A Rare Case of Coexistent Hidradenitis Suppurativa, Steatocystoma Multiplex with Dorsal Aquagenic Keratoderma: The Elephant in the Room Regarding a ‘Follicular Occlusion Pentad’

Abstract

Steatocystoma multiplex is characterised by skin-coloured papules and nodules over various parts of body. Hidradenitis suppurativa is a chronic inflammatory disorder characterised by nodules, discharging sinuses and scarring. Aquagenic keratoderma is characterised by thickened skin of palms and soles with white translucent papules which increases on water exposure. A 28-year-old male presented with progressively increasing asymptomatic yellowish papules and nodules without punctum or discharge over his face for 10 years. He also developed recurrent painful nodules with discharging sinuses and puckering of skin over bilateral axillae, groin, trunk, and buttocks for the last 2 years, with thickening of skin over the dorsal aspect of bilateral hands and feet for 1 year, which got accentuated on water exposure. Skin biopsies were done from lesions over the face, axillae, and hands, and histopathology findings were consistent with steatocystoma, hidradenitis suppurativa, and keratoderma, respectively. The patient was started on oral isotretinoin 0.5 mg/kg daily, topical clindamycin twice daily over axillae and urea-based emollient twice daily over hands and feet. There was complete resolution in nodules and sinuses and mild improvement in steatocystoma and keratoderma lesions after 6 months. We present this case due to the rarity of coexistence of the three conditions in a single patient, the unusual location of steatocystoma and aquagenic keratoderma, and possibly a new impending follicular occlusion pentad considering the addition of steatocystoma to the existing tetrad.