Aphthous Stomatitis
Immunology

At least 40% of people with aphthous stomatitis have a positive family history, suggesting that some people are genetically predisposed to suffering with oral ulceration.

Minor aphthous ulceration of the buccal mucosa

There are many gene variations (called HLA types) associated with aphthous stomatitis. However, these HLA types are inconsistently associated with the condition, and also vary according to ethnicity. People who have a positive family history of aphthous stomatitis tend to develop a more severe form of the condition, and at an earlier age than is typical.

Stress has effects on the immune system, which may explain why some cases directly correlate with stress. It is often stated that in studies of sufferers who are students, ulceration is exacerbated during examination periods and lessened during periods of vacation.

Alternatively, it has been suggested that oral parafunctional activities such as lip or cheek chewing become more pronounced during periods of stress, and hence the mucosa is subjected to more minor trauma.

Aphthous-like ulceration also occurs in conditions involving weakened immune systems, e.g. cyclic neutropenia and human immunodeficiency virus infection.