Aphthous stomatitis 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. "Aphthous affectations" and "aphthous ulcerations" of the mouth are mentioned several times in the treatise "Of the Epidemics" (part of the Hippocratic corpus, in the 4th
Aphthous stomatitis scarring. The ulceration may affect keratinized mucosal surfaces in addition to non keratinized. Herpetiform ulceration is often extremely painful, and the lesions recur more frequently than minor or major aphthous ulcers. Recurrence may be so frequent that ulceration is virtually continuous. It generally occurs in a slightly older age group than the other subtypes, and females are affected slightly more frequently than males. Recurrent oral ulceration associated with systemic conditions is termed "RAS type ulceration", "RAS like ulceration", or "aphthous-like ulcers". Aphthous stomatitis occurs in individuals with no associated systemic disease. Persons with certain systemic diseases may be prone to