Aphthous stomatitis scars. Each episode of ulceration usually produces a greater number of ulcers, and the time between attacks is less than seen in minor aphthous stomatitis. Major aphthous ulceration usually affects non keratinized mucosal surfaces, but less commonly keratinized mucosa may also be involved, such as the dorsum (top surface) of the tongue or the gingiva (gums). The soft palate or the fauces (back of the throat) may also be involved, the latter being part of the oropharynx rather than the oral cavity. Compared to minor aphthous ulceration, major aphthae tend to have an irregular outline. Herpetiform ulcers, (also termed stomatitis
Aphthous stomatitis unknown and are thought to be multiple and varied from one person to the next. This suggests that there are a number of possible triggers, each of which is capable of producing the disease in different subgroups. In other words, different subgroups appear to have different causes for the condition. These can be considered in three general groups, namely primary immuno-dysregulation, decrease of the mucosal barrier and states of heightened antigenic sensitivity (see below). Risk factors in aphthous stomatitis are also sometimes considered as either host-related or environmental. At least 40% of people with aphthous stomatitis have a positive family