Why Am I Losing My Sense of Smell? Common Causes and When to Seek Help

Our sense of smell is easy to take for granted until it changes. A reduced or absent sense of smell can affect the enjoyment of food, our perception of taste and even our ability to recognise potential dangers such as smoke or gas.

Sometimes the cause is temporary and relatively straightforward. In other cases, persistent loss of smell can be associated with an underlying nasal, sinus or olfactory condition that warrants further investigation.

Mr Karan Jolly is a Consultant ENT Surgeon specialising in rhinology and the treatment of nose and sinus conditions, including the assessment of patients experiencing persistent smell disorders.

What is loss of smell?

Changes to the sense of smell can take several different forms.

Anosmia means a complete loss of smell.

Hyposmia describes a reduced ability to smell.

Parosmia occurs when familiar smells become distorted, sometimes causing everyday scents to smell unpleasant or completely different.

Understanding which type of smell disorder you are experiencing, how it started and whether you have other nasal symptoms can provide important clues about the cause.

1. A viral infection

Viral infections are a well-recognised cause of smell loss.

COVID-19 brought widespread attention to this, but other respiratory viruses can also affect the olfactory system.

For many people, smell gradually returns following the infection. For others, recovery can take considerably longer and symptoms such as parosmia may develop during the recovery process.

If smell loss remains persistent, specialist assessment can help rule out other contributing problems and discuss potential treatment options.

2. Chronic rhinosinusitis

Chronic inflammation within the nose and sinuses can interfere with the ability to smell.

Patients with chronic rhinosinusitis may also experience:

• a blocked or congested nose

• facial pressure

• nasal discharge

• recurrent infections

Treating the underlying sinus disease can sometimes improve the sense of smell, although the extent of recovery varies between patients.

3. Nasal polyps

Nasal polyps are benign inflammatory growths that develop inside the nose and sinuses.

As polyps grow, they can prevent odour molecules from reaching the olfactory area high inside the nose. The inflammation associated with polyp disease can also affect smell function.

Treatment may include topical medication, surgery or, in selected patients with severe disease, biologic therapies.

4. Nasal obstruction

Anything significantly restricting airflow through the nose can potentially affect smell.

This may include structural problems or significant swelling within the nasal passages.

A nasal examination and, where appropriate, endoscopy can help determine whether a physical obstruction is contributing to symptoms.

5. Head injury

The nerves responsible for smell travel between the nose and brain through the skull base.

Head trauma can sometimes damage these delicate nerve fibres, resulting in a reduced or absent sense of smell.

The likelihood of recovery depends on the nature and severity of the injury.

6. Age-related changes

Our sense of smell can naturally become less sensitive as we get older.

However, a sudden or substantial change shouldn't automatically be attributed to ageing, particularly where other symptoms are present.

7. Other medical causes

Less commonly, smell changes can be associated with other neurological or medical conditions.

This is one reason why persistent, unexplained or unusual smell loss deserves appropriate assessment rather than simply being ignored.

When should I see a specialist about loss of smell?

Temporary smell loss associated with a cold will often resolve without specialist treatment.

You should consider seeking advice if:

• your smell hasn't returned after a viral illness

• the change has persisted for several months

• you also have chronic nasal blockage or sinus symptoms

• you have nasal polyps

• smells have become persistently distorted

• the loss occurred after a head injury

• there is no obvious explanation for the change

The purpose of assessment is first to establish why the smell loss has occurred before considering treatment.

How is persistent smell loss investigated?

Assessment will usually begin with a detailed history of when the problem started and any associated symptoms.

Depending on the circumstances, further assessment may include:

• examination of the nose

• nasal endoscopy

• assessment for nasal polyps or sinus inflammation

• CT imaging where indicated

• formal smell testing in selected cases

Once the likely cause is established, appropriate treatment options can be discussed.

What treatments are available for loss of smell?

Treatment depends heavily on the cause.

Options may include treating underlying sinus inflammation or nasal polyps, topical nasal medication and smell training, which involves regularly exposing the olfactory system to selected scents.

Karan also offers platelet-rich plasma (PRP) for smell loss in selected patients.

PRP is an emerging treatment being investigated for persistent olfactory dysfunction. It uses platelet-rich plasma derived from the patient's own blood and is delivered to the olfactory region of the nose.

Research into PRP for smell disorders is still developing, so suitability requires careful specialist assessment and results cannot be guaranteed.

Frequently asked questions

Can loss of smell be permanent?

It can be long-lasting in some people, but recovery varies considerably depending on the underlying cause. Some patients continue to experience improvement over an extended period.

Can sinus problems cause loss of smell?

Yes. Chronic sinusitis and nasal polyps are both common causes of reduced smell because of inflammation and obstruction within the nose and sinuses.

Why can I taste food but not smell it properly?

Much of what we perceive as flavour actually comes from smell. A reduced sense of smell can therefore make food seem bland or different even when basic tastes such as sweet and salty remain.

Can anything be done for long-term smell loss?

Potential treatment depends on the cause. Options can include treatment of underlying nasal or sinus disease, smell training and, for selected patients, emerging therapies such as PRP.

What is PRP treatment for smell loss?

PRP uses concentrated platelets taken from a patient's own blood. It is an emerging treatment being investigated for persistent olfactory dysfunction and may be considered for carefully selected patients following specialist assessment.

Specialist assessment for persistent smell loss

If you've noticed a persistent change in your sense of smell, identifying the underlying cause is the first step towards understanding what treatment may be appropriate.

Book a consultation with Mr Karan Jolly for specialist assessment of persistent smell loss and nose or sinus conditions.