Nose
Loss of smell
A reduced or absent sense of smell — often dulling the sense of taste as well — which is most commonly caused by a blocked or inflamed nose after a viral infection or allergy, but occasionally points to a nerve or brain problem that needs urgent attention.
Education and reference only. This explains the common causes of loss of smell and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is loss of smell?
Smell depends on tiny nerve endings high inside the nose detecting airborne molecules and sending signals to the brain. Anything that blocks air reaching them, or that damages the nerves or their pathways, can dull or remove the sense of smell — and because flavour relies heavily on smell, food often tastes bland at the same time.
- Get urgent help: Call 999 or go to A&E for a sudden total loss of smell after a head injury, especially with confusion, vomiting or drowsiness. Call 999 if loss of smell comes with new weakness, numbness, slurred speech or facial droop — these are signs of a stroke.
- Self-care: When loss of smell follows a cold, flu or other viral illness, it usually improves as the nose clears, so gentle measures that ease congestion help: stay hydrated, inhale warm, moist air and use saline rinses to soothe and unblock the nasal lining.
About loss of smell
Smell depends on tiny nerve endings high inside the nose detecting airborne molecules and sending signals to the brain. Anything that blocks air reaching them, or that damages the nerves or their pathways, can dull or remove the sense of smell — and because flavour relies heavily on smell, food often tastes bland at the same time. The commonest causes are entirely benign: a heavy cold, flu, COVID-19 or chronic nasal inflammation swells the lining so odours cannot reach the smell receptors, and the sense usually returns as the nose clears, though after some viral infections recovery can take weeks or months. A more gradual, lasting decline can accompany certain long-term neurological conditions. The pattern that matters most is a sudden, complete loss after a head injury, or one paired with new weakness, confusion or other nervous-system signs, which needs prompt assessment.
When to get help
Call 999 or go to A&E if loss of smell comes with any of these warning signs:
- Call 999 or go to A&E for a sudden total loss of smell after a head injury, especially with confusion, vomiting or drowsiness.
- Call 999 if loss of smell comes with new weakness, numbness, slurred speech or facial droop — these are signs of a stroke.
- Seek urgent help if loss of smell appears with a severe headache, a stiff neck, fever and dislike of light.
- See your doctor promptly if smell is lost on one side only or with persistent one-sided nasal blockage or bleeding.
- See your doctor if loss of smell is gradual, lasting and unexplained, particularly with changes in memory, movement or balance.
When to see a doctor
A reduced sense of smell during or just after a cold, flu or COVID-19 is common and usually recovers, so it does not normally need a doctor unless it lasts beyond a few weeks. Treat sudden, complete loss of smell after a head injury as urgent, and seek emergency help if it comes with weakness, confusion, slurred speech or a facial droop. Book a routine appointment for smell that is slow to return, that is fading gradually and unexplained, or that comes with a persistently blocked or bleeding nose on one side, so the cause can be examined directly.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of loss of smell
Loss of smell has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
When loss of smell follows a cold, flu or other viral illness, it usually improves as the nose clears, so gentle measures that ease congestion help: stay hydrated, inhale warm, moist air and use saline rinses to soothe and unblock the nasal lining. If an allergy is the trigger, reducing exposure to the cause often restores smell. Smell training — calmly sniffing a small set of familiar, strong scents such as coffee, citrus, herbs and flowers twice a day over several weeks — is a safe, evidence-informed way to help the sense recover after a viral infection. While your sense of smell is reduced, take care with gas safety and check food dates carefully, since you may not detect a gas leak or spoiled food.
Answers
Loss of smell: frequently asked questions
Will my sense of smell come back after a virus?
Usually yes. Smell often returns within a couple of weeks as the nose clears, though after some viral infections it can take several months. Smell training with familiar strong scents can help. If it has not improved after a few weeks, see your doctor.
Why does food taste bland when I lose my smell?
Most of what we experience as flavour actually comes from smell, not the tongue. When the sense of smell is blocked or damaged, food tastes flat even though basic tastes like sweet and salty may still work, so the two often go together.
When is loss of smell an emergency?
Seek emergency help if smell is lost suddenly and completely after a head injury, or if it comes with new weakness, numbness, slurred speech, facial droop or confusion. These can signal a brain injury or stroke rather than a nose problem.
Can losing my sense of smell be dangerous in daily life?
It can, because you may not detect a gas leak, smoke or food that has gone off. While your smell is reduced, fit working smoke and gas alarms, take care around cooking and gas appliances, and check food dates rather than relying on smell.
Sources
Where this is drawn from
- NICE CKS: Smell and taste disturbance.
- Fifth Sense (smell and taste disorders charity).
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