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Mouth sores

Various types of sores can appear anywhere within the mouth, including the inner cheeks, gums, tongue, lips, or palate.

Causes

Most mouth sores are cold sores (also called fever blisters), canker sores, or other irritation caused by:

Cold sores are caused by herpes simplex virus and are very contagious. Usually, you have tenderness, tingling, or burning before the actual sore appears. Herpes sores usually begin as blisters and then crust over.

The herpes virus can reside in your body for years, appearing as a mouth sore only when something provokes it. Such circumstances may include another illness, especially if there is a fever, stress, hormonal changes (such as menstruation), and sun exposure.

Canker sores are NOT contagious and can appear as a single pale or yellow ulcer with a red outer ring, or as a cluster of such lesions. The cause of canker sores is not entirely clear, but may be related to:

For unknown reasons, women seem to get canker sores more often than men. This may be related to hormonal changes.

Less commonly, mouth sores can be a sign of an underlying illness, tumor, or reaction to a medication. Such potential illnesses can be grouped into several broad categories:

Drugs that may cause mouth sores include chemotherapeutic agents for cancer, aspirin, barbiturates (used for insomnia), gold (used for rheumatoid arthritis), penicillin, phenytoin (used for seizures), streptomycin, or sulfonamides.

Home Care

Mouth sores generally last 10 to 14 days, even if you don't do anything. They sometimes last up to 6 weeks. The following steps can make you feel better:

For canker sores:

Nonprescription preparations, like Orabase, can protect a sore inside the lip and on the gums. Blistex or Campho-Phenique may provide some relief of canker sores and fever blisters, especially if applied when the sore initially appears.

Additional steps that may help cold sores or fever blisters:

Antiviral medications for herpes lesions of the mouth may be recommended by your doctor. Some experts feel that they shorten the time that the blisters are present, while others claim that these drugs make no difference.

When to Contact a Medical Professional

Call your doctor if:

What to Expect at Your Office Visit

Your doctor will perform a physical examination, focusing on your mouth and tongue. Medical history questions may include the following:

Treatment may depend on the underlying cause of the mouth sore.

A topical anesthetic (applied to a localized area of the skin) such as lidocaine or xylocaine may be used to relieve pain (but should be avoided in children).

An antifungal medication may be prescribed for oral thrush (a yeast infection).

An antiviral medication may be prescribed for herpes lesions (although, some feel that this does not shorten the length of time that the lesions are present)

Anti-inflammatory medications may be prescribed for severe or persistent canker sores.

Prevention

You can reduce your chance of getting common mouth sores by:

You can avoid mechanical irritation by:

If you seem to get canker sores often, talk to your doctor about taking folate and vitamin B12 to prevent outbreaks.

If you get cold sores often, taking L-lysine tablets or increasing lysine in your diet (found in fish, chicken, eggs, and potatoes) may reduce outbreaks. Do NOT use L-lysine if you have high cholesterol, heart disease, or high triglycerides.

To prevent the spread of herpes sores, do not kiss or have oral sex with someone with a cold sore or fever blister. Do not participate in these activities when you have an active cold sore. Do not share razors, lip balm, toothbrushes, or lipsticks.

To prevent cancerous mouth lesions:

Alternative Names

Aphthous stomatitis

References

Daniels TE. Diseases of the mouth and salivary glands. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 451.

Update Date: 11/15/2009

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.


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