Recurrent Aphthous Stomatitis (RAS), also known as canker sores, is a common condition characterized by recurring painful ulcers or sores that develop on the mucous membranes inside the mouth. These ulcers typically present as round or oval lesions with a white or yellow center and a red border. The exact cause of RAS is not fully understood, but factors such as stress, hormonal changes, certain foods, and minor mouth injuries are believed to contribute to its development.

RAS can be classified into three main types: minor, major, and herpetiform. Minor aphthous ulcers are the most common and usually heal within one to two weeks without scarring. Major aphthous ulcers are larger and deeper, often taking several weeks to heal and may leave scars. Herpetiform aphthous ulcers are small, numerous ulcers that often merge together, resembling herpes lesions, but are unrelated to the herpes virus.

Treatment for RAS focuses on alleviating pain and promoting healing. This may include topical medications such as corticosteroids or oral rinses containing analgesics or antimicrobial agents. In severe cases, systemic medications or corticosteroid injections may be prescribed.

Although RAS is not contagious or life-threatening, it can significantly affect quality of life due to pain and discomfort. Proper oral hygiene, stress management, and avoiding triggers can help reduce the frequency and severity of RAS outbreaks.