A peculiar form of amicrobial pustulosis of the folds associated with systemic lupus erythematosus and other auto-immune diseases.

Amicrobial pustulosis of the folds is a new entity which was initially described in association with systemic lupus erythematosus (SLE). We report four cases of this rare pustulosis occurring in the course of various auto-immune disorders. Dermatological features were similar in all patients. The primary lesions were small pustules which coalesced and formed erosive areas underlined with pustular lesions. They were localized in the folds. Three of the four patients had also isolated pustules on the scalp. Spongiform pustules were histologically present. A primary bacterial or fungal infection was ruled out by cultures on appropriate media. Serum calcium level was normal. Associated auto-immune diseases were: systemic lupus erythematosus, incomplete systemic lupus erythematosus, 'idiopathic' thrombocytopenic purpura and myasthenia gravis without thymoma (one of each). The relationship between this peculiar form of pustulosis and autoimmunity remains to be elucidated. The pustulosis did not respond to antibiotics but disappeared with systemic or topical corticosteroids.