Clinical, laboratory phototest and phototherapy findings in polymorphic light eruption: a retrospective study of 133 patients

In the present study, we retrospectively evaluated the clinical, laboratory , phototest and phototherapy findings in 133 patients (109 females and 24 m ales) with polymorphic light eruption (PLE). The median age of the patients at onset of PLE was 26 years (range, 3-62 years). The median duration of P LE at presentation was 6.5 years (range, 1 week to 25 years). Interestingly , we found two peaks in the distribution curve of the individual latent int erval, the time between light exposure and the appearance of skin lesions. The first peak occurred at 1-1.5 hr and the second peak at 24 hrs after lig ht exposure. Six of 33 patients tested had antinuclear antibodies (ANA). Ho wever, none of these ANA-positive patients had or developed systemic lupus erythematosus during follow-up. Phototesting revealed that minimal erythema doses for UVA and UVB fell within normal limits in 30 patients tested. Pro vocative phototesting was positive in 17 of 30 (57%) patients tested. The a ction spectrum fell within the UVA range in 10 (59%), the UVB range in 4 (2 3%), and both ranges in 3 (18%) of the 17 cases. Ninety-two patients receiv ed preventive phototherapy including broad-band UVB, broad-band UVA, or pso ralen and ultraviolet A (PUVA). Follow-up information was available for 79 of these patients: the complete protection rate in the first summer season after therapy was 27% for UVB, 0% for UVA, and 53% for PUVA whereas the ove rall protection rate (including partial and complete responders) was 83% fo r UVA, 82% for UVB and 65% for PUVA. In contrast, the patients' histories r evealed that the use of a sunscreen with a mean sun protection factor (SPF) of 14 did not prevent skin lesions in 88% of PLE patients.