This report describes a patient, whom we observed for 3 years, exhibiting a coincidence of dermatitis herpetiformis Duhring and systemic Lupus erythematosus. The difficulties involved in demarcating bullous lupus erythematosus from the more rare association of bullous pemphigoid or dermatitis herpetiformis with systemic lupus erythematosus are discussed in connection with differential, histological, direct and indirect immunofluorescence diagnostic aids.