Loss of smell (anosmia)

Common causes include viral infections such as colds or COVID-19, chronic sinus conditions, nasal polyps, ageing, head injury, and certain neurological conditions. Sometimes no clear cause is identified despite thorough investigation.

In most cases it's not dangerous itself, but it can affect quality of life, including enjoyment of food and safety awareness around things like gas leaks or spoiled food, and, rarely, it can be an early sign of certain neurological conditions. Persistent unexplained loss of smell is worth investigating.

Alongside reduced or absent smell, many people notice a corresponding reduction in taste, since the two senses are closely linked, and food may seem bland or less enjoyable. Some people also experience distorted smells (parosmia) as smell function recovers from certain causes, such as viral infection.

Some rare causes of loss of smell, such as certain inherited conditions like Kallmann syndrome, do have a genetic basis, but the vast majority of cases, related to infection, sinus disease or ageing, aren't directly inherited. A detailed history helps clarify the likely cause in your specific case.

This depends on the cause: smell loss from sinus conditions or nasal polyps can often improve with appropriate treatment, and post-viral smell loss frequently improves over time, sometimes helped by specific smell training exercises. Loss related to ageing or certain neurological conditions is generally less likely to fully recover.

Treatment targets the underlying cause where possible, such as treating chronic sinusitis or removing nasal polyps, alongside smell training exercises which can help some people, particularly after viral infections, gradually recover function. Your ENT specialist will advise on the most appropriate approach for your specific cause.

Investigation typically involves examination of the nose and sinuses, sometimes with nasal endoscopy, and imaging such as a CT scan if a structural cause is suspected. Specific smell testing can also help quantify the degree of loss and track any recovery.

This varies considerably; some people recover within weeks, while others take many months, and a proportion experience more prolonged or incomplete recovery. Smell training exercises, done consistently over months, can improve the chances and speed of recovery for many people.

Loss of smell from sinus disease or nasal polyps is often accompanied by nasal blockage or other sinus symptoms and can improve significantly once the underlying nasal issue is treated, while loss from nerve damage (such as after significant head injury or viral infection affecting the smell nerve directly) is less likely to improve simply by treating the nose. ENT assessment, sometimes with imaging, helps distinguish between these different mechanisms.

Persistent, unexplained loss of smell, particularly without an obvious cause like a recent cold, should be assessed by an ENT specialist. Private ENT consultations can typically be arranged within about two weeks, considerably faster than standard NHS waiting times.