Smell identification test

Overview

A smell identification test is a simple, non-invasive test that checks how well you can detect and recognise different smells. It is often used to help diagnose conditions that affect your sense of smell, such as anosmia (complete loss of smell) or hyposmia (reduced sense of smell).

Smell problems are fairly common, affecting about 1 in 5 people at some point. Smell identification tests are a routine way to measure smell loss.

The test is used for people of all ages who have noticed changes in their sense of smell, especially older adults, those with head injuries, or those with possible early signs of conditions like Parkinson's disease or Alzheimer's disease.

Symptoms

Common symptoms

• Noticing that food doesn't taste the same (taste and smell are closely linked)
• Difficulty smelling familiar scents like flowers, food, or smoke
• Complete loss of smell (anosmia)

Symptoms in children

• Picky eating or avoidance of certain foods because they don't taste right
• Not reacting to strong smells that would normally bother them (like a dirty nappy or rotten food)
• Trouble smelling smoke or gas – which can be a safety concern

Symptoms in older adults

• A gradual or sudden decrease in the ability to smell
• Noticing food is bland or tasteless
• Changes in smell that may be an early sign of a neurological condition

Causes

Main causes

• Blockages in the nose, like from allergies, a cold, or sinus infection
• Damage to the olfactory nerves (the nerves that carry smell signals to the brain) from a head injury or virus (like COVID-19)
• Aging – our sense of smell naturally declines as we get older

Risk factors

• Having a condition like Parkinson's disease, Alzheimer's disease, or multiple sclerosis
• Smoking cigarettes
• Exposure to chemicals or toxins in certain jobs (like painting or cleaning)
• Previous nasal surgery or polyps

When to see a doctor

See a doctor urgently if:

• Sudden loss of smell after a head injury
• Loss of smell along with other stroke symptoms (like weakness on one side of the body)
• Loss of smell with a severe headache or neck stiffness

Book a routine appointment if:

• Your sense of smell is not improving after a cold or sinus infection has cleared
• You have had a gradual loss of smell for weeks or months with no obvious cause
• You are concerned about early signs of a memory or movement disorder

Diagnosis

A smell identification test is usually performed by a doctor, an ear, nose and throat specialist (ENT), or sometimes a neurologist. You will be asked to scratch and sniff a set of small cards or bottles with different scents and then choose the correct smell from a list of options.

Tests that may be done

• Scratch-and-sniff test cards (like the University of Pennsylvania Smell Identification Test or UPSIT)
• Simple bedside test using common household items (like coffee grounds, lemon, or rose soap)
• An exam of your nose with a small camera (nasal endoscopy) if the doctor suspects a blockage

What to expect at your appointment

The test takes about 10 to 20 minutes. You will be asked to close your eyes or not look at the labels. There are no needles or pain. After the test, your doctor will compare your results with normal values for your age and sex. They will then discuss what the results mean for you.

Treatment

Treatment depends on the cause of your smell loss. If the cause is a temporary blockage (like a cold), your sense of smell may come back on its own. For other causes, your doctor will treat the underlying condition.

Self-care at home

• Practice 'smell training' – sniffing strong, familiar scents twice a day to help retrain your nose
• Keep your nose moist with saline sprays if you have stuffiness
• Avoid smoking and second-hand smoke

Medical treatments

Your doctor might prescribe nose sprays or other medications to reduce swelling inside your nose. They may also treat any underlying infections or allergies. For smell loss due to neurological conditions, treatment focuses on managing that condition. Always follow your doctor's advice.

When is surgery considered?

If a blockage like a nasal polyp or tumour is causing your smell loss, your doctor may recommend surgery to remove it. This is not common.

Living with this condition

Living with a reduced sense of smell can change how you enjoy food and can be a safety concern. It's important to put extra thought into kitchen safety (like using smoke detectors) and checking food expiration dates.

Lifestyle tips

• Install smoke alarms and check them regularly
• Mark food with dates so you don't eat spoiled items
• Use a gas detector if you have a gas stove or heater

Diet and exercise

You may need to add more spices and textures to your meals to make food interesting. A healthy diet with plenty of fruits and vegetables supports overall health. Exercise is good for your general wellbeing and may help with conditions that affect smell.

Mental health and emotional wellbeing

Losing your sense of smell can be upsetting and feel isolating. It's normal to feel frustrated or sad. Talk to your doctor if it affects your mood or appetite.

Prevention

Not all smell loss can be prevented, but you can reduce your risk by avoiding head injuries (use seat belts and helmets) and by avoiding smoking. If you work with strong chemicals, use proper protective gear.

Vaccines

Some infections that damage smell (like COVID-19) may be prevented with vaccination. Talk to your healthcare provider about recommended vaccines.

Screening programmes

Routine screening for smell loss is not usually done, but if you are at higher risk (e.g., you have a family history of Parkinson's disease), your doctor may recommend a baseline test.

Complications

If left untreated

• Decreased ability to detect dangerous smells like gas leaks or smoke
• Weight loss or poor nutrition from loss of appetite
• Reduced quality of life and possible social withdrawal

Long-term outlook

For many people, a sense of smell gradually returns on its own or with treatment. If the loss is due to a permanent condition, there are ways to adapt and cope. Often, with patience and the right support, people can live fully and safely.

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