Losing your sense of smell

Our sense of smell and the way it operates is incredibly complex. Human brains can identify and process roughly 10,000 different smells using an area the size of a postage stamp. We experience smell by sensing small volatile molecules in the air that reach the six million or so odour receptors in the mucous lining of the nose, high up in the nasal passage.

Smell is powerfully associated with memory. People can remember smells with around 65 percent accuracy a year later, but our visual recall drops to about 50 percent after just three months. Our sense of smell works differently from and has a more direct link to the emotional regions of the brain than the other senses. Although the olfactory stimuli do not reach us at the speed of light or sound, smell is still our quickest sense. With taste, sight and sound, we identify the information first and then only react emotionally. Scents work in the opposite direction, with an emotional reaction followed by an identification of the smell.

Women have a stronger sense of smell than men. And each one of us has a unique odour, a unique olfactory identity similar to a fingerprint. No two people, other than identical twins, smell the same.

Our lives would change significantly if we lost our sense of smell. The deprivation does not end with being unable to enjoy your favourite perfumes or the cherished smells of your loved ones.

Losing your sense of smell affects the enjoyment of food, because around 80 percent of what we experience as taste has something to do with our sense of smell. This is why we experience a diminished sense of taste when we have a cold or flu. Try tasting a mixed packet of jelly beans, savouring flavours one by one in the normal way and then do the same with your nose pinched. You’ll not be able to tell one distinct flavour from another.  Loss of smell can lead to loss of appetite or lack of interest in food, which can cause malnutrition, weight loss and, in some cases, even depression.

Many things can affect our sense of smell. It’s at its weakest in the morning and improves throughout the day. Due to the added moisture in the air, we can smell things better in springtime and during summer. We also feel smells more intensely after exercise because of additional moisture in our nasal cavities.

Losing your sense of smell

Anosmia is the medical term that describes the loss of ability to smell. People can lose their sense of smell completely or partially. Complete loss is rather rare, but it happens. People can suffer from temporary or permanent anosmia depending on what led to the condition.

Anosmia can arise from a host of reasons. The usual causes are irritation or destruction of the mucous membranes that line the inside of the nasal cavity, blocked nasal passages, and brain or nerve damage.

The most common reason is the head cold, which congests nasal passages and irritates the mucous membranes. Sinus infections, hay fever, flu and chronic congestion or sneezing unrelated to allergies are common causes for anosmia.

Obstruction of nasal passages may occur due to nasal polyps, a deviated septum, other bony deformities inside the nose and tumours. Brain or nerve damage anywhere along the olfactory pathway can lead to anosmia. There is a long list of causes that may lead to your losing your sense of smell.

Age, hormonal disturbances, zink deficiency and malnutrition can lead to anosmia. Exposure to certain chemicals such as some types of insecticides or solvents as well as extended exposure to unpleasant smells can lead to loss of smell. Exposure can easily be avoided by wearing a mask.

Brain surgery, rhinoplasty, radiation therapy and certain medications like some medications given for high blood pressure and even cold remedies can lead to a loss of smell. Brain aneurysm, brain tumours and traumatic brain injury can block or destroy your olafactory pathways.

Medical conditions that are associated with the loss of smell include Alzheimer’s disease, diabetes, Huntington’s disease, Kallmann’s syndrome, Klinefelter syndrome, Korsakoff’s psychosis, multiple sclerosis (MS), multiple system atrophy (MSA), Paget’s disease of bone, Parkinson’s disease, Pick’s disease, Schizophrenia and Sjogren’s syndrome.

Treating anosmia

Treatments for anosmia depend on its causes. Irritation or congestion caused by a cold, flu, allergies or sinus infections usually clear up on their own. If not you may want to see a doctor and obtain necessary treatment. Antibiotics, nasal steroid spray or allergy treatments may help. However, chronic use of over the counter nasal decongestant sprays can also wipe out your sense of smell, sometimes permanently.

Severe blockages due to a deviated septum or overgrown bony structures (nasal turbinates) may need to be treated with functional rhinoplasty.

You can read about the experience of one of my patients, Stephanie Darling, in an article published in Madison magazine.

For more information

If you wish to find out more information on how nose surgery can treat anosmia (loss of smell), or wish to make an appointment with Dr Marcells, please contact us on 1300 555 095. You can also use email or the ‘book consultation’ feature of this website to make an appointment.

Please share this info

If you found this information on our sense of smell useful, please share it with your network on Facebook.