What is burning mouth syndrome?

The U.S. National Institute of Dental and Craniofacial Research (NIDCR) describes burning mouth syndrome (BMS) as a burning, scalding or tingling feeling that recurs for months or longer, often every day. It most often affects the tongue, but can involve the lips, the roof of the mouth or the whole mouth. Some people also notice:

• A dry mouth feeling
• Altered taste, such as a metallic taste
• Numbness that comes and goes
• Relief while eating or drinking, with pain returning afterward

DermNet describes three daily patterns: pain that is absent on waking and builds through the day, pain that is present day and night, and pain that comes and goes with some pain-free days. It rarely wakes people from sleep.

DermNet estimates BMS affects about 1% of the general population, with much higher rates in some groups such as postmenopausal women. It is rarely seen before age 30.

The exact cause is not known. NIDCR explains that experts believe it results from damage to the nerves that control pain and taste. A review in PMC defines it as a chronic pain condition with burning in a mouth lining that looks clinically healthy. NIDCR lists anxiety, depression and stress among factors linked to burning in the mouth.

A burning tongue is a symptom with many possible sources. BMS is the label used only when none of them is found. NIDCR and DermNet list conditions a dentist or doctor will check for:

• Dry mouth from medicines, Sjögren's disease or radiation treatment
• Oral thrush and other mouth infections
• Low iron, vitamin B12, folate or zinc
• Diabetes and thyroid problems
• Acid reflux
• Allergy or sensitivity to toothpaste, dental materials or foods
• Oral lichen planus, ulcers and other visible mouth conditions
• Certain medicines, including some blood pressure drugs
• Habits such as tongue thrusting or rubbing the tongue on the teeth

If one of these is found and treated, the burning often improves, and the diagnosis is a secondary burning mouth rather than BMS.

There is no single test. Diagnosis can take time because the mouth usually looks normal. Expect a medical history, mouth examination and, depending on your symptoms, some of these: blood tests for blood sugar, thyroid function and nutrient levels; an oral swab for yeast; allergy or patch testing; and saliva flow measurement. Your dentist may refer you to an oral medicine specialist. In true BMS these tests come back normal.

There is no cure, and treatment is individual; many people try more than one approach. Options a specialist may discuss include:

A systematic review in PMC concluded that CBT, topical capsaicin, clonazepam and laser therapy showed favorable outcomes but that larger, better-controlled trials are needed. DermNet notes about half to two-thirds of people improve to some degree over several years, although spontaneous complete recovery is uncommon.

• Sip cold water, suck ice chips or chew sugar-free gum for short-term relief, as NIDCR suggests.
• Avoid tobacco, alcohol, alcohol-based mouthwash, hot or spicy food and acidic foods such as citrus.
• Try a mild, unflavored toothpaste without sodium lauryl sulfate or strong mint or cinnamon flavors.
• Manage stress, as symptoms often flare with it.
• Do not stop a medicine you suspect without talking to the prescriber.

Cleaning or scraping the tongue does not treat BMS, and harsh scrubbing of an already sensitive tongue is best avoided.