Prurigo in dermatomyositis.

on his lower back and upper extremities. Each eruption was a bean-sized solitary papule ( fig. 1 a). Many of the papules had erosions or crusts due to excoriation. Some papules were arranged linearly or clustered to form small plaques. Steroid ointment was ineffective. He also had other cutaneous manifestations of dermatomyositis such as heliotrope rash, flagellate erythema of the upper back, periungual erythema and mechanic’s hands. Histologically, in the biopsy specimen of a papule of the lower trunk, there was a dermal cellular infiltrate comprising lymphocytes and histiocytes around superficial vessels with a weak irregular acanthosis ( fig. 1 b). Faint deposition of mucin was detected beneath the epidermis as assessed by Alcian blue staining. Laboratory findings revealed elevated levels of serum creatine kinase, 1,022 U/ml (normal 35–175). Pruritic eruptions were dramatically improved after the increase in doses of oral prednisolone. An intense survey revealed no internal malignancy, while an interstitial pneumonia which seemed to be caused by dermatomyositis was detected. Case 2. An 80-year-old man had been diagnosed as having dermatomyositis with proximal myopathy, poikiloderma and a high value of creatine kinase (5,191 U/ml) 1 year before the consultation at our clinic. Systemic corticosteroid (prednisolone 60 mg/day) was successful to relieve these symptoms. After oral prednisolone had been reduced to a dose as low as 4 mg/day, pruritic eruptions appeared on his back. Eruptions were bean-sized to fingertip-sized elevated urticarial papules, which were distributed solitarily around his waist. Some of the papules were clustered to form elevated plaques ( fig. 2 ). Eruptions were successfully treated with topical corticosteroid. No malignancy was found during our observation.