More than just a scent: The hidden struggles of smell disorders

Would you sacrifice your sense of smell to keep your hair? Or perhaps your phone?

A 2022 study from the US explored how people value their sense of smell in comparison to other senses like sight and hearing, as well as personal belongings such as money, pets and hair. The results showed that smell was considered far less important than sight and hearing, and was valued less than many material things.

For example, half the women surveyed said they would rather hold on to their hair than their sense of smell. This devaluation of smell stems from a lack of understanding about its vital role in our everyday lives, influencing our memories, emotions, safety and overall well-being. Yet, when we dig deeper into the impact of this sense, it becomes clear just how integral it is to our overall quality of life.

Dr Peter Ochung’o, a Consultant Ear, Nose and Throat (ENT) and Neck Specialist, explains that the ability to smell is more than just a pleasant experience; it’s crucial for our safety and emotional well-being. “Smell disorders do not just rob individuals of the pleasure of enjoying food or flowers; they also compromise personal safety by impairing the ability to detect hazards such as smoke, gas leaks, or spoiled food,” he says.

The loss of smell also affects emotional well-being, as scent is closely tied to memory and personal experiences. “Many people don’t realise how much their sense of smell contributes to their daily lives until they lose it. It is one of those senses that works silently in the background but is critical to our survival and enjoyment,” Dr Ochung’o adds.

“Our sense of smell is part of the chemical senses,” explains Dr Ochung’o. Specialised sensory cells, called olfactory sensory neurons, are located in a small patch of tissue deep inside the nose, known as the olfactory epithelium. These cells connect directly to the brain.

Each olfactory neuron expresses one odour receptor. When molecules from food or other substances are released, they stimulate these receptors. Once the neurons identify the specific molecule, they send a message to the brain, which then recognises the smell.

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Causes

Smell disorders can arise due to various reasons. Viral infections such as flu, Covid-19 and sinus infections can damage olfactory neurons, leading to temporary or permanent smell dysfunction. “Up to 7 per cent of individuals who had smell disorders from Covid-19 continue to have the same. Extending beyond 12 months post onset of the disease,” says Dr Ochung’o.

“Nasal obstructions caused by polyps, chronic sinusitis or structural abnormalities in the nasal cavity can prevent odours from reaching the olfactory epithelium,” explains Dr Ochung’o. “Head trauma, particularly injuries affecting the orbitofrontal cortex, can disrupt the olfactory pathways.”

Neurological diseases like Parkinson’s and Alzheimer’s often present with early signs of smell loss before cognitive decline. Exposure to toxic substances, including industrial chemicals, pesticides or solvents, may also impair olfactory function. Certain medications, including antibiotics, chemotherapy agents and antidepressants, have been reported to alter smell perception. The growing use of air pollutants and exposure to synthetic chemicals may contribute to an increasing prevalence of olfactory dysfunction worldwide.

Did you know that your ability to smell can be influenced by both age and gender? Dr Ochung’o notes that women generally have a better sense of smell than men, though the exact reasons are still unclear. It could be linked to hormonal differences or perhaps women’s higher social awareness.

“As we age, our sense of smell tends to decline, largely due to a reduction in olfactory receptor neurons. Interestingly, factors like being female, young, a non-smoker and having no noticeable differences in smell function between the left and right sides of the nose can all contribute to better recovery from smell disorders caused by infection or trauma.

The symptoms of smell disorders vary depending on the type and severity of the condition. Individuals may experience a complete inability to detect odours, a reduced sensitivity to certain scents, a distorted perception of familiar smells or the sensation of non-existent odours. In some cases, the condition is accompanied by a loss of taste perception, as smell contributes significantly to flavour recognition.

Many individuals with smell disorders report a decreased appetite, unintended weight loss and social withdrawal due to an impaired ability to enjoy meals or detect body odours. Studies show that people with anosmia or hyposmia often suffer from depression, anxiety and reduced social engagement, as they lose an important sensory link to their environment.

Beyond the sensory aspect, the inability to smell affects daily life in profound ways. Individuals with anosmia are at higher risk of food poisoning, as they cannot detect spoiled food. They are also more vulnerable to household hazards, unable to notice gas leaks or fires. Additionally, loss of smell influences appetite and weight, as flavour perception heavily relies on olfaction.

From a psychological perspective, anosmia has been linked to depression and reduced quality of life. “We often take our sense of smell for granted, but its absence can make life feel dull and disconnected,” Dr Ochung’o points out. “For some patients, the loss of smell means losing treasured memories associated with certain scents, making it a deeply personal and emotional struggle.”

Diagnosis and treatment

Various tests assess olfactory function, including the University of Pennsylvania Smell Identification Test and Sniffin’ Sticks, which require patients to identify specific odours. Advanced diagnostic tools such as electrophysiological assessments and MRI scans may also be used to detect abnormalities in the olfactory bulb or neural pathways.

Treatment depends on the cause and severity of the condition. Medications such as corticosteroids help treat inflammation-related anosmia or hyposmia, especially in sinus infections. Surgical procedures to remove nasal polyps or correct structural abnormalities can restore airflow and improve smell perception.

Smell training, a therapy involving repeated exposure to strong scents such as lemon, rose, clove and eucalyptus, has been shown to help retrain the brain’s olfactory pathways.

While not all smell disorders are preventable, certain measures can help reduce the risk. Avoiding smoking and exposure to airborne toxins can preserve olfactory function. Maintaining good nasal hygiene can help prevent infections that might impair smell perception. Using protective gear in environments with strong chemicals can minimise damage to the olfactory system.

Seeking prompt medical attention for respiratory illnesses and following a healthy diet to prevent vitamin and mineral deficiencies are also essential in protecting the sense of smell.

Would you still trade your sense of smell for something else? Perhaps now you’re not so sure.