Stomatitis IV (delayed) hypersensitivity reaction that occurs in susceptible atopic individuals when allergens penetrate the skin or mucosa. Allergens, which may be different for different individuals, combine with epithelial-derived proteins, forming haptens which bind with Langerhans cells in the mucosa, which in turn present the antigen on their surface to T lymphocytes, sensitizing them to that antigen and causing them to produce many specific clones. The second time that specific antigen is encountered, an inflammatory reaction is triggered at the site of exposure. Allergic contact stomatitis is less common than allergic contact dermatitis because the mouth is coated in saliva, 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