While the precise mechanism by which canker sores are formed has not been definitively determined, various factors which seem to trigger outbreaks of these ulcers have been. Many persons who suffer from canker sores recall some sort of trauma preceding their ulcer development. This trauma might take the form of a minor self-inflicted bite or possibly trauma from some type of food such as a crisp chip. People often notice that the timing of their canker sores coincides with periods of stress. Some women seem to find a relationship between the presence of canker sores and certain phases of their menstrual period.
Most women notice an improvement or remission of canker sores during pregnancy.
Many factors related to diet have been suggested as being instrumental in causing canker sores. Some researchers have felt they have identified a genetic predisposition for canker sores, meaning that parents who suffer from canker sores tend to have children who suffer from these mouth ulcers also. The fact that certain bacterial organisms have been isolated from canker sores suggest that they possibly might be causative in the formation of these ulcers. Immunologic abnormalities and medical conditions. The presence of canker sores may be related to an underlying medical condition.