Polymorphous light dermatosis. Clinical data and test results

: In a retrospective study, the clinical data of 424 patients, 340 (= 80.2%) female and 84 (= 19.8%) male, with polymorphous light eruption (PLE) were evaluated; 89.1% of the patients had skin type II or III (according to Fitzpatrick). 368 Photoprovocation testing was performed on 332 of these cases. The duration of PLE was (mean +/- SD) 7 +/- 6.9 years, and the age at onset of the disease was 28 +/- 14 years. In 40.1% of the patients PLE developed without seasonal accentuation. Predilection sites for skin lesions were the extensor aspects of the upper arm or forearm (69.0%/66.7%) and the chest (59.5%); the face and the back of the hand were less frequently (41.0%/40.8%) affected. In most cases (53.6%/18.3%), the skin lesions were papular or erythemato-urticarial in type. The minimal erythema dose for UV-B was found to be normal in all 311 cases in which it was assessed. Photoprovocation testing yielded skin lesions of PLE in 38.4% of the female, and in 58.5% of the male patients. The frequency of positive reactions to photoprovocation testing was directly related to the duration of the disease, the persistence of naturally occurring lesions, and the time interval from accidental exposure to the development of lesions.