Stomatitis washes away antigens and acts as a barrier. The oral mucosa is also more vascular (has a better blood supply) than skin, meaning that any antigens are more quickly removed from the area by the circulation. Finally, there is substantially less keratin in oral mucosa, meaning that there is less likelihood that haptens will form. Allergic contact stomatitis appears as non-specific inflammation, so it may be mistaken for chronic physical irritation. There may be burning or soreness of the mouth and ulceration. Chronic exposure to the allergen may result in a lichenoid lesion. Plasma cell gingivitis may also occur, which
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