Aphthous Ulcers / Canker Sores - Pathophysiology, Triggers, Types & Treatment

Aphthous ulcers also called recurrent aphthous stomatitis (RAS) or simply known as canker sore is a common ulcerative inflammatory condition of the oral cavity. The reported prevalence in the general population varies between 5% to 66%. It typically starts in childhood or adolescence as small recurrent, painful, round, or ovoid ulcers with well-defined erythematous margins, and a central yellow or gray floor. The lesions have a recurrent nature meaning that they are episodic once they appear for the first time in an individual’s mouth. The exact cause or etiopathogenesis for aphthous ulcers (canker sores) is unknown, however, it’s thought that ulceration might result from a sudden activation of the cell-mediated immune system at the site of ulceration leading to the liberation of cell signaling molecules or cytokines like TNF-alpha and some other interleukins. These cytokines cause antigen expression on oral epithelial cells. The oral epithelial cells are then recognized by T lymphocytes which then tri