[Differential diagnosis of red faces].

The term "red face" is reserved for lesions located exclusively or very predominantly on the face. Diagnosis is based on different data: date and mode of appearance, characteristics of the erythema, functional signs, and associated systemic manifestations. A case of red face can have an infectious origin, caused by vascular, congenital, or acquired lesions, or be caused by photodermatosis, or be the main location of inflammatory dermatosis or collagenosis, but depending on the clinical context, many other diagnoses can be suggested. A few observations are presented so as to discuss the management of red face in the atopic patient, the role played by ultraviolet rays in the cutaneous lesions of dermatomyositis, as well as the diagnostic criteria of polymorphous light eruption, and lupus erythematosus.