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. Icatibant and C1-inhibitor concentrate are specialist/hospital treatments used only according to local protocol, and evidence for icatibant in ACEi angioedema is inconsistent. Primary care priorities are: 999 for tongue, laryngeal or airway involvement, ABCDE management, IM adrenaline if there are airway, breathing or circulation problems consistent with anaphylaxis (repeat after 5 minutes if problems persist — Resuscitation Council UK), and early anaesthetics/ENT involvement. ACEi-induced angioedema can occur at any time during treatment, including after years of use, and is more common in people of Black African or Caribbean family origin. Stop the ACEi permanently and never restart; any switch to an ARB should be individualised and documented, as ARBs are not completely risk-free. 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 new unexplained lower cranial nerve palsy (IX, X, XI, XII) requires urgent neurological assessment and imaging of the brain, skull base and neck/carotid region (same-day emergency assessment if acute vascular features) to consider 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 — 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 (important sites for tongue SCC) 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. The tongue base is part of the oropharynx, not the oral cavity — HPV-associated oropharyngeal cancer should not be conflated with conventional lateral oral-tongue SCC. Referred otalgia 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 prompt serum electrophoresis, immunoglobulins and serum free light chains + 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. Acromegaly is rare, and delayed diagnosis (often by several years) is the norm, partly because macroglossia is attributed to other causes. A random GH is unhelpful; failure of GH to suppress on a glucose tolerance test (specialist test) confirms 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 four times a day, continued for 48 hours after lesions resolve; doses per BNF) 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.

Post-dental lingual nerve paraesthesia may improve spontaneously, and the timing and indication for microsurgical repair depend on the severity, mechanism, serial neurosensory assessment and specialist opinion. New persistent tongue/floor-of-mouth numbness, dysaesthesia or taste disturbance after dental treatment should be documented and discussed promptly with the dental/OMFS service; urgent referral is appropriate for complete sensory loss, severe dysaesthesia, suspected nerve transection, progressive symptoms or significant functional impact. 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. Not every post-injection altered sensation requires surgical referral within 48 hours. A red or red-white patch consistent with erythroplakia/erythroleukoplakia warrants an urgent referral for dental/oral assessment within 2 weeks at first presentation, regardless of duration (NICE NG12 says consider; this site's local safety policy is to refer); a dentist may then refer through the suspected cancer pathway if clinically suspicious. Malignant potential is determined once the lesion has been assessed and classified by an oral specialist. The practical clinical implication is: when examining the tongue, if you find a red patch that does not rub off with gauze → arrange urgent dental/oral assessment at that consultation. Do not wait, do not treat empirically, do not "review in 2 weeks."

Topical clonazepam for burning mouth syndrome is off-label and can cause sedation, dependence, falls and cognitive impairment; it should not be presented as routine GP treatment. Topical clonazepam, tricyclics, gabapentinoids and other neuropathic-pain strategies are specialist-directed (oral medicine) and individualised, after treatable causes have been excluded. 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 advanced immunosuppression. 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 (an HIV indicator condition), even when another cause of immunosuppression is known. 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 — recommended by NICE TA984 (June 2024) for wild-type or hereditary ATTR-CM in adults. 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 cause less bradykinin accumulation and rarely cause angioedema — but they are not completely risk-free, so the switch should be individualised and documented. 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, may maintain cardiovascular and renal protective effects with a lower, but not absent, angioedema risk. Sacubitril/valsartan (Entresto) contains an ARB, must never be combined with another ARB, and is contraindicated after angioedema related to previous ACE inhibitor or ARB therapy (SPC).

The tongue dorsum is the primary source of oral malodour (halitosis) — not, as commonly believed, the stomach or systemic disease. Most 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. HPV-positive oropharyngeal SCC (which includes tongue base and tonsillar SCC) is managed through the head-and-neck oncology pathway; prognostic discussions belong with the specialist team. GPs should avoid giving the impression that HPV SCC is "not serious" — it still requires intensive treatment and carries significant treatment morbidity.

BMS predominantly affects postmenopausal women, but HRT should not routinely be suggested for BMS — evidence is insufficient and it is not a standard treatment. HRT decisions follow the standard menopause assessment (NICE NG23) for its usual indications. 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. Stridor or other airway compromise → 999. Progressive dysphagia or rapidly progressive macroglossia → urgent airway assessment + speech and language therapy referral for dysphagia assessment.