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Case Reports

Abstract

A 49-year-old woman presented to the dermatology clinic with a petechial rash of the bilateral lower legs, which had waxed and waned for several years. The lesions were mildly pruritic and non-blanchable, and there were orange-brown macules admixed with petechiae. Due to the patient’s history of primary Raynaud’s disease, she was referred to dermatology to evaluate for vasculitis. Punch biopsy of her right lateral shin revealed a granulomatous dermatitis with extravasated erythrocytes without evidence of vasculitis. Dermal mucin was not increased, lymphocytic cytologic atypia was not seen, and spirochete immunostain was negative. Considering the clinical presentation of a petechial rash on the lower legs, these histopathologic findings are consistent with a granulomatous variant of capillaritis or pigmented purpuric dermatosis (PPD). PPDs are a spectrum of chronic dermatitides that present as speckled brown, orange, or red lesions of the skin, generally occurring in middle-aged to elderly patients and commonly follow a chronic waxing and waning course. Lesions are usually found in a localized distribution on the legs. The histopathology of PPD typically is a superficial perivascular lymphocytic infiltrate with extravasated red blood cells, often with hemosiderin deposition, and no evidence of vasculitis. Granulomatous presentations of PPD are uncommon, and it is thought to be most associated with individuals of East Asian ethnicity and hyperlipidemia. However, cases have been described in patients outside these populations, such as ours who is Caucasian and does not have hyperlipidemia.