Dermatomyositis with a pityriasis rubra pilaris-like eruption: a little-known distinctive cutaneous manifestation of dermatomyositis.

A pityriasis rubra pilaris-like eruption has been described in patients with dermatomyositis. These patients showed generalized follicular hyperkeratosis and diffuse thickening of the palms and soles. Histopathological findings consisted of keratotic plugging of the follicular infundibulum and features of erector pili myositis. We report on an 18-year-old woman with dermatomyositis. The diagnosis was established by characteristic enzymatic alterations, electromyographic pattern of myositis and the findings in a muscle biopsy, although the patient had no evidence of muscular weakness during a follow-up of 14 years. She developed an erythematosus and squamous eruption associated with diffuse palmoplantar keratoderma. Histopathological features consisted of a papillomatous epidermis with spicules of compact eosinophilic hyperkeratosis over the tips of papillae that were not related to hair follicles. Pityriasis rubra pilaris-like eruption seems to be a characteristic although uncommon cutaneous manifestation in dermatomyositis.