Canker sores are ulcers

Canker sores are ulcers of about 1 to 2 mm in diameter that develop on the oral mucous membranes (mouth, tongue, lips, gums). Each ulcer form a small crater surrounded by a yellowish red halo. It is estimated that 17% of the population is affected repeatedly. Canker sores can occur in isolation, in groups of two or three, but sometimes in larger group. Ulcers have a tendency to disperse on the mouth rather than forming clusters as in the case of ulcers associated with herpes. Canker sores are painful but they do not pose a threat to health. They are neither infectious nor contagious. A full recovery may take two to three weeks, but the painful period lasts only two to five days. Relapses are frequent. Note. Canker sores may also be one of the first symptoms of Behest’s disease (or large aphtose) a much more serious trouble, but more rare.