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Health condition

Loss of smell, from post-viral anosmia to when it signals something more.

Most smell loss follows a cold, flu or COVID-19 and improves with time and training. A minority of cases need imaging and specialist referral - knowing which is which matters.

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Why trust this guide

  • 01

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

    Checked against ENT UK, the British Rhinological Society and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK guidance including olfactory training, red-flag imaging and smell-clinic pathways.

Key facts

Loss of smell at a glance.

The essentials, in plain English - what it is, why it happens, and how it’s assessed in the UK today.

  • What it is

    Anosmia is complete loss of smell and hyposmia is reduced smell - both affect taste, appetite and safety.

  • Leading cause

    Post-viral loss, especially after COVID-19, is now the most recognised trigger in adults - see our coronavirus guide.

  • Sinonasal cause

    Chronic rhinosinusitis, nasal polyps and allergic rhinitis cause conductive smell loss - often reversible with treatment.

  • Distorted smell

    Parosmia (distorted smells) and phantosmia (phantom smells) commonly appear during post-viral recovery.

  • Neurological clue

    Smell loss can precede Parkinson’s and dementia by years - it is one reason unexplained cases need careful assessment.

  • Main treatment

    Structured olfactory training with four distinct scents, twice daily for months, has the best evidence for post-viral loss.

Why this guide matters

Common, often overlooked - occasionally significant.

Loss of smell rarely gets the attention it deserves, yet it affects safety, nutrition and mood - and, rarely, points to something that needs early treatment. The three points below shape everything else on this page.

  • Post-viral loss is now common

    COVID-19 pushed smell loss into everyday conversation - most cases follow a viral illness and improve with time and training.

  • Sinonasal causes are often treatable

    Nasal polyps, chronic rhinosinusitis and allergic rhinitis frequently respond well to intranasal steroids and, if needed, surgery.

  • A minority need urgent imaging

    Unilateral or progressive loss with headache or neurological signs is uncommon but important to catch early.

How the diagnosis is made

From first assessment to a clear plan.

The steps a UK GP or ENT specialist will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    Detailed history

    Onset - sudden or gradual - plus any preceding cold, flu or COVID-19, head injury, or new medication.

  2. 02

    Assessing

    Screen for red flags

    Unilateral loss, a progressive course, headache or any neurological symptom changes the assessment path.

  3. 03

    Assessing

    Nasal endoscopy

    A flexible nasoendoscopy looks for polyps, inflammation or obstruction along the nasal passages and olfactory cleft.

  4. 04

    Confirming

    Formal smell testing

    Validated tools such as Sniffin’ Sticks or the UPSIT quantify the degree of loss in a specialist smell clinic.

  5. 05

    Confirming

    Specialist ENT referral

    Persistent, atypical or red-flag presentations are referred on for a dedicated smell and taste assessment.

  6. 06

    Excluding

    MRI brain if red flags

    Unilateral, progressive loss or neurological signs warrant MRI to exclude a tumour such as meningioma - specialist commissioned.

  7. 07

    Excluding

    Neurology input if atypical

    Where a neurodegenerative cause is suspected, joint ENT and neurology review looks at the wider clinical picture.

Typical timeline: a first visit to a settled plan within a few weeks, faster if red flags are present.

Symptoms

What smell loss actually feels like.

From simple reduced smell to distorted and phantom smells. And the features that mean it’s time to seek urgent review.

  • Anosmia

    Complete loss of smell - food tastes flat, and everyday cooking, hygiene and safety cues are affected.

  • Hyposmia

    Reduced but not absent smell - often the pattern in ageing, allergic rhinitis and early sinonasal disease.

  • Parosmia

    Familiar smells - coffee, meat, onions - are distorted into something unpleasant, usually during post-viral recovery.

  • Phantosmia

    Smelling something that isn’t there - a phantom odour, often smoky or burnt, with a genuine quality-of-life impact.

  • Blocked, congested nose

    A sensation of nasal fullness alongside smell loss points towards a sinonasal or allergic cause.

  • Reduced taste

    Because flavour depends heavily on smell, many people describe this as losing their sense of taste too.

  • Gradual, age-related decline

    Presbyosmia - a slow decline in smell with age - is common and usually not a cause for alarm on its own.

  • Red flag - unilateral or progressive

    One-sided, worsening loss, headache or neurological signs need prompt specialist assessment to exclude a tumour.

Treatment

How loss of smell is treated in the UK.

Olfactory training and treating any underlying sinonasal cause come first - with selective surgery and psychological support where they help.

  • Olfactory training

    Structured smell training with four distinct scents, twice daily for several months - the best-evidenced option for post-viral loss.

  • Intranasal corticosteroids

    Reduces inflammation from allergic rhinitis, chronic rhinosinusitis or nasal polyps - often paired with saline irrigation.

  • Saline nasal irrigation

    Simple, low-risk washout that clears mucus and supports the nasal lining alongside other treatments.

