What is the workup for a patient presenting with a burning tongue sensation?

Workup for Burning Tongue Sensation

Begin with a thorough oral examination to identify visible mucosal lesions, followed by laboratory testing to exclude secondary causes (CBC, iron studies, B12, folate, glucose/HbA1c, vitamin D, thyroid function), and consider tongue biopsy or referral if suspicious lesions are present—most cases will be primary burning mouth syndrome (BMS) requiring neuropathic pain management rather than a curable underlying condition. 1, 2

Initial Clinical Assessment

History Documentation

• Onset, duration, and character of pain: Document whether the burning is continuous (typical of BMS) versus intermittent, and note if it worsens throughout the day 3, 1
• Location specificity: The tongue tip and anterior two-thirds are most commonly affected in BMS, often bilateral, but also assess lips, palate, and buccal mucosa 3, 2
• Aggravating factors: Ask specifically about acidic foods (tomatoes, orange juice), spicy/hot foods, prolonged speaking, stress, and fatigue 4, 5
• Relieving factors: Cold foods, work activities, and leisure often diminish BMS symptoms 5
• Associated symptoms: Systematically inquire about dry mouth (xerostomia), metallic or altered taste (dysgeusia), diminished taste sensations, depression, anxiety, and quality of life impact 3, 2, 4
• Demographic context: BMS predominantly affects peri- and post-menopausal women (onset typically 3-12 years after menopause) and is uncommon before age 30 (age 40 for men) 2, 4

Physical Examination

• Oral cavity inspection: Look for normal-appearing mucosa (typical of primary BMS) versus visible lesions, ulceration, induration, erythema, white patches, or non-healing areas 1, 2
• Assess for traumatic factors: Check for sharp edges of residual tooth roots/crowns, ill-fitting dentures, or thermal/chemical injury 2
• Candidiasis evaluation: Examine for white plaques that can be scraped off, erythematous patches, or angular cheilitis 2
• Neck examination: Palpate for lymphadenopathy, which may indicate infectious or malignant processes 1
• Cranial nerve assessment: If neuropathic pain is suspected, perform light touch sensitivity testing in all three trigeminal divisions 6

Laboratory Workup

Essential Blood Tests

• Complete blood count (CBC) with differential: To identify anemia, which commonly causes oral burning symptoms 2
• Iron studies: Order ferritin, serum iron, and total iron-binding capacity (TIBC) as iron deficiency anemia frequently presents with burning tongue 2
• Vitamin B12 level: Deficiency is a well-established cause of secondary BMS 2
• Folate level: Nutritional deficiencies contribute to oral burning 5
• Fasting glucose and HbA1c: Diabetes can manifest with burning tongue and xerostomia, and undiagnosed diabetes may present this way 2, 7
• Vitamin D 25(OH): Deficiency has been associated with burning tongue symptoms 2, 7
• Thyroid function tests (TSH, free T4): Hyperthyroidism can cause tongue erythema and burning 2

Additional Testing Based on Clinical Suspicion

• Oral candidiasis confirmation: If white lesions are present, perform scraping with KOH preparation for microscopic examination 2
• Autoimmune screening: If Sjögren's syndrome or other autoimmune disease is suspected based on dry mouth and systemic symptoms, consider anti-SSA/SSB antibodies 2

Specialized Diagnostic Procedures

When to Biopsy

• Mandatory for suspicious lesions: Any unilateral pain with ulceration, induration, or non-healing lesions requires biopsy to rule out malignancy, especially in patients with tobacco use, alcohol consumption, or HPV risk factors 1
• Consider for diagnostic uncertainty: If mucosal abnormalities are present or the diagnosis remains unclear after initial workup 2
• Research context: Tongue biopsies in BMS patients show significantly lower density of epithelial nerve fibers compared to controls, supporting the neuropathic etiology, though this is not routinely performed clinically 2, 4, 8

Advanced Testing (Selective Use)

• Qualitative sensory testing (QST): Consider if neuropathic etiology is suspected to quantify sensory abnormalities and differentiate peripheral versus central mechanisms 6, 2
• Neurophysiological testing: May be used in research settings to confirm peripheral nerve fiber disorder with central nervous system changes 2
• MRI of brain and trigeminal nerve: Indicated if post-traumatic trigeminal neuropathic pain is suspected (continuous pain with numbness after dental procedures or trauma) to exclude structural lesions or nerve compression 6

Diagnostic Algorithm

Step 1: Categorize Based on Oral Examination

• Normal-appearing mucosa with burning pain: Proceed to exclude secondary causes through laboratory testing; if negative, diagnose primary BMS 1, 2
• Visible lesions present: Perform biopsy to rule out malignancy, especially if unilateral, indurated, or non-healing 1
• Evidence of candidiasis: Confirm with KOH preparation and treat with antifungal therapy before considering BMS 2
• Traumatic factors identified: Address dental issues (sharp edges, ill-fitting dentures) and reassess after correction 2

Step 2: Interpret Laboratory Results

• Anemia, B12, folate, or iron deficiency: Treat deficiency and monitor for symptom resolution—this is secondary BMS 2
• Elevated glucose/HbA1c: Manage diabetes and address xerostomia; burning tongue may improve with glycemic control 2, 7
• Vitamin D deficiency: Supplement and reassess symptoms 2, 7
• Thyroid dysfunction: Treat underlying thyroid disorder 2
• All laboratory tests normal: Diagnose primary BMS and initiate neuropathic pain management 2

Common Pitfalls to Avoid

• Do not dismiss as psychogenic without thorough evaluation: While depression and anxiety are common comorbidities in BMS, they do not fully explain the syndrome, which has a demonstrated neuropathic basis 3, 4
• Do not overlook malignancy in high-risk patients: Older patients with tobacco/alcohol history or younger patients with HPV risk factors presenting with unilateral tongue pain require complete head and neck examination and biopsy of suspicious lesions 3, 1
• Do not assume all burning tongue is BMS: Systematically exclude secondary causes (candidiasis, nutritional deficiencies, autoimmune disease, medication side effects) before diagnosing primary BMS 2
• Recognize that spontaneous remission is rare: The prognosis for primary BMS is poor with only a small number resolving fully, though reassurance that symptoms will not worsen is crucial for patients 3

Management Considerations After Diagnosis

Primary BMS Treatment

• Reassurance and education: Inform patients that while the condition is chronic, it will not worsen—this is often crucial for coping 3
• Cognitive behavioral therapy (CBT): Should be initiated early to address psychological components, improve coping strategies, and enhance quality of life 6, 1
• Pharmacologic options: Gabapentin (first-line neuropathic agent), alpha-lipoic acid, topical clonazepam or diazepam 1
• Realistic expectations: Current treatments are palliative only and may not be much better than placebo; few studies report relief without intervention 4

Secondary BMS Treatment

• Address underlying cause: Treat nutritional deficiencies, manage diabetes, control thyroid dysfunction, discontinue offending medications, or treat candidiasis 2
• Xerostomia management: If dry mouth is contributing, use saliva substitutes, increase hydration, and address underlying causes 7