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Canker Sores

Aphthous ulcers ("canker sores") are the most common oral irritation of young adults.


Aphthous ulcers ("canker sores") are the most common oral irritation of young adults. An aphthous ulcer is a shallow erosion with a yellow-white center surrounded by a narrow, red ring. They are most often oval-shaped, with a diameter of 1/8 to 1/4 inch. Aphthous ulcers have no blisters. They occur on the soft surfaces of the mouth such as the inner cheeks, inner lips, soft areas of the roof and floor of the mouth, tongue, gums, and pharynx (throat). There may be one or several aphthous ulcers present.

Twenty to sixty percent of the population have had aphthous ulcers at some time in their lives. People most frequently get them between the ages of 10 and 40 and they are often recurrent. Tingling or burning may precede the lesions by 24 hours. The main "problem" caused by aphthous ulcers is pain, which varies considerably among patients from slight to severe. The acute painful phase lasts 3 to 4 days with complete healing in 7 to 10 days. Aphthous ulcers heal without scaring.


No specific cause of aphthous ulcers has been identified. Mouth trauma, local immune response, hormonal changes, certain foods, allergies, vitamin deficiencies, physical and emotional stress, are possible contributing factors.

Aphthous ulcers are not cancerous or contagious. They are not the same as "cold sores" which are caused by Herpes Simplex Virus.


Since the cause for aphthous ulcers has not specifically been identified, no cure has been found. Therapy is aimed at controlling pain. Avoid salty, spicy, and citrus foods, as these may cause increased pain.

Treatment with ibuprofen or acetaminophen may help reduce the pain. Applying ice to the ulcers or covering them with a protectant called orabase can help control the pain of aphthous ulcers.

Occasionally it may be necessary to seek medical treatment with topical anesthetics to reduce the pain or an antibiotic solution to prevent secondary infection.

If ulcers persist longer than 10 days or are unusually large (1/2 inch or larger), they should be evaluated by a medical professional.