Mouth Numbness as a Symptom of Multiple Sclerosis

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While many people with MS experience numbness and tingling at some point, you may or may not have heard of or experienced numbness and tingling of the mouth—a particularly unpleasant sensation.

In multiple sclerosis, mouth numbness, like other sensory disturbances, is associated with damage to myelin, the fatty sheath that insulates nerve fibers. It generally occurs from a lesion in the brainstem and may affect the face as well.

Like other MS symptoms, a healthcare provider can diagnose new numbness using an MRI. One study suggests also using trigeminal somatosensory evoked potentials as a diagnostic tool.

Mother with her child, both eating a long strand of spaghetti
Martin Novak / Getty Images

What Does Mouth Numbness Feel Like?

The symptoms of mouth numbness can vary somewhat:

  • Some people describe mouth numbness as being similar to getting a cavity filled (when your gum is anesthetized).
  • Others describe a "swollen" or "burning" sensation on their tongue or elsewhere inside their mouth.

Due to the numbness, some people may begin chewing and holding food on the unaffected (or less affected) side of the mouth. Others may lose their appetite due to the unpleasant experience of eating—it's especially important to talk to your healthcare provider if this is the case. Dental care providers also need to be aware of issues affecting those with MS.

Can Tongue Numbness Be Treated?

There is no specific medication to treat mouth numbness. If it is severe though, your healthcare provider may prescribe you a steroid to ease your symptoms. The good news is that MS-related numbness is generally transient, so it should remit.

One thing to note is that you should be very careful about chewing when you are experiencing numbness in your mouth. Find food that is soft and that does not present a choking hazard if it is not fully chewed, especially if you have difficulty swallowing (another symptom of MS).

In addition, chew slowly so you do not accidentally bite the inside of your mouth, which can be quite painful. You also want to be careful about drinking hot liquids, as they may inadvertently burn your tongue or the inside of your mouth.

Are There Other MS Mouth Symptoms?

Keep in mind that, besides numbness, MS can cause other mouth-related symptoms.

Taste Deficits

Taste disturbances are common in MS, ranging in severity from subtle to more severe. In one study in the Journal of Neurology, investigators administered a taste test to 73 people with MS and 73 matched controls. The test measured sweet (sucrose), sour (citric acid), bitter (caffeine), and salty (salt) taste perception on the top and bottom of the tongue.

Results revealed that the people with MS had significantly lower taste identification scores, compared to the controls (with the biggest deficit being that for salt).

Moreover, a positive correlation was found between the degree of the taste deficit and the number and size of MS lesions in certain parts of the brain (like the frontal and temporal lobes).

Trigeminal Neuralgia

Trigeminal neuralgia is an exquisitely painful condition of the face. In MS, it results from damage to the trigeminal nerve (a nerve in your face that transmits sensory signals to your brain and also helps control some of the muscles involved in chewing).

Episodes of trigeminal neuralgia are short-lived (usually lasting seconds) but severe and debilitating, causing stabbing, electric shock-like attacks of pain, commonly in the jaw, teeth, and gums. It can usually be treated with the anti-seizure medications Tegretol (carbamazepine) or Trileptal (oxcarbazepine).

What Else Can Cause Tongue Numbness?

It's a good idea to get tongue numbness checked out by your healthcare provider because it may not be due to your MS. This symptom can have a number of other potential causes, including:

  • Allergies: Allergic reactions to food and medications can lead to swelling of the tongue, which may impair nerve function.
  • Raynaud's syndrome: This condition primarily limits blood flow to the fingers and toes, but it can also affect the lips and tongue. In rare cases, this may happen as a result of chemotherapy or radiation treatments.
  • Infection: Certain infectious agents, including some herpes viruses, can cause inflammation that may injure or compress nerves around your mouth, leading to numbness in the tongue and other nearby structures.
  • Thalamic stroke: A stroke in the thalamus (a region of the brain) can cause numbness in the tip of the tongue and a portion of the lower lip.
  • Vitamin B12 deficiency: Low levels of this important vitamin can lead to tongue inflammation that may interfere with nerve function.

In some cases, such as stroke and infection, a numb tongue may be an early sign of a serious medical problem. If you have tongue numbness accompanied by difficulty breathing or any severe symptoms, call your healthcare provider or seek immediate medical attention.

A Word From Verywell

If you have MS and are experiencing isolated mouth numbness (or other mouth-related symptoms), you can at least include MS as one of the possible causes. Consider yourself lucky, too, if your neurologist has even heard of this as a symptom of MS, as it appears to be less commonly reported than other symptoms.

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12 Sources
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