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 cause debilitating chronic pain and interfere with comfortable eating. In severe cases, this prevents adequate nutrient intake leading to malnutrition and weight loss. Aphthous ulcers typically begin as erythematous macules (reddened, flat area of mucosa) which develop into ulcers that are covered with a yellow-grey fibrinous membrane that can be scraped away. A reddish "halo" surrounds the ulcer. The size, number, location, healing time, and periodicity between episodes of ulcer formation are all dependent upon the subtype of aphthous stomatitis. The cause is not entirely clear, but is thought to be multifactorial. It has been suggested that aphthous stomatitis is