ACE inhibitor-induced angioedema is distinct from allergic (IgE-mediated) angioedema in mechanism and treatment — it is caused by accumulation of bradykinin (which ACE normally degrades; ACE inhibition prevents degradation → bradykinin accumulates → increased vascular permeability → angioedema). Because the mechanism is bradykinin-mediated rather than histamine-mediated, antihistamines and corticosteroids are ineffective. The specific treatment is icatibant (a bradykinin B2 receptor antagonist — Firazyr 30 mg SC injection) or C1-esterase inhibitor concentrate (Berinert IV). ACEi-induced angioedema can occur at any time during treatment — most commonly in the first month, but cases have occurred after years of use. It is more common in Afro-Caribbean patients (3× higher prevalence). The key management principle is: stop the ACEi permanently (rechallenge has a 30% re-occurrence rate) and never restart — switch to an ARB (angiotensin receptor blocker) if antihypertensive effect is needed, as ARBs very rarely cause angioedema. The CN XII (hypoglossal nerve) anatomy is important for understanding tongue deviation: the hypoglossal nerve innervates the intrinsic and extrinsic tongue muscles. When CN XII is damaged on one side, the ipsilateral tongue muscles are weak. On protrusion, the unaffected contralateral muscles push the tongue toward the weak side — therefore the tongue deviates toward the side of the lesion. This is the opposite of CN VII palsy (facial nerve — the face deviates away from the lesion). Remembering "tongue goes to the trouble" helps: the tongue points toward the damaged nerve side. Any isolated lower cranial nerve palsy (IX, X, XI, XII) without an obvious cause (trauma, infection) must prompt urgent MRI to exclude skull base pathology (jugular foramen tumour — glomus jugulare, nasopharyngeal carcinoma, meningioma, metastasis).

Geographic tongue generates significant patient anxiety when first discovered or when a patient reads about it online — patients often fear cancer or infection and present alarmed. The GP's role is to provide unambiguous reassurance: geographic tongue is a benign, common, completely harmless condition with no malignant potential. The explanation that it is caused by cyclical changes in the pattern of filiform papillae loss and regrowth (hence "migratory") usually satisfies most patients. The psoriasis association is worth mentioning because patients with psoriasis have a significantly higher prevalence of geographic tongue — both share dysfunction of the same inflammatory pathway (IL-36 cytokine signalling), and geographic tongue can be considered an oral manifestation of the same underlying immune dysregulation as psoriasis. Plummer-Vinson syndrome (also called Patterson-Brown-Kelly syndrome in the UK) deserves specific attention — it is the combination of iron deficiency anaemia, dysphagia from a post-cricoid oesophageal web, glossitis (smooth red tongue), koilonychia (spoon-shaped nails), and angular cheilitis. It predominantly affects middle-aged women. Critically, the post-cricoid oesophageal web in Plummer-Vinson syndrome carries a significantly elevated risk of hypopharyngeal or oesophageal squamous cell carcinoma (approximately 10% lifetime risk) — this is why any patient presenting with iron deficiency + dysphagia + glossitis needs gastroscopy to identify and treat the web, and surveillance thereafter. Iron replacement resolves the glossitis and may resolve the web in early cases. Burning mouth syndrome is one of the most challenging conditions to manage in primary care — it is a neuropathic pain condition of the oral mucosa with a complex pathophysiology (peripheral small fibre neuropathy + central sensitisation + psychological factors) and limited treatment response. The key is diagnosis of exclusion — every identifiable treatable cause (candidiasis, nutritional deficiency, dry mouth, denture allergy, contact stomatitis from toothpaste flavourings or preservatives) must be identified and corrected before BMS is diagnosed. Many patients diagnosed with BMS actually have one of these treatable conditions.

The gauze retraction technique for lateral tongue examination is the most important skill in oral cancer detection and is systematically underpractised in primary care — without physically grasping the tongue tip with gauze and pulling it laterally, the lateral and ventrolateral borders (where 40% of tongue SCC arises) are completely invisible. It is physically impossible to see the lateral tongue border simply by asking the patient to open their mouth and protrude the tongue. The technique takes 15 seconds: tear a small piece of gauze (or use a tissue), grasp the tongue tip with the non-dominant hand, retract laterally to the patient's left, inspect the right lateral border, then retract to the right and inspect the left lateral border. Any ulceration, induration, leukoplakia, erythroplakia, or unexplained colour change should be visible. This should be a routine part of any oral examination in patients over 40 with mouth symptoms. Referred otalgia (referred pain to the ear) from tongue or oropharyngeal cancer is one of the most important clinical features to recognise — the sensory innervation of the tongue and oropharynx overlaps with the auricular branches of CN V3 and CN IX, meaning that tumours in this region can cause referred pain perceived in the ipsilateral ear. Any adult with persistent unilateral ear pain without obvious otological cause (intact tympanic membrane, normal otoscopy) warrants oral and oropharyngeal examination to exclude tongue base or tonsillar cancer. This is a known presentation pattern of HPV-positive oropharyngeal SCC and is one of the reasons these cancers are frequently delayed in diagnosis. Periorbital purpura with macroglossia is a highly specific presentation of systemic amyloidosis — the purpura is caused by amyloid infiltration of dermal blood vessel walls, making them fragile, and occurs characteristically around the eyes after minor trauma (Valsalva, vomiting). This combination of periorbital purpura + macroglossia + carpal tunnel syndrome in an older patient should immediately prompt serum free light chains + urine Bence Jones protein + haematology referral.

