Chronic vulvar purpura: Persistent pigmented purpuric dermatitis (lichen aureus) of the vulva or plasma cell (Zoon's) vulvitis?

Background: Lichen aureus is localized variant of persistent pigmented purpuric dermatitis that typically affects the legs and can be associated with delayed hypersensitivity reactions or vascular abnormalities. Plasma cell vulvitis (Zoon's vulvitis) is a rare condition that frequently contains hemosiderin deposits and is suspected to be a mucosal reaction pattern due to variety of insults, most often local irritation or trauma. Case Report: A 50-year-old female with longstanding complaints of spotting, vulvar dryness, irritation, and dyspareunia presented with circumscribed, purpuric, erythematous vulvar patches. Past estrogen cream treatment evoked symptoms of discomfort. On biopsy, siderophages and extravasated red blood cells were found in conjunction with a lichenoid, lymphocyte and plasma cell infiltrate, and dilated dermal and intraepithelial vessels. Conclusions: Reported herein is an unusual vulvar dermatosis that is best classified as a localized variant of persistent pigmented dermatosis (lichen aureus) but overlaps clinically and histologically with Zoon's vulvitis. This constellation of findings may represent a site-specific mucosal reaction to an erosive process that could either be inflammatory (hypersensitivity reaction) and/or traumatic in nature.