UV light therapy is often used in cases refractory to topical therapy. Patients are typically prescribed 2 to 3 treatments per week with narrowband UVB (311-313 nm), the excimer laser (308 nm), or, less commonly, PUVA (UV treatment with psoralens). Treatment begins with a minimal erythema dose—the lowest dose to achieve minimal erythema of the skin before burning. When that is determined, exposure is increased as needed—depending on the response. If this is impractical or too time-consuming for the patient, an alternative recommendation would be increased exposure to natural sunlight or even use of a tanning booth. However, patients must then be cautioned about the increased risk of skin cancer.
Refractory/severe psoriasis
Patient B is a 35-year-old man with a longstanding history of psoriasis affecting his scalp and nails. Over the past 10 years, psoriatic lesions have also appeared and grown across his lower back, gluteal fold, legs, abdomen, and arms. He is now being evaluated by a rheumatologist for worsening symmetric joint pain that includes his lower back.
Methotrexate has been used to treat psoriasis and psoriatic arthritis since the 1950s. Methotrexate is a competitive inhibitor of dihydrofolate reductase and is typically given as an oral medication dosed once weekly with folic acid supplementation on the other 6 days.17 The most common adverse effects encountered with methotrexate are gastrointestinal upset and oral ulcers; however, routine monitoring for myelosuppression and hepatotoxicity is required.
Biologic therapy. When conventional therapies fail, immune-targeted treatment with “biologics” may be initiated. As knowledge of signaling pathways and the immunopathogenesis of psoriasis has increased, so has the number of biologic agents, which are generally well tolerated and effective in managing plaque psoriasis and psoriatic arthritis. Although their use, which requires monitoring, is handled primarily by specialists, familiarizing yourself with available agents can be helpful (TABLE).22
Nutritional modification and supplementation in treating skin disease still requires further investigation. Fish oil has shown benefit for cutaneous psoriasis in randomized controlled trials.7,8 Oral vitamin D supplementation requires further study, whereas selenium and B12 supplementation have not conferred consistent benefit.7 Given that several studies have demonstrated a relationship between body mass index and psoriatic disease severity, weight loss may be helpful in the management of psoriasis as well as psoriatic arthritis.8
Continue to: Other systemic agents