Burning Mouth Syndrome, Burning Tongue (Glossodynia)

CHAPTER 44

Burning Mouth Syndrome, Burning Tongue

(Glossodynia)

Presentation

The patient is very uncomfortable because of a painful sensation of the tongue or mouth. The pain is variably described as a burning, tingling, hot, scalded, or numb sensation, the magnitude of which is similar to a toothache. The sensation occurs most commonly on the anterior two thirds and tip of the tongue but may include the upper alveolar region, palate, lips, and lower alveolar region. Burning mouth syndrome (BMS) affects women seven times more frequently than men. It particularly affects the middle-aged and elderly population (mean age 60 years) and has not been reported in children.

There may be xerostomia (dry mouth) (Figure 44-1), dental disease or dentures, geographic tongue (Figure 44-2), smooth tongue (Figure 44-3), candidiasis (see Chapter 53), or no visible explanation for the pain.

Figure 44-1 Xerostomia. (From Drage LA, Rogers RS: Burning mouth syndrome. Dermatol Clin 21:135-145, 2003.)

Figure 44-2 Geographic tongue. (From Bolognia J, Jorizzo J, Rapini R: Dermatology. St Louis, 2003, Mosby.)

Figure 44-3 Smooth tongue. (From Drage LA, Rogers RS: Burning mouth syndrome. Dermatol Clin 21:135-145, 2003.)

What To Do:

Determine the type of BMS the patient has by the character of her symptoms.

In type 1 (35%), the patient has daily pain that is not present on awakening but progresses throughout the day and is most severe during the evening hours. This type of pain is usually not associated with psychiatric disorders.

In type 2 (55%), the patient awakens with a constant daily pain. This type of pain is associated with psychiatric conditions, especially chronic anxiety.

In type 3 (10%), the patient has intermittent pain with symptom-free intervals. The pain occurs in unusual sites, such as the buccal mucosa, floor of the mouth, and throat. This type of pain is associated with allergies to food additives or flavorings.

Try to determine if the patient’s pain is associated with systemic, local, psychiatric or psychological, or idiopathic factors.

The most common associations include psychiatric or psychological disorders, xerostomia, nutritional deficiencies, allergic contact stomatitis, denture-related factors, parafunctional behavior (e.g., bruxism and tongue thrusting), candidiasis, diabetes mellitus, and drug-related BMS. There may be more than one cause.

A history should include the duration of pain, its character, its pattern, and the site of involvement. Ask about depression, anxiety, and fear of cancer. Are there any exacerbating factors, such as food, mouthwash, mints, lip cosmetics, or smoking? Is there a relationship of the pain to denture use, dental work, tongue thrusting, bruxism, or jaw clenching? Look into medication use that has xerostomic potential.

A general physical examination should be performed with emphasis on a thorough oral evaluation, and, when appropriate, reassurance that cancer is not present. Look for erythema, ulcers, glossitis, atrophy, candidiasis, dentures, geographic tongue, lichen planus, and xerostomia.

When a psychiatric disorder is suspected, referral for psychiatric evaluation, medication, and psychotherapy evaluation may play a role in alleviating the symptoms. Antidepressants and anxiolytics with less anticholinergic impact (hence, less xerostomia) are preferred. Serotonin reuptake inhibitors may be a good choice in this setting. Medical management may also include tricyclic antidepressants (amitriptyline 10 to 150 mg per day), benzodiazepines (clonazepam 0.25 to 2 mg per day), or anticonvulsants (gabapentin 300 to 1800 mg per day).

Reassurance that cancer is not present should be stated clearly and repeatedly.

Potential dental problems require evaluation of any dental work, dentures, and parafunctional behavior (e.g., bruxism) by a specialist. Avoidance of irritants, removal of dentures at night, treatment of dentures with anticandidal agents, and a review of dental hygiene should occur.

When suspected, an appropriate laboratory workup for nutritional deficiencies should be initiated. Replacement of iron, B₁₂, folate, or zinc should occur in patients with documented deficiencies.

It is reasonable to provide empiric replacement of vitamins B₁ (100 mg, once a day) and vitamin B₆ (50 mg, 3 times a day) for 4 weeks.

Typically, empiric treatment for oral candidiasis is offered to the patient with BMS. One effective treatment regimen includes the use of oral fluconazole (Diflucan), 100 mg, prescribe a total of 15 pills: Day 1, the patient takes two pills; days 2 to 7, one pill qd; days 8 to 21, one pill every other day.

If the patient is not known to have diabetes mellitus, a fasting blood glucose level should be obtained. Control of diabetes mellitus may lead to decreased BMS. Change of the patient’s diabetic medications can sometimes be helpful.

