Burning mouth in a patient with multiple medications
A 68-year-old woman presents with a 6-month history of burning in the tongue and palate, worse in the evening and relieved by eating. She has type 2 diabetes (HbA1c 8.1%), hypertension and depression. Her medications are metformin, ramipril, amlodipine and sertraline. She wears an upper complete denture and a lower partial denture; the dentures are 12 years old. Examination shows a smooth, erythematous tongue with loss of papillae, angular cheilitis, and a generalised erythematous palate under the denture. There are no ulcers or white patches. She has no cervical lymphadenopathy.
1. What is your differential diagnosis for the burning symptoms, and how would you distinguish between them clinically and with investigations?
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Differential diagnosis:
- Nutritional deficiency: B12, folate, iron deficiency can cause a smooth, erythematous tongue (atrophic glossitis), angular cheilitis and burning. Diabetes and metformin increase the risk of B12 deficiency.
- Diabetes-related oral candidiasis: erythematous candidiasis under the denture and at the angles; burning is common.
- Denture-related stomatitis: chronic erythema under the denture, often candidal.
- Dry mouth (xerostomia): medications (sertraline, amlodipine, ramipril) and diabetes can cause it; burning is a common symptom.
- Burning mouth syndrome: a diagnosis of exclusion; often bilateral, no visible lesions, worse in the evening, relieved by eating.
- Oral lichen planus or lichenoid reaction: usually has striae or erosions; sertraline and other drugs can cause lichenoid reactions.
- Diabetes-related neuropathy or vitamin deficiency.
Investigations:
- FBC, ferritin, B12, folate, HbA1c, U&E, LFTs.
- Swab or smear for candidiasis (Gram stain or culture).
- Consider salivary flow assessment.
- Review medications for xerostomia and lichenoid potential.
The key is that burning mouth is a symptom, not a diagnosis; the visible signs (atrophic glossitis, angular cheilitis, denture erythema) point to a treatable cause rather than primary burning mouth syndrome.
2. How would you manage her, and how would you prioritise the interventions?
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Prioritised management:
- Treat candidiasis: topical antifungal (e.g., miconazole gel or nystatin) and denture hygiene; consider systemic fluconazole if extensive. Address angular cheilitis with antifungal/antibacterial cream.
- Correct nutritional deficiencies: check B12, folate and iron; replace as indicated. Metformin is associated with B12 deficiency, so this is a strong possibility.
- Address denture problems: the dentures are 12 years old and likely ill-fitting; refer for new dentures and advise removal at night, cleaning and soaking.
- Optimise diabetes control: liaise with her GP/diabetes team; poor glycaemic control predisposes to candidiasis and xerostomia.
- Review medications: discuss with her GP whether any contributing drug (e.g., sertraline, amlodipine) can be changed, but do not stop prescribed medication unilaterally.
- Saliva substitutes and hydration advice for xerostomia.
- Reassurance and review: if symptoms persist after correcting causes, consider burning mouth syndrome and manage supportively (e.g., cognitive behavioural therapy, low-dose clonazepam under specialist guidance).
The principle is to correct identifiable causes before labelling it burning mouth syndrome.
3. She returns 8 weeks later with persistent symptoms despite antifungal treatment and new dentures. What would you do next?
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Next steps:
- Re-examine: look for missed lesions (erosions, striae, ulcers), check denture fit and hygiene, and assess for xerostomia.
- Repeat investigations: repeat FBC, B12, folate, ferritin, HbA1c; consider zinc and vitamin D; check thyroid function.
- Consider a biopsy if there is any persistent erythema, ulceration or asymmetry, to exclude dysplasia or malignancy; a smooth tongue without focal lesion may not need biopsy, but persistent unilateral symptoms should be investigated.
- Review medications again with the GP, especially sertraline (lichenoid reaction) and any xerostomic drugs.
- Consider referral to oral medicine for specialist assessment, including patch testing for denture materials if a contact reaction is suspected.
- Address psychological factors: burning mouth syndrome is associated with anxiety and depression; consider cognitive behavioural therapy or specialist input.
The judgement call is to avoid endless empirical treatment without a diagnosis, while recognising that burning mouth syndrome is a diagnosis of exclusion and may need multidisciplinary management.