Aphthous stomatitis affects between 5% and 66% of people, with about 20% of individuals in most populations having the condition to some degree. This makes it the most common<unk>  of the oral mucosa. Aphthous stomatitis occurs worldwide, but is more common in developed countries. Within nations, it is more common in higher socioeconomic groups. Males and females are affected in an equal ratio, and the peak age of onset between 10 and 19 years. About 80% of people with aphthous stomatitis first developed the condition before the age of 30. There have been reports of ethnic variation. For example, in the United States, aphthous stomatitis may be three times more common in white-skinned people than black-skinned people.
symptom of Behçet's disease
symptom of Chilaiditi syndrome
symptom of Rheumatic fever
symptom of Syphilis
symptom of Buruli ulcer
symptom of Herpes labialis
symptom of Stevens–Johnson syndrome
symptom of Leishmaniasis