Treatment of polymorphous light eruption.

This study was designed in order to prove on a large-scale basis the efficacy of oral photochemotherapy (PUVA) in the prevention of polymorphous light eruption (PLE), to work out indication criteria for PUVA treatment of this disease, and to establish a simple method based on anamnestic data to differentiate UVA from UVB induced PLE. The results obtained in 106 PLE patients (85 UVA-, 21 UVB-induced) demonstrate that: 1) time consuming phototesting for determination of the disease's action spectrum is unnecessary for practical purposes; 2) PUVA-induced tanning under routine conditions represents a potent prophylaxis even in severe cases of PLE; and 3) topical sunscreens ("sunblockers") in the majority of cases are sufficient to protect UVB-promoted PLE, but fail in UVA-induced disease. PUVA thus seems the treatment of choice only in UVA-mediated PLE, the action spectrum of the disease at least in most cases being easily discovered from certain anamnestic data.