Burning mouth syndrome (BMS) is a debilitating chronic condition characterized by orofacial pain that recurs daily for more than two hours per day for longer than three months.1 Patients refer to a burning sensation in the oral mucosa without visible or detectable mucosal, systemic abnormalities, or laboratory findings.
This condition can significantly impact the patient's quality of life; it most commonly affects middle-aged or older women but can happen in anyone. In 2003, Scala et al. proposed a distinction between "primary BMS," an idiopathic form, and "secondary BMS," caused by a local/systemic pathological condition.2,3
Causes of burning mouth syndrome
The etiology is unknown, but it is thought to be multifactorial. Possible causes include:
- Hormonal changes: BMS is more common in women and often worse around menopause. There are three theories regarding the link between hormonal changes and BMS. One is that hormonal changes can affect (decrease) saliva production due to a drop in estrogen and progesterone levels.4 Another is that hormonal changes can affect the nerves that innervate the oral tissues. These nerves transmit signals from the oral tissues to the brain, and when the nerves are affected, it can lead to a burning sensation in the mouth. Finally, hormonal changes can also affect the immune system, which can also cause burning sensations in the mouth.
- Dry mouth: Xerostomia can cause the oral mucosa to dry and easily irritate.
- Depression and anxiety: During times of stress, the receptors for serotonin may not be as active as they usually are; this means that serotonin is less effective at binding to these receptors and producing its effects. Since stress and anxiety can affect how the body perceives pain, this may be one way in which it can contribute to the development of BMS. Studies have found that people with BMS were more likely to have low levels of serotonin in their blood, especially noting that patients with BMS usually have lower levels of serotonin in the trigeminal nerve. Since serotonin is involved in regulating pain perception, it has been hypothesized that low serotonin levels may contribute to the development of BMS.5
- Nutritional deficiencies: Some studies have suggested that people with BMS are likelier to have low levels of vitamin B12, iron, and zinc in their blood. Patients who add these vitamins and minerals may experience a significant improvement in their symptoms.6
- Allergic reactions: Some people with BMS may be allergic to certain foods, toothpaste, or mouthwash.
- Medical conditions: Some medical conditions, such as diabetes, Sjögren's syndrome, and celiac disease, have been associated with BMS.
Signs and symptoms
The clinical appearance of the oral mucosa is usually normal. However, some people may have a dry mouth or a red/inflamed tongue.
The pain and burning sensation may be constant or intermittent, mild or severe.7 It is usually worse on the tongue but can also affect the gums, lips, and palate. Other symptoms may include:
- Taste disturbances: a metallic taste or loss of taste
- Dry mouth
- Sensitivity to hot or cold foods
- Irritation: the oral mucosa may be red, inflamed, or sore
Diagnostic tools
There is no single test that can diagnose BMS.8 The diagnosis is made based on the patient's history and clinical examination. Other tests that may be performed include:
- Blood tests: to rule out nutritional deficiencies or other medical conditions.
- Sialometry: to determine xerostomia.
- Taste test: to assess the patient's taste perception.
Differential diagnoses
Other conditions that can cause burning sensations in the mouth include:
- Glossodynia: a condition that causes a burning sensation on the tongue
- Allergic contact stomatitis
- Sjögren's syndrome
- Diabetes
Treatment and prognosis for BMS
There is no cure for BMS but treatments that can help relieve symptoms include:
- Topical medications, such as capsaicin cream or lidocaine gel, can help relieve the burning sensation
- Systemic medications, such as tricyclic antidepressants or anticonvulsants
- Behavioral therapy, such as stress management or cognitive-behavioral therapy, can help reduce psychological factors
- Holistic therapies, such as acupuncture or herbal medicine, may also be helpful
The prognosis for BMS is variable. Some people experience complete relief of symptoms, while others have ongoing symptoms.
References
1. Adamo D, Spagnuolo G. Burning mouth syndrome: an overview and future perspectives. Int J Environ Res Public Health. 2022;20(1):682. doi:10.3390/ijerph20010682
2. Orliaguet M, Misery L. Neuropathic and psychogenic components of burning mouth syndrome: a systematic review. Biomolecules. 2021;11(8):1237. doi:10.3390/biom11081237
3. Thoppay J, Desai B. Oral burning: local and systemic connection for a patient-centric approach. EPMA J. 2019;10(1):1-11. doi: 10.1007/s13167-018-0157-3
4. Dahiya P, Kamal R, Kumar M, Gupta R, Chaudhary K. Burning mouth syndrome and menopause. Int J Prevent Med. 2013;4(1):15-20.
5. Nagamine T. Serotonin paradox in burning mouth syndrome. J Clini Psychopharmacology. 2023;43(2):188-189. doi:10.1097/JCP.0000000000001661
6. Sun A, Chang JY, Wang YP, Cheng SJ, Chen HM, Chiang CP. Effective vitamin B12 treatment can reduce serum antigastric parietal cell antibody titer in patients with oral mucosal disease. J Formos Med Assoc. 2016;115(10):837-844. doi:10.1016/j.jfma.2016.05.003
7. Silvestre FJ, Silvestre-Rangil J, López-Jornet P. Burning mouth syndrome: a review and update. Rev Neurol. 2015;60(10):457-463.
8. Teruel A, Patel S. Burning mouth syndrome: a review of etiology, diagnosis, and management. Gen Dent. 2019;67(2):24-29. PMID: 30875303
