Four patients with systemic lupus erythematosus (SLE) had a vesicobullous eruption that histologically resembled dermatitis herpetiformis. Immunofluorescence microscopy patterns in the skin studied in three patients, however, were characteristic of SLE. Treatment of the underlying collagen-vascular disease improved the eruption, while recurrence coincided with exacerbation of the systemic disease. This distinctive lesion is an important parameter of SLE activity.