Aphthous stomatitis century BC), although it seems likely that this was oral ulceration as a manifestation of some infectious disease, since they are described as occurring in epidemic-like patterns, with concurrent symptoms such as fever. Aphthous stomatitis was once thought to be a form of recurrent herpes simplex virus infection, and some clinicians still refer to the condition as "herpes" despite this cause having been disproven. The informal term "canker sore" is sometimes used, mainly in North America, either to describe this condition generally, or to refer to the individual ulcers of this condition, or mouth ulcers of any cause unrelated to
Aphthous stomatitis ulcers appear at the same time, but single ulcers are possible. Healing usually takes seven to ten days and leaves no scar. Between episodes of ulceration, there is usually an ulcer-free period of variable length. This subtype makes up about 10% of all cases of aphthous stomatitis. It is termed major aphthous ulceration (MaAU) or major recurrent aphthous stomatitis (MaRAS). Major aphthous ulcers (major aphthae) are similar to minor aphthous ulcers, but are more than 10 mm in diameter and the ulceration is deeper. Because the lesions are larger, healing takes longer (about twenty to thirty days), and may leave