Symptomatic vulvar demodicosis: A case report and review of the literature

Demodex folliculorum is a mite that commonly inhabits the pilosebaceous units of facial skin, particularly in a perioral and periorbital distribution. While typically an incidental and asymptomatic parasite, Demodex spp. are proposed to contribute to the pathogenesis of facial folliculitis, chronic blepharitis and papulopustular rosacea. Reports of demodicosis in anatomic locations other than the face are exceedingly rare. Here we report a 36-year-old woman with symptomatic Demodex spp. infestation of Fordyce spots of the labia minora. She was referred to dermatology after a 9-month history of tender red bumps on the vulva that would arise and drain over a 24 to 72 hours period, several times per week. Physical examination revealed erythema of the labia minora and introitus with a 4 mm, pink, dome-shaped soft papule on the left labium minus. Wet mount, microbiologic cultures and sexually transmitted infection (STI) screenings were unremarkable. Histopathologic examination revealed a well-circumscribed nodule of suppurative granulomatous inflammation arising in a background of mucosa with Fordyce spots, the majority of which were infiltrated by Demodex spp. Treatment with oral ivermectin and topical metronidazole cream resulted in a symptom-free period of 22 months. This case represents an unusual presentation of symptomatic Demodex infestation.