Idiopathic plantar hidradenitis.

We describe four cases of idiopathic plantar hidradenitis (IPH), a form of neutrophilic eccrine hidradenitis (NEH) localized on the feet of otherwise healthy young persons. Our patients were all males, 8-17 years old, in apparently good health, but presenting erythematous painful papules, plaques and nodules on the soles. They were afebrile and there were no constitutional symptoms. The differential diagnoses included erythema nodosum, vasculitis and traumatic plantar urticaria. The histological features of IPH are similar to those of NEH, except for the absence of syringosquamous metaplasia. The patients were treated with topical steroids and oral NSAID, with total resolution of the lesions in 1 or 2 weeks.