  • Treating allergic rhinitis

    Antihistamines and allergen avoidance calm hay fever-driven nasal swelling that can block the smell pathway.

  • Selective nasal polypectomy

    Surgical removal of obstructing polyps when medical treatment hasn’t restored an open nasal airway - specialist ENT.

  • Short-course oral corticosteroids

    Used selectively for inflammatory causes not settling with topical treatment alone - under specialist guidance.

  • Parosmia management

    Avoiding known trigger foods while continuing olfactory training - specialist smell-clinic support helps pace recovery.

  • Vitamin A nasal drops

    Selective evidence in some post-viral and post-traumatic cases - discussed and monitored with a specialist.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or ENT specialist knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • ENT UK. Guidance on the management of anosmia.

  • British Rhinological Society (BRS). Smell and taste disorder pathways.

  • Fifth Sense. Patient information and support for smell and taste disorders.

  • Royal College of Surgeons of England. Loss of sense of smell as a marker of COVID-19.

Red flags

When loss of smell needs urgent attention.

Most smell loss is manageable in primary care. These are the situations that aren’t - and where a specialist opinion is needed.

  • Unilateral smell loss

    One-sided loss is not typical of common viral or allergic causes and warrants prompt specialist assessment.

  • Progressive worsening

    Smell loss that keeps deteriorating over weeks or months, rather than stabilising, needs imaging to exclude a growing lesion.

  • Associated headache

    New or worsening headache alongside smell loss is a recognised pointer towards an olfactory groove meningioma.

  • Neurological signs

    Visual change, weakness, personality change or seizures alongside smell loss need urgent neurological assessment.

  • Nasal bleeding or a visible mass

    Blood-stained discharge or a lump seen on endoscopy raises concern for a tumour such as esthesioneuroblastoma.

  • Head trauma with sudden loss

    Sudden anosmia after a head injury suggests shearing of the olfactory nerves at the cribriform plate - worth documenting and reviewing.

  • Early motor or cognitive symptoms

    New tremor, stiffness, memory changes or confusion alongside long-standing smell loss should prompt a wider neurological review.

  • Safety incidents

    Missing a gas leak, smoke, or spoiled food because of smell loss is a genuine safety issue worth raising with your GP.

  • Congenital absence with reduced puberty

    Anosmia present from birth alongside delayed puberty can suggest Kallmann syndrome and needs endocrine assessment.

Living with it

Often improves, with patience and practice.

Four things that make the biggest difference day to day - consistent smell training, practical safety steps, adapting how you eat, and knowing support exists.

A quiet reminder

Recovery is often measured in months, not days.

Steady, patient effort with smell training gives the best chance of meaningful improvement over time.

  1. 01 Train

    Stick with smell training

    Rose, lemon, clove and eucalyptus, twice daily, for months - consistency matters more than intensity.

  2. 02 Safety

    Build in safety checks

    Fit smoke and carbon monoxide alarms, and set reminders to check food dates since spoilage may go unnoticed.

  3. 03 Eating

    Adapt how you eat

    Texture, temperature and spice can bring back some enjoyment of food when flavour is muted.

  4. 04 Support

    You’re not alone with this

    Charities such as Fifth Sense offer peer support - the quality-of-life impact of smell loss is real and worth talking about.

Frequently asked

Everything we get asked about loss of smell.

Quick answers on post-viral loss, parosmia, olfactory training and when imaging is needed.

  • What is the difference between anosmia and hyposmia?

    Anosmia is a complete loss of the sense of smell, while hyposmia is a partial or reduced sense of smell. Both can affect taste, appetite and safety, and the underlying causes overlap considerably.

  • Will my smell come back after COVID-19?

    Many people recover over weeks to months as the olfactory neurons regenerate, though some experience persistent loss or parosmia. Olfactory training, started early, gives the best chance of meaningful recovery.

  • What is parosmia and why does it happen?

    Parosmia is a distortion of smell, where familiar odours - coffee, meat, onions - become unpleasant or unrecognisable. It typically appears during the recovery phase after a viral illness, as regenerating nerve connections briefly miswire.

  • Can loss of smell be a sign of something serious?

    Usually it follows a viral illness or sinonasal condition, but unilateral, progressive loss, headache or neurological symptoms can point towards a tumour or a neurodegenerative condition, and deserve prompt specialist review.

  • How does olfactory training actually work?

    You sniff four distinct scents - typically rose, lemon, clove and eucalyptus - for around 20 seconds each, twice a day, for several months. It is thought to encourage regeneration and rewiring of olfactory pathways, and has good supporting evidence for post-viral loss.

  • When would I need an MRI scan for smell loss?

    An MRI brain is used when there are red flags - unilateral or progressive loss, headache, or other neurological signs - to exclude a tumour such as an olfactory groove meningioma. It isn’t routinely needed for typical post-viral or sinonasal smell loss.

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