Polymorphous Light Eruption: a Review

Abstract

Purpose of Review: To update readers on the current understandings of polymorphous light eruption (PMLE) in regard to epidemiology, clinical findings, pathophysiology, treatment, and prognosis. Recent Findings: 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. Summary: 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.