Systemic lupus erythematosus presenting with oral mucosal lesions: easily missed?

Two caucasian patients are described in whom oral mucosal lesions were the first manifestation of systemic lupus erythematosus. In both cases the diagnosis was delayed despite histological examination of oral lesions. Treatment with antimalarials and azathioprine was of significant benefit. In the absence of cutaneous or systemic features, distinguishing oral lupus erythematosus from lichen planus and epidermal dysplasia can be difficult, both clinically and on histology, and requires a high index of suspicion.