Dry mouth can be helped by discontinuing or substituting medications with potential for causing xerostomia. Artificial saliva substitutes may be helpful. Available without prescription are MouthKote (spray), Moi-Stir spray (and swabs), and Optimoist (spray). Sialogogues such as pilocarpine (Salagen), 5 mg tid, are sometimes used, as well as sugar-free candy, gum, and beverages.

When the cause is unclear (idiopathic), in addition to empirical treatment with B-complex vitamins and anticandidal agents, patients should be instructed to discontinue all potentially irritating substances, such as alcohol-based mouthwashes, cinnamon, mint products, and smoking. Doxepin is often prescribed in doses up to 75 mg qd for its antianxiety and antidepressant affects. At higher doses, doxepin has a greater potential for cardiac arrhythmia and xerostomia.

You can provide symptomatic relief with a 1:1 mixture of diphenhydramine (Benadryl) elixir and kaolin-pectin (Kaopectate), or prescribe viscous lidocaine (Xylocaine) 15 to 20 mL, swish and spit q3h.

If the onset is recent, an alternative approach is to have the patient rinse with a topical anesthetic mouth rinse for 3 minutes and then apply capsaicin gel (0.025%) for 3 minutes. This is repeated morning and evening for 6 weeks. (This works best in neuropathic pain of recent onset.)

If the cause is uncertain and persists, refer the patient for a comprehensive medical evaluation.

What Not To Do:

Do not assume that the patient has a purely psychiatric cause for her pain until all other potential causes have been considered and appropriate consultations have been made.

Discussion

Burning mouth syndrome is the occurrence of oral pain in a patient with a normal oral mucosal examination.

Psychiatric disease is a common underlying factor in patients with BMS. At least one third of patients may have an underlying psychiatric diagnosis, most commonly depression or anxiety disorders. A phobic concern regarding cancer is also prominent in 20% of patients. Remember that depression and psychological disturbance are common in chronic pain populations and may be secondary to the chronic pain, rather than the cause of BMS. In addition, many of the medications that are used to treat psychiatric disease can cause xerostomia and exacerbate BMS.

Dry mouth is a frequent complaint among BMS patients. Drug-related xerostomia is common and can occur with many medications, including tricyclic antidepressants, benzodiazepines, monoamine oxidase inhibitors, antihypertensives, and antihistamines. Connective tissue diseases, such as Sjögren syndrome, or sicca syndrome, can cause xerostomia, as can a history of local irradiation or diabetes mellitus. Even stress and anxiety can lead to a dry mouth.

Because of rapid cell turnover and trauma, the oral cavity is especially sensitive to nutritional deficiencies and may be the first indicator of such a problem. Iron-deficiency anemia, pernicious anemia (an autoimmune B₁₂ deficiency), zinc deficiency, and B-complex vitamin deficiency have all been reported to cause BMS.

Flavoring or food additives have been implicated as possible allergens in BMS. Cinnamon aldehyde (cinnamon), sorbic acid, tartrazine, benzoic acid, propylene glycol, menthol, and peppermint have all been identified as potential causes of mouth pain.

Denture-related pain is usually caused by faulty design, irritation, or parafunctional behavior. Candidiasis can also contribute to denture-related pain. Most BMS patients with dentures or significant dental work benefit from referral for a formal dental consultation to assess dental work, dentures, occlusion, and the need for modification or replacement.

Candidiasis is reported as a causative factor in 6% to 30% of patients with BMS. The mucosal alterations typically seen with candidiasis (thrush) may be minimal or absent. Candidal overgrowth occurs with xerostomia, corticosteroid treatment, antibiotic treatment, denture use, and diabetes mellitus. Empiric treatment for oral candidiasis is often prescribed to patients with BMS.

Approximately 5% of BMS patients have diabetes mellitus. BMS is the second most common oral complaint after xerostomia in a study of diabetic patients. Improved control of their diabetes mellitus may lead to improvement or cure of BMS.

The angiotensin-converting enzyme inhibitors enalapril, captopril, and lisinopril can cause scalded mouth or BMS. There is often improvement with reduction or discontinuation of the medication.

Although they are often regarded as asymptomatic variants of normal, multiple studies have shown geographic, fissured, or scalloped tongues more frequently in patients with tongue pain. When these patients complain of pain, technically they do not fit under the rubric of BMS but can be treated as such and should be reassured about their possibly increased fear of cancer.

Identification of correctable causes of BMS should be emphasized, and psychiatric causes should not be invoked without thorough evaluation of the patient. Such a thoughtful and structured evaluation has been associated with improvement in approximately 70% of these patients.

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