Loss of Smell (Anosmia)

Author: Op. Dr. Javidan Asafov · ENT / Otolaryngology Specialist · Last medical review: 19.10.2026

What is it?

Loss of smell means perceiving smells more weakly than usual (hyposmia) or not being able to smell at all (anosmia). The nerve cells that detect smell are found in a small area in the upper part of the nasal cavity. When odour molecules in the air reach this area, the nerve cells are stimulated and the signal is passed on to the brain.

Smell and taste are closely linked. The tongue detects only basic tastes such as sweet, salty, sour, bitter and umami; the real flavour of food, that is, its aroma, comes from smells that travel from the mouth through the throat to the back of the nose. This is why many people with loss of smell come to the clinic saying “I can’t taste anything”. Loss of smell is common and is usually not a sign of a dangerous disease; however, because it can affect quality of life and everyday safety, it is important to have it assessed.

Symptoms and types

A smell disorder may start suddenly or gradually; it may affect one or both sides, and it may get better and worse from time to time. The main types are:

• Hyposmia: a reduced sense of smell; smells are noticed more weakly or later.
• Anosmia: complete loss of the sense of smell.
• Parosmia: smells are perceived differently from how they really are, usually in an unpleasant way; for example, coffee, onions or meat may smell burnt or rotten. It is often seen during the recovery phase of post-viral loss of smell.
• Phantosmia: sensing a smell that is not present, often a burning or smoky smell.

Loss of smell may be accompanied by enjoying food less than before, a reduced appetite and a wish to add more salt or sugar to food.

Causes

Loss of smell results either from odour molecules being unable to reach the olfactory area (conductive type) or from the olfactory nerves being affected (nerve-related type). Common causes include:

• Nasal blockage and nasal inflammation: chronic sinusitis and nasal polyps are among the common causes of loss of smell. Allergic rhinitis, a bend in the septum, the central wall of the nose (deviated septum), and enlarged turbinates (turbinate hypertrophy) can also contribute by reducing the amount of air that reaches the olfactory area.
• After a viral infection: infections such as colds, flu and COVID-19 can affect the olfactory nerve cells and the cells that support them. If the sense of smell does not return even though the nose has cleared, this points to a post-viral cause.
• Head injury: a blow to the head during a fall or an accident can affect the fine olfactory fibres that run from the nose to the brain.
• Ageing: the sense of smell gradually declines with age and may become noticeable in later life.
• Other causes: smoking, certain chemicals and some medicines are less common causes. A reduced sense of smell can also occur in some neurological diseases such as Parkinson’s disease; however, this is a rare cause. In most people with loss of smell, the cause is nose and sinus disease, a previous infection or age-related decline.

Examination and diagnosis

Assessment starts with a detailed history: you will be asked when and how the loss of smell started, whether you had a cold, flu or COVID-19 beforehand, and about nasal blockage, discharge, allergies, head injury, smoking and the medicines you use. The inside of the nose is then examined endoscopically with a thin camera. This examination shows polyps, signs of sinusitis, enlarged turbinates and a deviated septum.

The extent to which the sense of smell is affected can be measured with smell tests based on recognising different smells; the tests also help to monitor recovery. If needed, a CT scan of the sinuses may be requested when sinusitis or polyps are suspected, and an MRI scan when the loss of smell is unexplained or thought to be nerve-related.

Treatment

Treatment is planned according to the cause. In loss of smell due to nasal blockage and nasal inflammation, treatment can often bring a marked improvement:

• Intranasal corticosteroid sprays or drops: they reduce swelling of the lining caused by sinusitis, polyps and allergy. They are used regularly as recommended by the doctor; holding the head in a suitable position during use can help the medicine reach the olfactory area.
• Rinsing the nose with saline: it clears away secretions and allergens and helps the medicine reach the inside of the nose better.
• Smell training: it involves carefully sniffing a few distinct smells regularly over several months. It can support the recovery of the olfactory system, particularly in loss of smell after a viral infection or a head injury.

Decongestant nasal sprays give short-term relief, but with long-term use they can make blockage worse (nasal spray addiction).

For polyps and chronic sinusitis that persist despite medical treatment, endoscopic sinus surgery can restore airflow to the olfactory area. If a markedly deviated septum or enlarged turbinates restrict airflow, septoplasty or turbinate reduction may also be considered as options.

In loss of smell after a viral infection, the sense of smell returns fully or partly over time in many people; smell training can support this process. Recovery can be slow and requires patience. Parosmia appearing during this period can be distressing, but it is often seen during the recovery process and tends to ease over time.

Safety in daily life

Being unable to smell makes it harder to notice a gas leak, smoke or food that has gone off. A few simple measures make daily life safer:

• Use detectors: keep a gas alarm and a smoke detector at home and check their batteries regularly.
• Pay attention to dates: check the use-by dates on food, write the date on food you have opened or cooked, and do not eat food you are unsure about.
• Take care in the kitchen: do not leave the hob unattended for long while cooking; using a timer helps to prevent food from burning.

When to see a specialist

It is advisable to see an ENT specialist if your sense of smell has noticeably decreased and does not improve after a cold or flu has passed. If loss of smell is accompanied by nasal blockage, discharge or a feeling of fullness in the face, assessment for sinusitis and polyps is needed. Do not put off an examination if your symptoms are on only one side of the nose, if the discharge is often blood-stained, if the loss of smell started after a head injury, or if other new symptoms accompany it.

This article is for general information; please consult your physician for diagnosis and treatment.