Clinical Review

Translating the 2019 AAD-NPF Guidelines of Care for the Management of Psoriasis With Phototherapy

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Psoralen plus UVA, which may be used topically (ie, bathwater PUVA) or taken orally, refers to treatment with photosensitizing psoralens. Psoralens are agents that intercalate with DNA and enhance the efficacy of phototherapy.10 Topical PUVA, with a grade B level of recommendation, is an effective treatment option for patients with localized disease and has been shown to be particularly efficacious in the treatment of palmoplantar pustular psoriasis. Oral PUVA is an effective option for psoriasis with a grade A recommendation, while bathwater PUVA has a grade B level of recommendation for moderate to severe plaque psoriasis. Oral PUVA is associated with greater systemic side effects (both acute and subacute) compared with NB-UVB and also is associated with photocarcinogenesis, particularly squamous cell carcinoma in white patients.11 Other side effects from PUVA include pigmented macules in sun-protected areas (known as PUVA lentigines), which may make evaluation of skin lesions challenging. Because of the increased risk for cancer with oral PUVA, NB-UVB is preferable as a first-line treatment vs PUVA, especially in patients with a history of skin cancer.12,13

Goeckerman therapy, which involves the synergistic combination of UVB and crude coal tar, is an older treatment that has shown efficacy in the treatment of severe or recalcitrant psoriasis (grade B level of recommendation). One prior case-control study comparing the efficacy of Goeckerman therapy with newer treatments, such as biologic therapies, steroids, and oral immunosuppressants, found a similar reduction in symptoms among both treatment groups, with longer disease-free periods in patients who received Goeckerman therapy than those who received newer therapies (22.3 years vs 4.6 months).14 However, Goeckerman therapy is utilized less frequently than more modern therapies because of the time required for treatment and declining insurance reimbursements for it. Climatotherapy, another older established therapy, involves the temporary or permanent relocation of patients to an environment that is favorable for disease control (grade B level of recommendation). Locations such as the Dead Sea and Canary Islands have been studied and shown to provide both subjective and objective improvement in patients’ psoriasis disease course. Patients had notable improvement in both their psoriasis area and severity index score and quality of life after a 3- to 4-week relocation to these areas.15,16 Access to climatotherapy and the transient nature of disease relief are apparent limitations of this treatment modality.

Grenz ray is a type of phototherapy that uses longer-wavelength ionizing radiation, which has low penetrance into surrounding tissues and a 95% absorption rate within the first 3 mm of the skin depth. This treatment has been used less frequently since the development of newer alternatives but should still be considered as a second line to UV therapy, especially in cases of recalcitrant disease and palmoplantar psoriasis, and when access to other treatment options is limited. Grenz ray has a grade C level of recommendation due to the paucity of evidence that supports its efficacy. Thus, it is not recommended as first-line therapy for the treatment of moderate to severe psoriasis. Visible light therapy is another treatment option that uses light in the visible wavelength spectrum but predominantly utilizes blue and red light. Psoriatic lesions are sensitive to light therapy because of the elevated levels of naturally occurring photosensitizing agents, called protoporphyrins, in these lesions.17 Several small studies have shown improvement in psoriatic lesions treated with visible light therapy, with blue light showing greater efficacy in lesional clearance than red light.18,19

Pulsed dye laser is a phototherapy modality that has shown efficacy in the treatment of nail psoriasis (grade B level of recommendation). One study comparing the effects of tazarotene cream 0.1% with pulsed dye laser and tazarotene cream 0.1% alone showed that patients receiving combination therapy had a greater decrease in nail psoriasis severity index scores, higher scores on the patient’s global assessment of improvement, and higher rates of improvement on the physician global assessment score. A physician global assessment score of 75% improvement or more was seen in patients treated with combination therapy vs monotherapy (5.3% vs 31.6%).20 Intense pulsed light, a type of visible light therapy, also has been used to treat nail psoriasis, with one study showing notable improvement in nail bed and matrix disease and a global improvement in nail psoriasis severity index score after 6 months of biweekly treatment.21 However, this treatment has a grade B level of recommendation given the limited number of studies supporting the efficacy of this modality.

Initiation of Phototherapy

Prior to initiating phototherapy, it is important to assess the patient for any personal or family history of skin cancer, as phototherapy carries an increased risk for cutaneous malignancy, especially in patients with a history of skin cancer.22,23 All patients also should be evaluated for their Fitzpatrick skin type, and the minimal erythema dose should be defined for those initiating UVB treatment. These classifications can be useful for the initial determination of treatment dose and the prevention of treatment-related adverse events (TRAEs). A careful drug history also should be taken before the initiation of phototherapy to avoid photosensitizing reactions. Thiazide diuretics and tetracyclines are 2 such examples of medications commonly associated with photosensitizing reactions.24

Fitzpatrick skin type and/or minimal erythema dose testing also are essential in determining the appropriate initial NB-UVB dose required for treatment initiation (Table 2). Patient response to the initial NB-UVB trial will determine the optimal dosage for subsequent maintenance treatments.

For patients unable or unwilling to commit to office-based or institution-based treatments, home NB-UVB is another therapeutic option. One study comparing patients with moderate to severe psoriasis who received home NB-UVB vs in-office treatment showed comparable psoriasis area and severity index scores and quality-of-life indices and no difference in the frequency of TRAE indices. It is important to note that patients who received home treatment had a significantly lower treatment burden (P≤.001) and greater treatment satisfaction than those receiving treatment in an office-based setting (P=.001).25

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