Steatocystoma multiplex suppurativa associated with hidradenitis suppurativa successfully treated with adalimumab

Steatocystoma multiplex (SM) is a rare autosomal dominant disease characterized by multiple asymptomatic intradermal true sebaceous cysts of variable size. These lesions may occasionally rupture, become inflamed, painful and heal with scarring [SM suppurativa (SMS)], thus sharing overlapping features with hidradenitis suppurativa (HS). The question of whether SMS simply mimics HS or if the two diseases may be associated remains open. We report three patients (2 M/1 F; age: 47, 27 and 40 years) affected by SMS showing inflammatory lesions on the areas typically affected by HS. Repeated skin biopsy from each patient showed true sebaceous cysts in some specimens and findings compatible with HS, without sebaceous glands evidence in others, supporting coexistence of the two diseases. Adalimumab at the initial dose of 160 mg (day 1), followed by 80 mg (day 15), and maintained at the dose of 40 mg every week from day 29 on, improved both HS and SMS lesions, including also non‐inflammatory cystic lesions.