What are the most common acute UVB phototherapy side effects?

The most common acute side effect is a sunburn-like effect within 24 hours of treatment manifested by erythema and tenderness of the skin. When this occurs, therapy is usually withheld until the erythema fades, and the amount of UVB administered is usually reduced at the next treatment session. Patients who fail to wear eye protection that blocks UVB may develop corneal burns. Occasionally, patients with psoriasis may experience temporary pustular flares of psoriasis during treatment. Topical preparations used in conjunction with UVB phototherapy, such as emollients and tar, may produce a folliculitis. This complication can be prevented by instructing the patient to apply topical preparations in a downward fashion to prevent follicular irritation. A severe blistering burn is rare when UVB is properly administered, and may be associated with Koebner’s isomorphic phenomenon resulting in psoriatic plaques in the burned area of skin.