Polymorphous Light Eruption: a Review

Abstract

To update readers on the current understandings of polymorphous light eruption (PMLE) in regard to epidemiology, clinical findings, pathophysiology, treatment, and prognosis. PMLE is known to be the most common photodermatosis seen in individuals with light skin types; however, recent evidence shows that it is also commonly observed in individuals with skin of color. Resistance to UV-induced immunosuppression is now known to be an essential part of pathogenesis; this could be secondary to unique cytokine or antimicrobial peptide expressions in these patients. Photohardening, done at the onset of sunny season for patients living in temperate climate, is a commonly used and effective management. PMLE is the most common photodermatosis. Lesions occur within hours after sun exposure, varying from urticarial papules, pinhead papules, to vesicles; they resolve in days to weeks without scarring. Resistance to UV-induced immunosuppression is thought to be an important contributor to the pathophysiology. Management includes photoprotection and photohardening. A 7–10-day course of oral corticosteroids is an appropriate prophylaxis for patients who plan to go to sunny locale for vacation. Though PMLE is chronic, many patients show improvement over years.