Disease associations in polymorphous light eruption - A long-term follow-up study of 94 patients

Objectives: To examine the long-term outcome of polymorphous light eruption (PIE) in a large patient population and to evaluate associated conditions, especially lupus erythematosus, during the course of the disease. Design: A questionnaire-based follow-up study an average of 32 years after onset of PLE. The study was complemented by clinical examination of the patients with PLE similarly studied 16 years earlier or now reporting equal or worse PLE symptoms compared with the 1978-1979 followup or any symptoms suggesting an autoimmune disease. Setting: A dermatologic clinic in a university hospital. Patients: Ninety-four of the original cohort of 138 patients with PIE (87% of living patients) returned the questionnaire, and 46 (84%) of the 55 patients invited volunteered for clinical examination. Intervention: None. Main Outcome Measures: Clinical characteristics of PLE and clinical and laboratory findings referring to associated diseases, especially lupus erythematosus. Results: Twenty-three (24%; 95% confidence interval [CI], 16%-34%) of the 94 patients were cured, 48 (51%; 95% CI, 41%-62%) experienced milder symptoms, and 23 (24%; 95% CI, 16%-34%) experienced equal or worse symptoms than in the 1978-1979 follow-up. At least 1 autoimmune disease was diagnosed at some point in 14 patients (15%; 95% CI, 12%-29%) (in 13 [18%] of the female patients) and lupus erythematosus specifically in 2 (2%; 95% CI, 0%-7%) (in 2 [3%] of the female patients). The prevalence of a thyroid disease was 14% (13 patients) (95% CI,8%-23%). Conclusion: Polymorphous light eruption is a longstanding, slowly ameliorating disease with some tendency to development of autoimmune disease or thyroid disorder, especially in female patients, but the risk for lupus erythematosus is not increased.