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 oral ulceration, but this is secondary to the underlying medical condition (see the systemic disease section). This kind of ulceration is considered by some to be separate from true aphthous stomatitis. However, this definition is not strictly applied. For example, many sources refer to oral ulceration caused by anemia and/or nutritional deficiencies as aphthous stomatitis, and some also consider Behçet's disease to be a variant. The vast majority of people with aphthous stomatitis have minor symptoms and do not require any specific therapy. The pain is often tolerable with simple dietary modification during an episode of ulceration such as avoiding