Losing your sense of smell

Written by: Professor Carl Philpott
Published: | Updated: 09/07/2021
Edited by: Kalum Alleyne

Most of us take our sense of smell for granted and we usually only realise its importance once it's gone. Leading ENT surgeon Professor Carl Philpott highlights some of the main causes of losing this sense.


A woman smelling some flowers


What are the most common causes of loss of smell?

There are many possible causes of loss of smell, which range from minor problems like the common cold or hay fever to obstructions caused by abnormalities like tumours, nasal polyps and a deviated septum. Research also indicates that it can also be linked to serious neurological conditions like Alzheimer’s, Parkinson’s disease, and multiple sclerosis. For many years such links have been largely ignored, but now scientists are championing their use as diagnosis-aiding tools.


Can loss of smell be a symptom of serious conditions?

Studies show that the pathology of neurological diseases, such as Parkinson’s, begin in the nose, happens long before signs are visible anywhere else. There are numerous examples of patients losing their sense of smell years before they are diagnosed with a serious neurological condition. The statistics also support this theory; 38 per cent of people with multiple sclerosis and between 45 and 96 per cent of people with Parkinson’s disease show signs of loss of smell five years prior to diagnosis. As a result, smell tests are now being used to detect such conditions earlier than ever before.


Neurological conditions are not the only cause of smell impairment, it is believed that one in five people have some sort of problem with their sense of smell, with 0.3 per cent reporting a complete loss. Recent research shows that smell loss may also be connected to mental health disorders like depression and schizophrenia. A 2016 study showed that men suffering from depression were more likely to have problems with their sense of smell, while those experiencing loneliness found it more difficult to identify different scents. In a separate study of over 2,000 people between the ages of 71 and 82 with an impaired sense of smell, it was discovered that they had an almost 50 per cent higher chance of dying within 10 years, than those with no smell problems.


Is diet linked to sense of smell?

Your health is undeniably linked to your diet. After analysing the dietary habits of patients with smell loss, it was found that a third of them were overeating, while a third of them were undereating. Our sense of smell can account for up to 70 per cent of the flavours we taste, which explains why it’s harder to taste food when you have a blocked nose and why losing it can result in loss of appetite. Losing previously felt enjoyment in activities like eating is a key factor in the onset of depression, so it is vitally important to do all we can to maintain our sense of smell.


How can losing your sense of smell affect your life expectancy?

Another possible reason for the link between sense of smell and life expectancy is that smell impairments can lead to greater exposure to dangerous situations. For example, if you’re walking down the street and you smell car fumes, you’d automatically cross the road or speed up. Someone with an impaired sense of smell would not notice the smell, which would lead to them inhaling more of the toxic fumes.


Can your sense of smell ever come back?

It is also believed that, as well as the parts of the brain involved in recognising smell, parts important for motor control, processing emotions and rational thinking, like the cingulate cortex, may shrink as a result of loss of smell. The good news is that these parts can grow back as a person regains their sense of smell and there are plenty of methods being invented to aid this.


Thomas Hummel of the Smell and Taste Clinic at the University of Dresden, has created something called 'smell training’. It is a test which consists of patients smelling a scent that combines smells from four different odour categories for 10 minutes, two times a day, for three months. This method has proven effective on 40 per cent of patients.


Other techniques being developed include stimulating regions of the brain associated with smell and a portable device that can be put on when needed, similarly to glasses.


So, if you’re experiencing problems with your smell, it’s important to have it looked at by a specialist. Help is available. Professor Carl Philpott is a leading ENT specialist in Norwich and Great Yarmouth. You can request an appointment with him by visiting his profile.

By Professor Carl Philpott
Otolaryngology / ENT

Professor Carl Philpott is a leading ear, nose and throat specialist in Norwich and Great Yarmouth whose areas of expertise in rhinology includes sinusitis, smell and taste disorders, allergic fungal rhinosinusitis and endoscopic sinus surgery.

Professor Philpott is a graduate of Leicester University Medical School. He completed his basic surgical training in the University Hospitals of Leicester before undertaking a period of research (2003-4) into developing apparatus for testing the sense of smell, which culminated into his MD thesis.

Professor Philpott’s specialist training was completed in East Anglia and during this time he spent a year at the St Paul’s Sinus Centre in Vancouver, Canada. Here he learnt advanced skills in endoscopic sinus surgery for inflammatory disease of the nose and sinuses as well as tumours of the sinuses and anterior skull base.

He also spent time at the Dresden University Smell and Taste Clinic learning techniques for assessing and researching the sense of smell. Professor Philpott is the Director of the first British Smell and Taste Clinic, established in 2010, where he receives referrals from around the UK.

Professor Philpott is an academic surgeon at the University of East Anglia where he leads the Rhinology & ENT Research Group with a number of research projects, including a major national trial for patients with chronic sinusitis. He is President of the British Otorhinolaryngology & Allied Sciences Research Society and the Eastern Clinical Research Network Lead for ENT. He is a regular reviewer for various specialty journals as well as being Associate Editor for Clinical Otolaryngology and an Editorial Board member for Rhinology Journal. He has published over 140 journal articles in his field of practice as well as authoring various book chapters and is co-editor of Bullet Points in ENT.

He is involved in both undergraduate and postgraduate education at the University of East Anglia and beyond. At Norwich Medical School he is the Professionalism Lead and a member of the module team that covers the teaching of Otorhinolaryngology. He teaches on a number of external courses including ones in London, Guildford, Newcastle, Dresden and Vancouver.

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