What is burning mouth syndrome?
Burning mouth syndrome (BMS) is a condition in which someone experiences a burning or abnormal sensation within the mouth without any visible cause.
There are no official diagnostic criteria, but some journals describe it as occurring for 2+ hours per day for at least 3 months (1).
Burning mouth syndrome is also sometimes called by the following names:
- Oral dysesthesia
Other causes of mouth pain, such as oral thrush, Sjogren’s syndrome, geographic tongue, xerostomia, acid reflux, diabetes, smoking, reactions to dentures, allergy to mercury fillings, nutrient deficiencies (B vitamins and zinc), or medication side effects (ACE inhibitors) should be ruled out (2, 3, 4, 5, 41, 42, 43).
What are the symptoms of burning mouth syndrome?
Symptoms commonly occur on both sides of the mouth and in the front two-thirds of the tongue. They can include the following (6, 7):
- Altered taste sensation
What are the proposed causes/contributing factors?
The following are some proposed causes or contributing factors of burning mouth syndrome:
Although the etiology remains unknown, some research has discovered that people with burning mouth syndrome tend to have higher salivary and systemic levels of pro-inflammatory cytokines and proteins like cystatin SN that are released in response to inflammation (1, 8).
It is proposed that some of these cytokines may make pain receptors more sensitive, triggering the pain and burning in the mouth, but it is still unclear whether the inflammation is a cause or effect of burning mouth syndrome.
There is also a correlation between autoimmune antibodies and the severity of burning mouth syndrome symptoms in people with Hashimoto’s thyroiditis (9).
Burning mouth syndrome may also be related to neuropathy of sensory nerves within the mouth (10).
One study found that people with BMS have increased neural apoptosis in the mouth which may contribute to symptoms (11).
3. Low striatal dopamine
Some people with burning mouth syndrome have been found to have lower levels of striatal dopamine (12, 13, 14). The striatum plays a role in pain perception.
The DRD2 gene (a dopamine receptor gene) 957C>T polymorphism has been linked to increased pain reception & may play a role in burning mouth syndrome (15).
5. HPA axis dysregulation
A few studies have found a link between high levels of cortisol and low levels of adrenaline and DHEA (precursor to testosterone and estradiol) in people with burning mouth syndrome (16, 17).
6. Immune suppression
People with burning mouth syndrome may have suppressed immune systems compared to healthy controls (16).
7. Sleep disorders
Having a sleep disorder increases the risk of developing burning mouth syndrome, especially in females (18, 19).
8. Circadian rhythm disorders
Some researchers suspect that dopamine-related circadian rhythm disorders may underly the link between burning mouth syndrome, depression and anxiety, HPA axis dysfunction, and pain perception (2, 20).
Who does it affect the most?
It is estimated that 0.7% to 4.6% of the US population has burning mouth syndrome. It is especially prevalent in women, the elderly, and those with anxiety or depression (21, 22).
What are the common treatments for burning mouth syndrome?
Prescription Clonazepam (Klonopin) can be applied topically to block GABA receptors in the mouth and reduce pain sensation (23). It can also be taken as a pill to reduce pain systemically.
However, this is just masking symptoms and the medication can have some unpleasant side effects like dry mouth, lethargy, and fatigue, and lead to dependence. Symptoms often return when the medication is discontinued (23).
Applying capsaicin (the component in chile peppers that makes them spicy) topically in the mouth can cause a temporary increased burning sensation, but afterward, it desensitizes pain receptors and reduces symptoms of burning mouth syndrome (24).
It is most often used as an oral rinse containing 0.02% capsaicin (25).
However, it causes stomach irritation in many people and again, is just masking symptoms (26).
3. Alpha lipoic acid
Alpha lipoic acid (ALA) is an antioxidant and cofactor for mitochondrial enzymes. It can be produced by the body but is often taken as a supplement.
Some research has found that taking an oral dose of 600 to 800 mg ALA per day for one or two months reduces the burning sensation in people with BMS. However, other studies found no difference compared to placebo, so more research is needed (26).
It appears to be especially effective when combined with 300 mg per day of gabapentin (27).
Amitriptyline is an antidepressant (tricyclic) that can have pain-relieving properties. It is sometimes prescribed for burning mouth syndrome and appears to be as effective as the benzodiazepine clonazepam (28).
However, common side effects include weakness and dry mouth, which could make mouth discomfort worse (28).
One small well-controlled study found that taking 12 mg per day of melatonin for 8 weeks helped reduce anxiety in people with BMS, but did not reduce pain (29).
Catuama is a blend of guarana, catuaba, ginger, and muira puama. Taking 2 capsules per day for 8 weeks has been shown to significantly reduce burning mouth syndrome symptoms compared to placebo (30).
7. Low-level laser therapy
Weekly laser therapy in the mouth for 9 or 10 weeks or 2x per week for two weeks may help reduce burning mouth syndrome pain, but not all studies have shown a difference from placebo (31, 32).
8. Cognitive behavioral therapy
Cognitive behavior therapy with a trained psychologist may be helpful for reframing thoughts and emotions about chronic pain (33). 12 to 15 sessions have been shown to reduce pain severity for people with burning mouth syndrome (34).
9. Addressing nutrient deficiencies
Burning mouth syndrome has been associated with B-vitamin deficiencies and zinc deficiency (4).
One study found over one quarter of people with burning mouth syndrome also had a zinc deficiency, and that repleting the deficiency with 14.1 mg of zinc daily for 6 months significantly improved burning mouth symptoms (35).
Other therapies with limited evidence include:
- 2% chamomile gel applied topically (36)
- Hypericum perforatum extract capsules (37)
- Olive oil spray enriched with lycopene (300 ppm) (38)
- Tongue protector + aloe vera gel (39)
- 10% urea topical treatment (40)
These therapies have been shown to reduce symptoms, but not more than placebo.
Erica is a registered dietitian nutritionist and lover of science and learning. She has a never-ending passion for education, and gladly spends her time writing & growing this blog! When she’s not at the computer, she can be found in the kitchen with her family, rocking out to good music and cooking up a storm.