Scalp involvement in dermatomyositis. Often overlooked or misdiagnosed.

OBJECTIVE: To characterize scalp involvement in patients with dermatomyositis.

DESIGN: Case series.

PATIENTS: All patients with dermatomyositis seen in our office between 1988 and mid 1993. Patient inclusion in this study required fulfillment of three or more of Bohan and Peter's criteria for dermatomyositis.

RESULTS: Of 17 patients with the diagnosis of dermatomyositis, scalp involvement was present in 14. Five of the 14 patients with scalp involvement were diagnosed as having scalp psoriasis or seborrheic dermatitis before progression of their disease or tissue examination revealed the diagnosis of dermatomyositis. In all patients, the scalp involvement was manifested as atrophic, erythematous, scaly plaques. In addition, alopecia was noted in six of the 14 patients. Treatment of cutaneous involvement included sun avoidance, topical corticosteroids and/or antimalarials, and/or methotrexate.

CONCLUSIONS: Recognition of this process is important because scalp involvement is often overlooked, may be misdiagnosed initially, and can be the presenting complaint in some patients with dermatomyositis.