[Recurrent oral ulcer: clinical characteristic and differential diagnosis].

Recurrent aphthous stomatitis (RAS), are common inflammatory lesions of the oral mucous, usually round or ovoid, circumscribed by erythematous haloes with a yellow-grey floor and mostly painful. The RAS has reached an incidence about 20% in general population, present on any aged group, especially adolescents and young adults. Etiopathogenesis of RAS is not entirely understood. Some factors involved include immune system anomalies, infections, nutritional deficiency, mucous traumatism, food or contact allergy, autoimmunity illness and cancer; together with psychiatric, genetic and environment agents. In this article, main clinical features, etiology related factors, differential diagnosis and initial study of patients consulting for RAS are presented.