Mouth ulcers are sores or open lesions in the mouth.

See also: Canker sores

Oral ulcer; Stomatitis - ulcerative; Ulcer - mouth

Mouth ulcers are caused by many disorders. These include:

• Canker sores
• Gingivostomatitis
• Herpes simplex (fever blister)
• Leukoplakia
• Oral cancer
• Oral lichen planus
• Oral thrush

The skin lesion of histoplasmosis may also appear as a mouth ulcer.

Symptoms vary and depend on the specific cause of the mouth ulcer. In general, symptoms may include:

• Open sores in the mouth
• Pain or discomfort in the mouth

A health care provider or dentist usually diagnoses the type of mouth ulcer, based on its appearance and location. Blood tests or a biopsy of the ulcer may be needed to confirm the cause.

The goal of treatment is to relieve symptoms. The cause, if known, should be treated.

Gentle, thorough oral hygiene may relieve some of the symptoms. Topical (rubbed on) antihistamines, antacids, corticosteroids, or other soothing preparations may be recommended for applying directly to the ulcer.

Avoid hot or spicy foods, which often increase the pain of mouth ulcers.

The outcome varies depending on the cause of the ulcer. Many mouth ulcers are harmless and heal without treatment.

There are types of cancer, however, that may first appear as a mouth ulcer that does not heal. See: Squamous cell carcinoma

• Cellulitis of the mouth, from secondary bacterial infection of ulcers
• Dental infections (tooth abscesses)
• Oral cancer
• Spread of contagious disorders to other people

Call for an appointment with your health care provider if your mouth ulcers don't go away after 3 weeks. Call for an appointment with your health care provider if mouth ulcers return frequently, or if new symptoms develop.

Good oral hygiene may help prevent some types of mouth ulcers, as well as some complications from mouth ulcers. Good oral hygiene includes brushing the teeth at least twice per day, flossing at least daily, and getting regular professional dental cleanings and examinations.

Muñoz-Corcuera M, Esparza-Gómez G, González-Moles MA, Bascones-Martínez A. Oral ulcers: clinical aspects. A tool for dermatologists. Part I. Acute ulcers. Clin Exp Dermatol. 2009 Apr;34(3):289-94.

Muñoz-Corcuera M, Esparza-Gómez G, González-Moles MA, Bascones-Martínez A. Oral ulcers: clinical aspects. A tool for dermatologists. Part II. Chronic ulcers. Clin Exp Dermatol. 2009 Jun;34(4):456-61. Epub 2009 Apr 14.

Mirowski GW, Mark LA. Oral disease and oral-cutaneous manifestations of gastrointestinal and liver disease. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran’s Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 22.