Burning Mouth Syndrome: A clinical challenge

Scratching her mouthIn the absence of clinical findings, Burning Mouth Syndrome (BMS) presents itself as a burning sensation of the oral mucosa. As such, it is considered to be one of the most difficult clinical challenges in the field of oral medicine.

BMS typically affects post-menopausal, middle-aged females with a prevalence of up to 15%. Recent research has pointed to a growing body of evidence suggesting that BMS may in fact be neuropathic in origin.

As an Oral and Maxillofacial Surgery Dental Core Trainee, I have frequently encountered patients complaining of a ‘burning mouth’. These patients are often overlooked due to our lack of understanding of the impact of their symptoms on their day-to-day life.

Initially, I found it challenging to manage their pain because, unlike other dental conditions, there is no visible pathology to treat. Now, with further exposure, I have come to appreciate the vital role we play as dental practitioners in recognising and managing the symptoms of this debilitating condition.

Diagnostic criteria for Burning Mouth Syndrome includes a history of chronic oral pain, unremarkable oral mucosa and the absence of a clinical cause.

1. Idiopathic chronic pain

Eliciting a thorough clinical history helps to distinguish between differing patterns of pain in patients with ‘burning mouth’ symptoms and the condition itself. Patients with the syndrome usually present with the following history:

Site Usually bilateral and anterior 2/3rd tongue
Less commonly palate and lips affected
Onset >50% spontaneous
30% attribute onset to after dental procedure, recent illness or medication
Character Burning, tingling, discomfort
Radiation  -
Associations Altered or perceived taste – bitter, metallic
Subjective dry mouth (xerostomia)
Mood changes – irritability, anxiety, depression
Time course Pain intensifying throughout the day, preventing but not disturbing sleep
Exacerbating/Relieving factors Exacerbated by stress, hot/spicy foodsRelieved by sleeping, occasionally topical analgesia
Severity Variable intensity

 

2. Clinically unremarkable oral mucosa

Oral inflammatory conditions such as lichen planus, geographic tongue and candidiasis can present with a burning mouth sensation. Treatment of the underlying condition usually resolves these symptoms. Often these patients are misclassified with BMS despite the diagnosis requiring the absence of a specific cause.

3. No identifiable medical or dental cause

As BMS is a diagnosis of exclusion, investigations should look for and exclude local and systemic treatable conditions causing ‘oral burning’ symptoms.

I. Bloods: FBC, B1, B6, B12, Iron, Folate, Ferritin and Serum Zinc

Nutritional deficiencies are associated with burning mouth symptoms but have also been found in patients with BMS. In particular, zinc supplements have been shown to reduce symptom intensity in BMS.

II. Candida microscopy and culture

Up to 60% of healthy individuals harbor candida in the oral cavity – a swab or smear can be carried out to quantify the presence of abnormally high rates of Candida. Although BMS patients have been shown to have a higher incidence of infection with Candida, this may be due to associated factors such as medication, xerostomia and unhygienic dentures. Interestingly, some studies show a remission of symptoms with antifungal therapy suggesting infection as a contributory factor of BMS.

III. Salivary flow rate

A reduction of salivary flow is commonly associated with oral burning sensations. Sufferers of BMS have been shown to have no histopathological changes to their major or minor salivary glands, although the quantity and quality of unstimulated saliva may be abnormal. Artificial salivary replacements may be useful in patients with decreased salivary flow rate, which may be due to Sjogren’s syndrome as a consequence of radiotherapy or a side effect of medication. Treat any underlying pathology that may be contributing to dry mouth and subsequently burning mouth symptoms.

IV. Patch testing

Dental allergens have been implicated in the aetiology of BMS, in particular denture base material polymethyl methacrylate and foaming agent sodium lauryl sulphate. Studies have revealed that reducing the excess monomer in methylmethacrylate can contribute to a reduction in burning symptoms.

V. Thyroid function test & glucose serum level

Researchers have noted a relationship between BMS and endocrine disorders such as hypothyroidism and diabetes mellitus with studies showing a 2-10% incidence of burning mouth symptoms in known diabetics. However, this could be due to the presence of candida, microangiopathy or neuropathy in these patients.

Patients complaining of a burning sensation of the oral mucosa remain a clinical challenge for dental professionals and researchers. Although there is difficulty in targeting curative treatment of BMS given the mechanism involved is not fully understood, effective symptom management is essential to enhance the quality of life of these patients.

There is growing use of neuromodulator medications such as Amitriptyline and ongoing research into the effects of antioxidant Alpha-lipoic acid, Benzodiazepines and the effectiveness of Cognitive Behavioural Therapy.

In light of planning the most effective treatment, it is first essential that dental practitioners are able to aptly recognise the symptoms of Burning Mouth Syndrome.

Jaimini Mehta, DCT in Oral and Maxillofacial Surgery

Acknowledgment:

Thanks to Mr A V Parbhoo (Consultant Oral & Maxillofacial Surgeon)

References & recommended reading:

1. Nasri-Heir, C., Zagury, J. G., Thomas, D. & Ananthan, S. Burning mouth syndrome: Current concepts. J. Indian Prosthodont. Soc. 15, 300–7 (2015).

2. Muzyka, Brian ,C De Rossi, S. S. A review of burning mouth syndrome. Cutis, Chatham 64.1, (1999).

3. Gurvits, G. E. & Tan, A. Burning mouth syndrome. World J. Gastroenterol. 19, 665–72 (2013).

4. Beneng, K. & Renton, T. Dental Update: Issue – Article: Pain Part 8: Burning Mouth Syndrome. (2016).

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