow-up, her erythrasma was clear.

CORRESPONDENCE
Richard P. Usatine, MD, University of Texas Health at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229; Usatine@uthscsa.edu.

A 49-year-old Hispanic woman presented with a 4-month history of scaling and a macerated rash localized between her toes (FIGURE 1). The rash was malodorous, mildly erythematous, and sometimes associated with pruritus. The patient had no relevant medical history. Potassium hydroxide (KOH) testing was performed and found to be negative. So a Wood’s lamp was used to examine the patient’s toes—and it revealed the diagnosis.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

The Wood’s lamp revealed a coral-red fluorescence in the interdigital spaces (FIGURE 2), which led us to a diagnosis of erythrasma.

The coral-red fluorescence seen under the Wood’s lamp is due to porphyrins produced by Corynebacterium minutissimum. The organism invades the stratum corneum where it proliferates and causes erythrasma. Erythrasma typically appears as delineated, dry, red-brown patches in intertriginous areas, such as the axilla, groin, interdigital spaces, intergluteal cleft, perianal skin, and inframammary area.^1,2

Interdigital erythrasma is more common than previously thought; in one study of 151 patients with erythrasma, the most common site was the toe webs (64.9%), followed by the inguinal region (17.9%), the axillary region (14.6%), and the inframammary region (2.6%).² Erythrasma affects 4% of the population; risk factors include poor hygiene, hyperhidrosis, obesity, warm climate, diabetes, and an immunocompromised state.³

Differential includes “athlete’s foot”

The differential diagnosis for a pruritic rash between the toes includes:

Tinea pedis. Erythrasma is often mistaken for tinea pedis, because both conditions cause scaling between the toes. A Wood’s lamp exam can quickly differentiate between the 2,¹ as tinea pedis does not fluoresce under ultraviolet light.

Contact dermatitis mimics many conditions, but a negative Wood’s lamp exam and history of worsening with contact to specific substances helps to make this diagnosis.

Prevention and Tx hinge on good hygiene, topical agents

First-line management of erythrasma includes both nonpharmacologic and pharmacologic modalities. Good hygiene and, depending on the area affected, loose-fitting cotton undergarments can help treat and prevent erythrasma.

Topical 2% miconazole bid for 2 weeks has resulted in clearance rates as high as 88%.⁴ Its affordable price, over-the-counter availability, and lack of adverse effects make miconazole a reasonable choice.^4,5 It is also a smart treatment choice when erythrasma is coexisting with tinea, because it can treat both conditions. This is not uncommon in the interdigital spaces between the toes and in the groin.

Topical 1% clindamycin or 2% erythromycin solution or gel bid for 2 weeks can also be used to treat the condition.^3,6 However, given that topical antibiotics are more expensive than single-dose oral treatment and are no better than the oral formulations of these antibiotics,⁶ clarithromycin 1 g taken once orally may be preferred.^2,6

Our patient was treated with a single dose of clarithromycin 1 g. At follow-up, her erythrasma was clear.

CORRESPONDENCE
Richard P. Usatine, MD, University of Texas Health at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229; Usatine@uthscsa.edu.

A 49-year-old Hispanic woman presented with a 4-month history of scaling and a macerated rash localized between her toes (FIGURE 1). The rash was malodorous, mildly erythematous, and sometimes associated with pruritus. The patient had no relevant medical history. Potassium hydroxide (KOH) testing was performed and found to be negative. So a Wood’s lamp was used to examine the patient’s toes—and it revealed the diagnosis.

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

The Wood’s lamp revealed a coral-red fluorescence in the interdigital spaces (FIGURE 2), which led us to a diagnosis of erythrasma.

The coral-red fluorescence seen under the Wood’s lamp is due to porphyrins produced by Corynebacterium minutissimum. The organism invades the stratum corneum where it proliferates and causes erythrasma. Erythrasma typically appears as delineated, dry, red-brown patches in intertriginous areas, such as the axilla, groin, interdigital spaces, intergluteal cleft, perianal skin, and inframammary area.^1,2

Interdigital erythrasma is more common than previously thought; in one study of 151 patients with erythrasma, the most common site was the toe webs (64.9%), followed by the inguinal region (17.9%), the axillary region (14.6%), and the inframammary region (2.6%).² Erythrasma affects 4% of the population; risk factors include poor hygiene, hyperhidrosis, obesity, warm climate, diabetes, and an immunocompromised state.³

Differential includes “athlete’s foot”

The differential diagnosis for a pruritic rash between the toes includes:

Tinea pedis. Erythrasma is often mistaken for tinea pedis, because both conditions cause scaling between the toes. A Wood’s lamp exam can quickly differentiate between the 2,¹ as tinea pedis does not fluoresce under ultraviolet light.

Contact dermatitis mimics many conditions, but a negative Wood’s lamp exam and history of worsening with contact to specific substances helps to make this diagnosis.

Prevention and Tx hinge on good hygiene, topical agents

First-line management of erythrasma includes both nonpharmacologic and pharmacologic modalities. Good hygiene and, depending on the area affected, loose-fitting cotton undergarments can help treat and prevent erythrasma.

Topical 2% miconazole bid for 2 weeks has resulted in clearance rates as high as 88%.⁴ Its affordable price, over-the-counter availability, and lack of adverse effects make miconazole a reasonable choice.^4,5 It is also a smart treatment choice when erythrasma is coexisting with tinea, because it can treat both conditions. This is not uncommon in the interdigital spaces between the toes and in the groin.

Topical 1% clindamycin or 2% erythromycin solution or gel bid for 2 weeks can also be used to treat the condition.^3,6 However, given that topical antibiotics are more expensive than single-dose oral treatment and are no better than the oral formulations of these antibiotics,⁶ clarithromycin 1 g taken once orally may be preferred.^2,6

Our patient was treated with a single dose of clarithromycin 1 g. At follow-up, her erythrasma was clear.

CORRESPONDENCE
Richard P. Usatine, MD, University of Texas Health at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229; Usatine@uthscsa.edu.