Hidradenitis suppurativa complicating naevus comedonicus: the possible influence of mechanical stress on the development of hidradenitis suppurativa.

Naevus comedonicus is a rare, benign hamartoma consisting of grouped abnormal hair follicles and, occasionally, associated with other diseases. We describe an infant who developed hidradenitis-like lesions in an inguinal naevus comedonicus following increased mechanical stress on the region. It is speculated that the degree of strain on a hair follicle is increased when its diameter is increased, leading to wall ruptures. We hypothesise that this serendipitous observation provides a model for the way mechanical stress can account for the development of hidradenitis suppurativa in some patients.