How should I evaluate and treat a middle‑aged woman presenting with Burning mouth syndrome (persistent oral burning with normal examination)?

Evaluation and Management of Burning Mouth Syndrome

Initial Diagnostic Approach

Begin with a thorough oral examination to identify any visible mucosal lesions, followed by comprehensive laboratory testing to exclude secondary causes; most cases will be primary burning mouth syndrome requiring neuropathic pain management rather than inflammatory treatment. 1

Key History Elements

• Document the onset, duration, character, and location of the burning sensation, as primary BMS typically affects the tongue tip and anterior two-thirds bilaterally, along with lips, palate, and buccal mucosa 2, 1
• Specifically ask about dental procedures, facial trauma, or injections within the past 3-6 months, as post-traumatic neuropathic pain can develop in this timeframe and mimic primary BMS 1, 3
• Review all medications for potential pharmacological side effects causing oral burning 2, 3
• Assess for associated symptoms including dry mouth, taste alterations, depression, and quality of life impact 4, 3

Physical Examination Priorities

• Perform a complete oral mucosal examination looking for candidiasis, mucosal lesions, traumatic ulcerations from sharp tooth edges or ill-fitting dentures, or signs of thermal/chemical injury 1, 3
• Note that normal-appearing oral mucosa is characteristic of primary BMS; any visible pathology suggests a secondary cause 2, 1
• Examine for signs of autoimmune disorders (Sjögren's syndrome, sicca syndrome) that can manifest with oral burning 3

Essential Laboratory Workup

Order the following tests to exclude secondary causes 1, 3:

• Complete blood count with differential to identify anemia and hematological disorders 3
• Iron studies (ferritin, serum iron, TIBC) as iron deficiency frequently presents with burning tongue 3
• Vitamin B12 level (deficiency is a well-established cause) 1, 3
• Fasting glucose and HbA1c to evaluate for diabetes 1
• Thyroid function tests (TSH, free T4) as hyperthyroidism can cause tongue erythema and burning 1, 3
• Vitamin D 25(OH) level 1
• Consider riboflavin (B2), pyridoxine (B6), and zinc levels if nutritional deficiency is suspected based on dietary history 3

Additional Diagnostic Procedures

• Obtain oral swabs if fungal or bacterial infection is suspected (candidiasis diagnosed by scraping and KOH preparation) 3
• Consider tongue biopsy if suspicious lesions are present, unilateral pain, ulceration, or non-healing lesions to rule out malignancy 1
• Qualitative sensory testing may be performed if neuropathic etiology needs confirmation 3

Management Algorithm for Primary BMS

Weeks 0-2: Foundation Phase

Provide reassurance that the condition will not worsen—this is crucial and often represents a fundamental therapeutic element 1, 4. Explain that primary BMS is a disorder of peripheral nerve fibers with central nervous system changes, not an inflammatory or infectious process 2, 1.

• Initiate cognitive behavioral therapy (CBT) as the primary intervention to address psychological components that contribute to or exacerbate symptoms 1, 4
• Manage associated symptoms:
  • For xerostomia: encourage adequate hydration, limit caffeine, use saliva substitutes or moisture-preserving oral rinses 4
  • For taste disturbances: recommend regular oral hygiene with bland rinses (salt and sodium bicarbonate solution) 4
  • Advise avoiding crunchy, spicy, acidic, or hot foods that aggravate discomfort 4
  • Avoid oral care products containing alcohol or strong flavoring agents 4

Weeks 2-6: Pharmacological Intervention

If inadequate response to CBT and supportive measures:

• Start gabapentin 300 mg as first-line pharmacological treatment, which demonstrates efficacy in reducing burning sensation in 50% of patients 1, 4
• Alternative: Topical clonazepam or diazepam have shown some effect in managing symptoms 4
• Consider high-potency topical corticosteroids or viscous lidocaine for temporary symptomatic relief 4

Weeks 6-10: Combination Therapy

If partial response to gabapentin alone:

• Add alpha-lipoic acid to gabapentin, as this combination shows the best outcomes compared to monotherapy 4, 5
• If gabapentin is ineffective or not tolerated, consider switching to amitriptyline (which showed benefit in open-label studies) 2, 4

Beyond 10 Weeks: Refractory Cases

• Refer to pain specialist or neurologist if inadequate response after 4-6 weeks of combination therapy 4
• Evaluate for comorbid depression or anxiety and treat appropriately, as these frequently coexist with BMS 4
• Consider topical capsaicin, though it is limited by side effects 5

Management of Secondary BMS

When laboratory testing or examination identifies a specific cause:

• Treat iron, B12, B2, B6, or zinc deficiency with appropriate supplementation 1, 3
• Manage diabetes with glycemic control 1
• Control thyroid dysfunction with appropriate hormone therapy 1
• Discontinue offending medications when possible 1
• Treat oral candidiasis with antifungal therapy 1, 3
• Address autoimmune disorders (Sjögren's syndrome) with disease-specific management 3
• Correct traumatic factors such as sharp tooth edges or ill-fitting dentures 1

Critical Pitfalls to Avoid

• Do not prescribe apremilast for BMS—it is FDA-approved only for psoriasis, psoriatic arthritis, and Behçet's oral ulcers, and its mechanism (inhibiting phosphodiesterase-4 to down-regulate Th1/Th17 pathways) does not address the neuropathic pathophysiology of BMS 4
• Failing to provide adequate reassurance that the condition won't worsen is a major error, as this reassurance is often crucial for managing patient anxiety 2, 4
• Do not diagnose primary BMS without excluding secondary causes through proper laboratory workup and examination 1, 3
• Recognize that treatment failures are common and patients should be informed about the chronic nature of the condition with low likelihood of complete spontaneous remission 2, 4

Prognosis

The prognosis is generally poor with only a small number achieving complete resolution; however, combination approaches (CBT plus pharmacotherapy) generally outperform monotherapy 2, 4. Regular follow-up during symptomatic periods and psychological support are essential components of long-term management 4.