OCCURRENCE OF POLYMORPHOUS LIGHT ERUPTION IN LUPUS-ERYTHEMATOSUS

Photosensitivity is a well-known manifestation of lupus erythematosus (LE). Since there are no strict criteria for photosensitivity, varying prevalence figures have been reported. Also, distinction from polymor phous light eruption (PLE) can be difficult. The purpose of this study was to characterize photosensitivity in more detail and to determine the occurrence of PLE in a series of well-documented LE patients. A qu estionnaire was answered by 337 LE patients seen at dermatology depart ments in Finland and Sweden, and 63 of the patients were invited for i nterview. According to the questionnaire, LE lesions were made worse b y sunlight in 242 (72%) patients. Symptoms consistent with PLE were re ported by 165 (49%) patients. Detailed personal interviews supported t he results from the questionnaire, and revealed that PLE had started 2 -45 years before the onset of LE in 23 of 37 patients with both diagno ses, and more than 7 years before in 18 of 37 (49%). PLE proved to be common in patients with both systemic and cutaneous LE. The two condit ions may often coexist and, in about half of the cases, PLE preceded L E. These two diseases may share pathogenic factors, PLE might predispo se to LE in a subgroup of PLE patients.