The IGF-1 test for acromegaly is the appropriate first-line screening test (not GH, which fluctuates throughout the day). Acromegaly causes macroglossia through GH-mediated tissue overgrowth affecting all soft tissues including the tongue, lips, and parotid glands. Associated features to look for: enlarged hands and feet (rings/shoes no longer fitting), frontal bossing, prognathism, interdental spacing, hypertension, carpal tunnel syndrome, type 2 diabetes, sleep apnoea. The prevalence of acromegaly is approximately 6 per 100,000 — it is rare, but delayed diagnosis (mean 7–10 years from symptom onset) is the norm, partly because macroglossia is attributed to other causes. A fasting GH <0.4 ng/ml effectively excludes acromegaly; elevated IGF-1 = pituitary MRI + endocrinology referral. Oral candidiasis causing burning mouth syndrome is an important diagnosis to exclude — low-grade, erythematous candidiasis (the atrophic form) can cause exactly the burning pain pattern of BMS without the visible white plaques of pseudomembranous candidiasis. This form of candidiasis is extremely easy to miss — the mucosa appears reddened and slightly glazed but not specifically abnormal to the untrained eye. A therapeutic trial of fluconazole 50 mg OD × 7 days (or nystatin suspension QDS × 2 weeks) can be both diagnostic and therapeutic — complete resolution of burning with antifungal treatment confirms candidal aetiology and should change the diagnosis from BMS to oral candidiasis. This trial should be performed before making a definitive diagnosis of BMS.

The lingual nerve injury 48-hour window is critical and is not widely known in primary care — microsurgical repair of lingual nerve injuries following wisdom tooth extraction achieves significantly better sensory recovery when performed within 3 months of injury, and ideally within 6 weeks. However, the initial referral should be made within 48 hours of injury so that the OMFS team can assess the extent of damage, document it accurately, and arrange repair if indicated. The clinical consequences of permanent lingual nerve damage include: permanent numbness of the ipsilateral anterior two-thirds of tongue, floor of mouth, and lingual gingiva; loss of taste from the anterior two-thirds of tongue (chorda tympani component); and chronic neuropathic pain (dysaesthesia). These significantly affect quality of life, and the medicolegal implications of delayed or absent referral are considerable. Any patient who reports tongue numbness or altered taste following a lower third molar extraction or inferior alveolar nerve block should be referred to OMFS the same day. The erythroplakia 2WW threshold being immediate (regardless of duration) reflects the high malignant transformation rate — up to 50% of erythroplakic lesions are either already carcinoma in situ or SCC at the time of biopsy. Waiting 3 weeks (as with leukoplakia or ulcers) is not appropriate for erythroplakia — any red non-wipeable mucosal patch should be 2WW-referred at the first presentation. The practical clinical implication is: when examining the tongue, if you find a red patch that does not rub off with gauze → 2WW at that consultation. Do not wait, do not treat empirically, do not "review in 2 weeks."

The clonazepam "swish and spit" (dissolve and spit) technique for burning mouth syndrome is the most evidence-based topical treatment available — several small RCTs have shown significant pain reduction with this approach. The mechanism is local binding of clonazepam to GABA-A receptors in the oral mucosal sensory fibres, reducing nociceptive input. The instruction to NOT swallow is essential — if swallowed, systemic benzodiazepine absorption occurs, with sedation, dependence risk, and drug interaction. The topical use has negligible systemic absorption and therefore minimal systemic side effects. Clonazepam 0.5 mg tablets (or 0.25 mg half-tablets) are held on the tongue or rolled around the mouth for 3 minutes TDS before meals. Response is seen within 2–4 weeks. This approach can be initiated in primary care before specialist referral. Hairy leukoplakia as a marker of immunosuppression is one of the most important oral findings a GP can make — it is caused by Epstein-Barr virus (EBV) replication in the oral mucosal epithelium, which only occurs when cellular immunity is suppressed. In the pre-ART era, hairy leukoplakia was a reliable marker of HIV infection with CD4 count below 300 cells/µl. In the current era, the same principle applies: EBV-driven hairy leukoplakia indicates significant cellular immunosuppression from whatever cause. The primary cause to exclude is HIV — an HIV test must be offered and strongly recommended to any patient with hairy leukoplakia who does not have another identified cause of immunosuppression. The lesion itself is asymptomatic and does not require treatment in most cases (it will resolve with ART in HIV-positive patients), but its significance lies entirely in what it reveals about the patient's immune status.

