Clinical Review

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

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In July 2019, the American Academy of Dermatology (AAD) and the National Psoriasis Foundation (NPF) released an updated set of guidelines regarding the use of phototherapy to manage adult patients with psoriasis. Treatment with light of various wavelengths is reviewed, with a focus on modalities utilizing UV light. These guidelines provide the most up-to-date evidence regarding dosing, indications, contraindications, and adverse effects of phototherapy alone and in combination with other treatments for psoriasis. This review aims to present the recommendations in a form that is readily translatable to clinical practice.

Practice Points

  • Phototherapy should be considered as an effective and low-risk treatment of psoriasis.
  • Narrowband UVB, broadband UVB, targeted phototherapy (excimer laser and excimer lamp), and oral psoralen plus UVA have all received a grade A level of recommendation for the treatment of psoriasis in adults.



Psoriasis is a systemic immune-mediated disorder characterized by erythematous, scaly, well-demarcated plaques on the skin that affects approximately 3% of the world’s population.1 Although topical therapies often are the first-line treatment of mild to moderate psoriasis, approximately 1 in 6 individuals has moderate to severe disease that requires systemic treatment such as biologics or phototherapy.2 In patients with localized disease that is refractory to treatment or who have moderate to severe psoriasis requiring systemic treatment, phototherapy should be considered as a potential low-risk treatment option.

In July 2019, the American Academy of Dermatology (AAD) and National Psoriasis Foundation (NPF) released an updated set of guidelines for the use of phototherapy in treating adult patients with psoriasis.3 Since the prior guidelines were released in 2010, there have been numerous studies affirming the efficacy of phototherapy, with several large meta-analyses helping to refine clinical recommendations.4,5 Each treatment was ranked using Strength of Recommendation Taxonomy, with a score of A, B, or C based on the strength of the evidence supporting the given modality. With the ever-increasing number of treatment options for patients with psoriasis, these guidelines inform dermatologists of the recommendations for the initiation, maintenance, and optimization of phototherapy in the treatment of psoriasis.

The AAD-NPF recommendations discuss the mechanism of action, efficacy, safety, and frequency of adverse events of 10 commonly used phototherapy/photochemotherapy modalities. They also address dosing regimens, the potential to combine phototherapy with other therapies, and the efficacy of treatment modalities for different types of psoriasis.3 The purpose of this discussion is to present these guidelines in a condensed form for prescribers of phototherapy and to review the most clinically significant considerations during each step of treatment. Of note, we only highlight the treatment of adult patients and do not discuss information relevant to pediatric patients with psoriasis.

Choosing a Phototherapy Modality

Phototherapy may be considered for patients with psoriasis that affects more than 3% body surface area or for localized disease refractory to conventional treatments. UV light is believed to provide relief from psoriasis via multiple mechanisms, such as through favorable alterations in cytokine profiles, initiation of apoptosis, and local immunosupression.6 There is no single first-line phototherapeutic modality recommended for all patients with psoriasis. Rather, the decision to implement a particular modality should be individualized to the patient, considering factors such as percentage of body surface area affected by disease, quality-of-life assessment, comorbidities, lifestyle, and cost of treatment.

Of the 10 phototherapy modalities reviewed in these guidelines, 4 were ranked by the AAD and NPF as having grade A evidence for efficacy in the treatment of moderate to severe plaque psoriasis. Treatments with a grade A level of recommendation included narrowband UVB (NB-UVB), broadband UVB (BB-UVB), targeted phototherapy (excimer laser and excimer lamp), and oral psoralen plus UVA (PUVA) therapy. Photodynamic therapy for psoriasis was given an A-level recommendation against its use, as it was found to be ineffective with an unfavorable side-effect profile. Treatments with a grade B level of recommendation—nonoral routes of PUVA therapy, pulsed dye laser/intense pulsed light for nail psoriasis only, Goeckerman therapy, and climatotherapy—have sufficient evidence available to support their treatment of moderate to severe psoriasis in some cases. Treatments with a grade C level of recommendation—Grenz ray therapy (also called borderline or ultrasoft therapy) and visible light therapy—have insufficient evidence to support their use in patients with moderate to severe psoriasis (Table 1).

Studies have shown that the ideal wavelength needed to produce a therapeutic effect (ie, clearance of psoriatic plaques) is 304 to 313 nm. Wavelengths of 290 to 300 nm were found to be less therapeutic and more harmful, as they contributed to the development of sunburns.7 Broadband UVB phototherapy, with wavelengths ranging from 270 to 390 nm, exposes patients to a greater spectrum of radiation, thus making it more likely to cause sunburn and any theoretical form of sun-related damage, such as dysplasia and cancer. Compared with NB-UVB phototherapy, BB-UVB phototherapy is associated with a greater degree of sun damage–related side effects. Narrowband UVB, with a wavelength range of 311 to 313 nm, carries a grade A level of recommendation and should be considered as first-line monotherapy in patients with generalized plaque psoriasis, given its efficacy and promising safety profile. Multiple studies have shown that NB-UVB phototherapy is superior to BB-UVB phototherapy in the treatment of moderate to severe psoriasis in adults.8,9 In facilities where access to NB-UVB is limited, BB-UVB monotherapy is recommended as the treatment of generalized plaque psoriasis.


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