Causes of loss of smell

Overview

Loss of smell (also called anosmia) means you cannot smell anything at all, or your sense of smell is much weaker than normal. It can happen suddenly or gradually, and it may affect your ability to taste food too.

Yes, loss of smell is quite common. Many people experience it at least once in their life, often during a cold or sinus infection.

It can affect anyone, but it is more common in older adults, people with allergies or chronic sinusitis, and those who have had a head injury or a viral infection.

Symptoms

Common symptoms

• Complete inability to smell anything
• Reduced ability to smell (hyposmia)
• Difficulty tasting food (taste and smell are linked)
• Noticing that food seems bland or flavourless

Symptoms in children

• Often goes unnoticed because children may not complain about smell loss
• May be seen as picky eating or not noticing strong odours (like burnt toast)
• Can affect their ability to detect danger, like gas leaks or smoke

Symptoms in older adults

• Sudden or gradual loss of smell is common with aging
• May be linked to a lower appetite and weight loss
• Can be an early sign of conditions like Parkinson's or Alzheimer's disease

Causes

Main causes

• Viral infections like the common cold, flu, or COVID-19 (most common)
• Allergies, sinusitis, or nasal polyps (non-cancerous growths in the nose)
• Head injury that damages the nerves for smell
• Aging (presbyosmia) – natural decline in smell sense over time
• Neurological conditions such as Parkinson's disease or Alzheimer's disease
• Certain medicines (temporary side effect)
• Exposure to toxic chemicals or smoke

Risk factors

• Smoking or vaping
• Chronic nasal congestion or sinus infections
• Advanced age (over 60)
• Head trauma (sports, falls, car accidents)
• Family history of smell disorders
• Certain medical conditions like diabetes, hypertension, or thyroid problems

When to see a doctor

See a doctor urgently if:

• If loss of smell happens suddenly with other signs of a stroke (e.g., facial drooping, arm weakness, slurred speech)
• If it follows a serious head injury or you cannot breathe through your nose at all

Book a routine appointment if:

• If loss of smell lasts for more than a few weeks without improving
• If you are concerned it might be a sign of another condition
• If it is affecting your appetite, weight, or quality of life

Diagnosis

Your doctor will ask about your symptoms, when the smell loss started, and any recent illnesses or injuries. They may also look inside your nose with a small light (otoscope) and refer you to an ear, nose, and throat (ENT) specialist if needed.

Tests that may be done

• Smell test – you are asked to identify different scents (like coffee, lemon, or rose)
• Nasal endoscopy – a thin tube with a camera is passed into your nose to look for blockages or polyps
• Imaging scans (CT or MRI) – if your doctor suspects a head injury, sinus problem, or neurological cause

What to expect at your appointment

Most smell tests are quick and painless. If a scan is needed, it is done in a hospital or imaging centre. Your doctor will explain the results and discuss next steps.

Treatment

Treatment depends on the cause. Many cases get better on their own once the underlying condition (like a cold or sinus infection) resolves. If the cause is something like nasal polyps or a head injury, treatment may be different.

Self-care at home

• Practice smell training – smell strong, familiar scents (like lemon, rose, clove, eucalyptus) for 20 seconds twice a day to help retrain your brain
• Keep your nose moist with saline (salt water) sprays or rinses (ask your pharmacist about suitable products)
• Avoid smoking and strong chemical fumes
• Stay hydrated and use a humidifier in dry rooms

Medical treatments

If a sinus infection or allergy is the cause, your doctor may recommend steroid nasal sprays or allergy medications. For nasal polyps, steroid drops or sprays can help shrink them. If a medication is causing the smell loss, your doctor may suggest a different one. No specific drug names or doses are listed here – always follow your healthcare provider's advice.

When is surgery considered?

Sometimes surgery is needed to remove nasal polyps or correct a structural issue in the nose, like a deviated septum. This is usually done by an ENT surgeon after other treatments have not helped.

Living with this condition

Loss of smell can change how you experience food and detect danger. You may need to label food with dates and check smoke alarms regularly. Cooking with strong spices and herbs can help make food more interesting.

Lifestyle tips

• Install smoke and gas detectors in your home and test them monthly
• Check food expiry dates carefully – without smell you might not notice spoiled food
• Consider using a digital thermometer when cooking meat
• Tell friends and family so they can alert you to smells (like burning or gas leaks)

Diet and exercise

Eat a balanced diet with colourful fruits and vegetables to support overall health. If your appetite is low due to bland taste, try adding texture (crunchy foods) and temperature (cold foods) to meals. Gentle exercise like walking can boost mood and general wellbeing.

Mental health and emotional wellbeing

Losing your sense of smell can feel isolating and may affect your mood or appetite. It is normal to feel frustrated or sad. Talk to your doctor or a counsellor if it is bothering you. Many people adapt over time.

Prevention

Not all causes can be prevented, but you can reduce your risk. Protect your head during sports (wear a helmet), avoid smoking, and treat allergies or sinus problems early. Good hand hygiene may help prevent viral infections that affect smell.

Vaccines

Staying up to date with recommended vaccinations (like flu vaccine and COVID-19 vaccines) may lower your risk of viral infections that can cause temporary smell loss.

Screening programmes

There is no routine screening for smell loss. If you notice changes, see your doctor for a check-up.

Complications

If left untreated

• Difficulty detecting danger (smoke, gas leaks, spoiled food)
• Poor appetite and unintended weight loss
• Social isolation or depression due to loss of enjoyment from food and scents

Long-term outlook

Most people with temporary smell loss recover fully over weeks to months. For chronic or permanent cases, many people adapt with time and support. Even when smell does not return, you can still lead a full, safe life. Smell training and safety measures can help.

Find support

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• Your local NHS service · United Kingdom

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