Aphthous Stomatitis
Causes
The exact reason why an aphthous ulcer develops is not known. Approximately 40% of people who get aphthous ulcers have a family history of aphthous ulcer. Current thinking is that the immune system is disturbed by some external factor and reacts abnormally against a protein in mucosal tissue.
Major aphthous ulceration of the palate
According to Dermnet NZ, factors that seem to trigger outbreaks of ulcers include:
- Emotional stress and lack of sleep
- Mechanical trauma, for example, self-inflicted bite
- Nutritional deficiency, particularly of vitamin B, iron, and folic acid
- Certain foods, including chocolate
- Certain toothpastes; this may relate to sodium laureth sulfate (the foaming component of toothpaste)
- Menstruation
- Certain medications, including nicorandil, given for angina
- Viral infections.
Cellular mechanisms
The cause is believed to be multifactorial. It has been suggested that aphthous stomatitis is 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.
Associations
Minor aphthous ulceration of the lip
Aphthous stomatitis has been associated with other autoimmune diseases, namely systemic lupus erythematosus and inflammatory bowel diseases. However, common autoantibodies are not detected in most patients, and the condition tends to resolve spontaneously with advancing age rather than worsen.
Evidence for the T cell-mediated mechanism of mucosal destruction is strong, but the exact triggers for this process are 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.