Aphthous stomatitis the lesions, the healing time of individual ulcers and whether a scar is left after healing (see below). This is the most common type of aphthous stomatitis, accounting for about 80–85% of all cases. This subtype is termed minor aphthous ulceration (MiAU), or minor recurrent aphthous stomatitis (MiRAS). The lesions themselves may be referred to as minor aphthae or minor aphthous ulcers. These lesions are generally less than 10 mm in diameter (usually about 2–3 mm), and affect non-keratinized mucosal surfaces (i.e. the labial and buccal mucosa, lateral borders of the tongue and the floor of the mouth). Usually several
Aphthous stomatitis not a single entity but rather a group of conditions with different causes. Multiple research studies have attempted to identify a causative organism, but aphthous stomatitis appears to be non-contagious, non-infectious, and not sexually transmissible. The mucosal destruction is thought to be the result of a T cell (T lymphocyte) mediated immune response which involves the generation of interleukins and tumor necrosis factor alpha (TNF-α). Mast cells and macrophages are also involved, secreting TNF-α along with the T cells. When early aphthous ulcers are biopsied, the histologic appearance shows a dense inflammatory infiltrate, 80% of which is made up of