Document resource
A woman in her 60s with no known comorbidities presented with a 3-week history of multiple erythematous, pruritic, well-demarcated annular plaques over photoexposed areas of the forearms, V-area of the neck, upper chest and upper back. Notably, photoprotected areas were spared. The lesions were non-scaly with slightly raised erythematous borders and central clearing ( figure 1). The preliminary differential diagnoses included polymorphous light eruption and granuloma annulare. Other annular dermatoses considered in the differential diagnosis included tinea corporis, necrobiosis lipoidica, sarcoidosis and Hansen’s disease. While polymorphous light eruption typically presents with papulovesicular or eczematous lesions rather than annular plaques, it was initially considered due to the photodistributed nature of the eruption. A skin biopsy obtained by a local physician was misinterpreted as borderline Hansen’s disease. She was subsequently started on multidrug therapy (MDT), which resulted in no improvement over the next 3–4 months.