👃 Anosmia is the complete loss of smell. While it can be an early sign of neurological disease, the commonest causes are ENT-related, particularly viral infections and chronic rhinosinusitis. A structured approach is key to avoid missing serious pathology while managing the majority of benign cases effectively.

📖 Clinical Approach

History: Onset (sudden vs gradual), duration, associated nasal symptoms (obstruction, rhinorrhoea, facial pain), recent viral illness, head trauma, systemic symptoms, and drug history.
Red flags 🚨: Unilateral obstruction with bleeding, neurological deficits, history of head trauma, or progressive decline without obvious ENT cause.
Examination:
- Anterior rhinoscopy or nasal endoscopy: mucosal inflammation, polyps, obstruction.
- Neurological exam: cranial nerves, memory, Parkinsonian features.

🔍 Investigations

ENT-focused: Nasal endoscopy, CT sinuses (if obstruction, polyps, or chronic sinusitis suspected).
Neurological: MRI brain if associated neurological features or trauma.
Olfactory testing: University of Pennsylvania Smell Identification Test (UPSIT) or simple bedside smell tests (coffee, peppermint).
Blood tests: Consider autoimmune screen, thyroid, and infection markers if systemic disease suspected.

📝 Causes of Anosmia

Cause	Diagnostic Tests	Management	General Advice
Viral Upper Respiratory Infection 🤧	Clinical history of recent cold/flu Nasal endoscopy for inflammation No imaging unless persistent	Symptomatic relief: decongestants, saline irrigation Often resolves spontaneously Short course of steroids if persistent	Rest, hydration Avoid smoke/irritants Hand hygiene to prevent spread
Chronic Rhinosinusitis 🌫️	Nasal endoscopy: mucosal inflammation, polyps CT sinuses Allergy testing if indicated	Intranasal corticosteroids Saline irrigation Surgery (endoscopic sinus surgery) if refractory	Allergen avoidance Maintain nasal hygiene Use humidifiers if dry environment
Nasal Polyps 🍇	Nasal endoscopy (direct visualisation) CT to assess extent	Intranasal steroids ± short oral course Surgical polypectomy if severe/recurrent	Regular follow-up for recurrence Continue sprays to prevent regrowth Avoid smoke/irritants
Head Trauma 🧠	CT/MRI for skull base fracture Neuro exam for other deficits	Observation, rest Olfactory rehabilitation (smell training)	Avoid further head injury Follow up with neurology if persistent
COVID-19 🦠	Clinical diagnosis + PCR	Usually self-resolves Saline irrigation, intranasal steroids if congestion Olfactory training for prolonged anosmia	Self-isolate as per guidelines Regular smell training Monitor for long-COVID symptoms
Neurodegenerative Disorders 🧓	Clinical diagnosis (Parkinson’s, Alzheimer’s) Neuroimaging for brain atrophy Formal olfactory testing	No direct treatment for anosmia Manage underlying disease Olfactory training may help	Neurology follow-up Cognitive/physical therapy
Congenital Anosmia 👶	History since birth Genetic testing in selected cases	No curative treatment Supportive	Educate on safety (smoke/food spoilage) Use alarms/sensors at home

💊 General Management Principles

Treat the underlying cause — infection, allergy, polyps, neurological disease.
Olfactory training: Regular exposure to strong familiar odours (coffee, lemon, rose, eucalyptus) twice daily for ≥12 weeks can improve recovery.
Patient safety: Advise on food spoilage, gas leaks, and smoke alarms.
Multidisciplinary care: ENT, neurology, and sometimes psychiatry (anosmia is linked with depression and reduced quality of life).

✅ Teaching Pearls

Most anosmia is due to ENT pathology, not neurology.
COVID-19 anosmia often recovers spontaneously — but smell training helps in persistent cases.
Unilateral anosmia with obstruction and bleeding = red flag → suspect sinonasal tumour.
Chronic rhinosinusitis and nasal polyps are the most common chronic ENT causes.
Anosmia may precede Parkinson’s disease by years — useful early clue.

💡 Summary: Anosmia is usually benign and ENT-related, but clinicians must be alert for serious causes such as trauma, tumours, and neurodegenerative disease. A systematic approach — history, ENT exam, targeted imaging, and smell training — is essential for safe and effective care.

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Anosmia

📖 Clinical Approach

🔍 Investigations

📝 Causes of Anosmia

💊 General Management Principles

✅ Teaching Pearls

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