Apthouse Ulcer, also known as “canker sore or ulcer” is a condition which is signified by the presence of small ulcers on the soft tissues of oral cavity (Greek aptha=mouth ulcer). It is a noncontagious and benign condition of non-keratinizing surfaces in the mouth of otherwise healthy persons. It affects almost 20 % of population to a greater or lesser degree.  Local itching, burning, stinging and pain are usually felt a few hours before the appearance of the lesions, which is accompanied by severe pain. The pain tends to subside gradually, and later disappears completely. The apthae (plural of aptha, the ulcer) tend to return after some period.

The cause of this ulcer is not clearly understood. No causing organism has been found. It is not contagious or infection. It is considered by some to occur as a result of T cell related response of the autoimmune system. However, no association exists with other autoimmune diseases which all tend to occur together and behave similarly.  Nearly 40% of patients have a family history. A high rate of occurrence has been reported during exam days which lowers during vacations. An association has been noted with certain systemic diseases, especially intestinal and stomach diseases. It is possible that it occurrence of the apthous ulcer is associated with periods of stress and low vitality. Also, a thicker mucosal layer will tend to reduce incidence of the apthous ulcer. Apthous ulcers are also quite common in women during menstruation or pregnancy.

Diagnosis is made on the basis of appearance (red macules), a history of self-healing, and regular repetition. Classification may be made as simple versus complex ulceration, or as minor, major or herpetiform ulceration. Herpetiform Apthous ulceration is not herpetic, but resembles it in appearance. There is no real treatment because a definitive cause is usually identifiable. As such treatment will be for either placebo purpose, to relieve pain, or to prevent secondary infection. Surgical excision is not favored.

The Apthous ulcer is not contagious or infectious, and cannot lead to any other disease except a possible secondary infection. However, in extreme cases when food intake becomes difficult for a long time it may cause debility and weight loss. Apthous stomatitis occurs worldwide, but, surprisingly, is more common in the developed nations.