Three cases of dermatomyositis are descriptionbed. In one the condition was rapidly fatal. A skin rash was present which was indistinguishable from pemphigus acutus. The condition could readily have been diagnosed as the Stevens-Johnson syndrome in error. In another patient the disease was chronic. The dermatological findings were those of epidermolysis bullosa, and an associated hypertrichosis with pigmentation and muscle weakness made the diagnosis of chronic porphyria seem probable. Porphyrinuria was however not present. The third patient showed some intermediate features. Similar findings in the literature on dermatomyositis are reviewed and discussed.