The distinction between AL amyloidosis and ATTR amyloidosis is increasingly important clinically as specific treatments have become available for ATTR. Wild-type ATTR (transthyretin) amyloidosis is the most common form of cardiac amyloidosis in older adults — it causes a restrictive cardiomyopathy that is frequently misdiagnosed as hypertensive heart disease or HFpEF. Tafamidis (Vyndaqel) is a disease-modifying treatment that stabilises the TTR protein and reduces cardiac amyloid deposition — NICE approved in 2020. GPs who encounter macroglossia in an older patient with unexplained cardiac failure and thick walls on echocardiography should consider amyloidosis and ensure haematology/cardiology review. The periorbital purpura + macroglossia combination is almost diagnostic of AL amyloidosis. The ACEi-to-ARB switch principle is one of the most important medication management decisions following ACEi-induced angioedema — ARBs block angiotensin II at the AT1 receptor without affecting the bradykinin pathway, so they do not cause bradykinin accumulation and very rarely cause angioedema (estimated 0.1% rate vs 0.5% for ACEi). The patient and their subsequent GP must be clearly informed that ACEi must never be restarted — this must be documented in the patient's allergy record. The switch from ramipril to candesartan, for example, maintains cardiovascular and renal protective effects while eliminating the angioedema risk. In patients where the ARB is also needed for its specific indication (e.g., heart failure with ACEi intolerance), the combination of ARB + sacubitril/valsartan (Entresto) may be appropriate under cardiology guidance.

The tongue dorsum is the primary source of oral malodour (halitosis) — not, as commonly believed, the stomach or systemic disease. Approximately 90% of oral malodour in otherwise healthy individuals originates from the anaerobic bacteria that colonise the posterior tongue dorsum, particularly in the crypts between the circumvallate papillae. These bacteria degrade sulphur-containing proteins (from food debris, desquamated epithelial cells, and saliva) to produce volatile sulphur compounds (VSCs: hydrogen sulphide, methyl mercaptan, dimethyl sulphide). Tongue brushing or scraping reduces VSC production by removing the bacterial substrate from the tongue surface. A tongue scraper is more effective than a toothbrush for VSC reduction (Haraszthy et al. 2007) and reduces malodour by approximately 75%. This is highly relevant to clinical practice — many patients attending for halitosis or recurrent sore tongue will benefit from this simple advice. The HPV oropharyngeal SCC prognosis point is clinically important for consultations with newly diagnosed patients — HPV-positive oropharyngeal SCC (which includes tongue base and tonsillar SCC) has significantly better prognosis than tobacco/alcohol-related oral SCC, with 5-year survival of approximately 80% vs 40%. This difference is attributed to the better inherent radiosensitivity of HPV-positive tumours. Informing patients with HPV SCC about the better prognosis compared to tobacco-related cancers is an important communication skill — it significantly reduces the distress associated with a cancer diagnosis and helps patients understand their treatment options. However, GPs should also avoid giving the impression that HPV SCC is "not serious" — it still requires intensive chemoradiotherapy and carries significant treatment morbidity.

The HRT consideration in BMS in postmenopausal women is an underutilised management option — BMS has a strong association with the menopause (it predominantly affects postmenopausal women, particularly in the first 3 years after menopause), and oestrogen deficiency has been proposed as a contributing factor through its effects on peripheral sensory nerve function and mucosal integrity. Small studies have suggested that HRT improves BMS symptoms in some postmenopausal women. Given that HRT is already indicated for many menopausal women for vasomotor symptoms and osteoporosis prevention, it is clinically reasonable to discuss HRT in a postmenopausal woman with BMS — the dual benefit may be achievable. The decision to prescribe HRT involves the standard menopause risk-benefit discussion (NICE NG23) and should not be initiated for BMS alone without considering the full menopause assessment. The swallowing and airway monitoring in macroglossia is a clinical safety principle — macroglossia from any cause can progress to cause obstructive sleep apnoea (tongue falling back during sleep → airway obstruction), dysphagia (difficulty manipulating food bolus), and in severe cases, at-rest airway compromise. The STOP-BANG questionnaire or Epworth Sleepiness Scale should be applied to all patients with macroglossia to screen for OSA. Any patient with macroglossia + excessive snoring + daytime somnolence warrants overnight oximetry or formal sleep study referral. Progressive dysphagia with macroglossia → CT neck to assess airway compromise + speech and language therapy referral for dysphagia assessment.