A 62-year-old woman presents for evaluation of a rash affecting both arms. The condition is somewhat itchy and the current outbreak has been present for 3 weeks. The eruption first appears in late spring following outdoor exposure and has followed a similar pattern over the course of several years. Examination reveals scattered erythematous patches and slightly elevated plaques on her upper extremities, with faint patches on her forehead and chest.
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Polymorphous light eruption (PMLE) is the most common idiopathic photodermatosis. PMLE is a recurrent, delayed reaction to sunlight, with symptoms ranging from erythematous papules, papulovesicles, and plaques to erythema multiforme-like lesions on sun-exposed areas.1 Only one clinical manifestation is observed within any one patient.
PMLE usually presents during the first 3 decades of life,2 and women are affected 2 to 3 times more frequently than men. A review of 280 patients with photodermatoses found a statistically significantly higher percentage of blacks with PMLE compared with whites.3
Prophylactic therapy with broad-spectrum high-SPF sunscreen, protective clothing, and sunlight avoidance are preventive measures. Smoking cessation should be encouraged because tobacco use may worsen the condition.4 Controlled phototherapy at the beginning of spring for several weeks may prevent flare-ups throughout the summer.5 When preventive measures fail and light therapy is ineffective or impractical, topical or oral steroids often provide relief. Other therapies that have been used successfully include antimalarial drugs, beta-carotene, nicotinamide, azathioprine, and thalidomide.6-8
Michael Stas, DPM, is a podiatry-dermatology fellow at St. Luke’s University Hospital in Bethlehem, Pennsylvania, and at the DermDox Dermatology Center in Hazleton, Pennsylvania. Stephen Schleicher, MD, is an associate professor of medicine at the Commonwealth Medical College in Scranton, Pennsylvania, and an adjunct assistant professor of dermatology at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia. He practices dermatology in Hazleton, Pennsylvania.
- Hönigsmann H. Polymorphous light eruption. Photodermatol Photoimmunol Photomed. 2008;24:155-161.
- Naleway AL, Greenlee RT, Melski JW. Characteristics of diagnosed polymorphous light eruption. Photodermatol Photoimmunol Photomed. 2006;22:205-207.
- Kerr HA, Lim HW. Photodermatoses in African Americans: a retrospective analysis of 135 patients over a 7-year period. J Am Acad Dermatol. 2007;57:638-643.
- Metelitsa AI, Lauzon GJ. Tobacco and the skin. Clin Dermatol. 2010;28:384-390.
- Murphy GM, Logan RA, Lovell CR, Morris RW, Hawk JL, Magnus IA. Prophylactic PUVA and UVB therapy in polymorphic light eruption—a controlled trial. Br J Dermatol. 1987;116:531-538.
- Jansén CT. Oral carotenoid treatment in polymorphous light eruption: A cross-over comparison with oxychloroquine and placebo. Photodermatol. 1985;2:166-169.
- Neumann R, Rappold E, Pohl-Markl H. Treatment of polymorphous light eruption with nicotinamide: a pilot study. Br J Dermatol. 1986;115:77-80.
- Norris PG, Hawk JL. Successful treatment of severe polymorphous light eruption with azathioprine. Arch Dermatol. 1989;125:1377-1379.