Canker sores, also known as aphthous ulcers, are small, shallow, painful lesions that develop on the soft tissues inside the mouth. They typically appear on the inner cheeks, lips, under or on the tongue, at the base of the gums, or on the soft palate. These sores usually have a white or yellow center with a red border and can make eating and talking uncomfortable
. Canker sores are not contagious and differ from cold sores, which occur outside the mouth around the lips and are caused by the herpes virus. Canker sores only occur inside the mouth
. There are three main types of canker sores:
- Minor canker sores: The most common type, small and oval-shaped, healing without scarring within one to two weeks.
- Major canker sores: Larger and deeper, more painful, may take up to six weeks to heal and can leave scars.
- Herpetiform canker sores: Uncommon, appearing as clusters of tiny sores that may merge into larger ulcers, healing without scarring in one to two weeks. Despite the name, they are not caused by the herpes virus
The exact cause of canker sores is unclear, but they are believed to result from a combination of factors such as minor mouth injuries, stress, hormonal changes, food sensitivities (e.g., to chocolate, coffee, nuts, acidic foods), nutritional deficiencies (vitamin B-12, zinc, folate, iron), allergic responses to mouth bacteria, and certain medical conditions like celiac disease or inflammatory bowel diseases
. Most canker sores heal on their own within one to two weeks, but larger or persistent sores may require medical attention. Symptoms often start with a tingling or burning sensation before the sore appears, followed by pain that worsens with irritating foods or mouth movements
. In summary, canker sores are common, benign, non-contagious mouth ulcers that cause discomfort but typically resolve without treatment within a couple of weeks
