Plantar hidradenitis in children induced by exposure to wet footwear.

Painful erythematous papules and nodules involving either the palms of the hands, or, more commonly, the soles of the feet, characterize palmoplantar eccrine hidradenitis or palmoplantar hidradenitis (PH). The younger pediatric population is predominately affected. Histologically, the eccrine gland apparatus is the target of inflammatory neutrophilic infiltrates. This entity has been reported under a variety of names, including traumatic plantar urticaria, neutrophilic eccrine hidradenitis, plantar erythema nodosum, and idiopathic recurrent palmoplantar hidradenitis. All are essentially the same process, described in different forms. Despite the growing number of reported cases, the pathogenesis remains obscure. We present four children with PH of the soles of the feet, who shared a common recent history of exposure to cold, damp, footwear. The temporal relationship between exposure to dampness and cold and the appearance of the skin lesions suggest a possible pathogenetic mechanism.