Background: Polymorphous light eruption (PMLE) is the most common chronic idiopathic photodermatosis usually manifesting as a papular eruption (3-6 mm), with several other morphological variants described.
Methods: Between June 1998 and August 2001, nine patients presented with complaints of a pruritic pinpoint papular eruption associated with sun exposure. A detailed history and complete skin examination were performed along with a skin biopsy if active lesions were present. Phototesting to ultraviolet-A (UV-A), ultraviolet-B (UV-B) and visible light was performed in four patients. Antinuclear antibody (ANA) testing was performed in three patients. The diagnosis of PMLE was made based on the history, morphology of the lesions, results of phototesting and skin biopsy if available.
Results: In all patients, pinpoint papules (1-2 mm) were observed on sun-exposed areas, sparring the face and flexural surfaces. All patients were African American women with skin type IV-VI and a mean age of 39.3 years (range 21-52 years). Phototest results were normal in three patients; one patient, who was on glyburide, had a decreased minimal erythema dose to UV-A. ANA testing was negative. Two histopathologic patterns were observed: (i) focal lichenoid and perivascular lymphohistiocytic infiltrate with red blood cell extravasation in four specimens and (ii) superficial and deep interstitial lymphocytic infiltrate with papillary dermal edema in the remaining three specimens. All patients responded to topical corticosteroids, broad-spectrum sunscreens and antihistamines.
Conclusion: Recognition of this pinpoint papular variant of PMLE in dark-skinned individuals is important in the evaluation and management of these patients.