Aromas Amplified: Sickness And The Power Of Smell

The human olfactory system is an incredibly powerful tool that can influence our emotional and physical state. The sense of smell is the only sense with a direct link to the brain. When we inhale aromas, they are chemically converted and passed to our brain, triggering the release of neurochemicals and subsequent effects.

For some people, certain aromas can be too strong, causing a range of adverse reactions. This condition is known as hyperosmia, where individuals experience a heightened sense of smell. It is believed that this is caused by a misfiring or disequilibrium in the nerves that process smell.

People with hyperosmia can experience a range of symptoms when exposed to strong fragrances, including headaches, respiratory problems, anxiety, and nausea. These symptoms can be disruptive to everyday life, causing some individuals to avoid certain places or situations.

The trigeminal nerve, which lines the nasal cavity, plays a crucial role in scent sensitivity. This nerve sends sensory information to the brain, and in people with hyperosmia, certain scents can irritate this nerve, triggering unpleasant symptoms.

While the specific causes of scent sensitivity are not fully understood, certain factors such as asthma, allergies, migraines, hormonal fluctuations, and endocrine, metabolic, or autoimmune disorders can increase the likelihood of experiencing scent sensitivities.

For those who struggle with strong aromas, there are strategies to find relief. Avoiding known triggers, counter-stimulation techniques using scents like peppermint, and medical treatments such as steroids, antihistamines, nerve-blocking injections, or ablations can help manage the condition.

Fragrances can cause health issues

Fragrances can cause a range of adverse health effects, and some people are more susceptible to these effects than others. In a study of 1,098 Australians, one-third of participants reported experiencing health issues due to scented products. Similarly, in the US, 35% of people experience health issues from fragrances, according to a study by Anne Steinemann, Ph.D.

The health issues caused by fragrances can range from mild annoyances to severe and disabling problems. Some of the most commonly reported issues include respiratory difficulties, migraines, eye irritation, sneezing, dizziness, headaches, nausea, and mental cloudiness. These issues can be severe enough to cause people to miss work, and in some cases, even lose their jobs.

The specific chemicals in fragrances that cause these issues are often not disclosed to the public. However, we know that many fragrances contain volatile organic compounds (VOCs) which can irritate and disrupt our airways and have other negative health effects. When we breathe in fragrances, the particles are small enough to enter our bloodstream.

People who work in industries such as cleaning, cosmetics, or agriculture, where they are continuously exposed to fragrances, are at the highest risk of adverse health effects. However, anyone can be impacted by fragrances, even those without underlying chronic lung diseases. For example, many people have experienced coughing or sneezing when walking through the fragrance section of a department store.

In addition to the health risks, fragrances can also restrict access to certain places for some individuals. For example, some people are unable to use public restrooms or wash their hands with soap in public places due to the presence of fragranced products.

To reduce the potential health risks associated with fragrances, some precautions can be taken, such as wearing a mask if sensitive to fragrances, reducing time spent in fragranced environments, increasing ventilation, and using unscented products.

COVID-19 and scent sensitivity

COVID-19 is a respiratory infection that causes flu-like symptoms, including a dry, persistent cough and fatigue. One of the earliest signs of a COVID-19 infection is the loss of the sense of smell, or anosmia, which can be complete or partial. This loss of smell often leads to a loss of taste as well, as 80% of what we taste comes from what we smell.

COVID-19 does not seem to affect the olfactory sensory nerves responsible for smell or the taste buds. Instead, it seems to affect the supporting cells that surround the olfactory nerve. When these support cells are not working correctly, it can block the olfactory nerve's signals from reaching the brain, causing a loss or change in the sense of smell.

Some people may also experience parosmia after COVID-19, where things smell differently and often unpleasantly. For example, things that normally smell pleasant may suddenly smell like rotten food, garbage, ammonia, or chemicals. About 7% of people who experience loss of taste and smell during COVID-19 end up with parosmia.

Another condition that may be caused by COVID-19 is phantosmia, where people experience odors that don't exist. Phantosmia can be described as smelling sewage, rotten meat, rotten eggs, or moldy socks.

The changes in taste and smell caused by COVID-19 can be very distressing and make it difficult to enjoy food and social activities. Fortunately, these senses usually return within a few weeks or months, and there are treatments that may help speed up recovery.

If you are experiencing scent sensitivity or other smell-related issues after recovering from COVID-19, it is recommended to consult a doctor. They can provide guidance and treatment options, such as olfactory training or "smell rehab," which involves sniffing different strong scents daily to help retrain your sense of smell.

Migraines and scent sensitivity

Sensitivity to smell is a common symptom of migraines, with around 95% of migraine patients reporting scent sensitivity. This phenomenon is called osmophobia, a psychological hypersensitivity to smells. It is a well-known trigger or worsening factor for migraine attacks.

People with migraines often experience an aversion to smells they regard as unpleasant, such as the smell of raw food, cooking food, or certain foods in general. This aversion can be due to physiological or psychological causes, or a combination of both. When it is psychological, it is referred to as osmophobia.

During a migraine, many odors can be bothersome, with chemical fumes from cleaners and gasoline being the most likely to induce an attack. Other common triggers include perfumes, cigarette smoke, motor vehicle exhaust, and some cleaning products.

In some cases, people with migraines may experience olfactory hallucinations (OHM), smelling things that are not present. These cases are rarer, occurring in 0.1% of adults and 3.9% of children with migraines. The smells associated with OHM are usually unpleasant, such as burnt wood, smoke, or rotten meat, but can sometimes be pleasant, like melon, bananas, jasmine, or vanilla.

Scent sensitivity can also be related to hyperosmia, which is a heightened sense of smell caused by disease, pregnancy, nutritional deficiencies, or adverse reactions to medication. Hyperosmia and osmophobia can work together to induce a migraine attack, with hyperosmia causing smell hypersensitivity that triggers a psychological response in the form of osmophobia.

The exact reason for the link between scent sensitivity and migraines is not fully understood by doctors. However, it is believed that migraine may activate brain cell pathways that change sensory processing, altering how people perceive smells.

Allergies and scent sensitivity

Scents and fragrances can cause a range of adverse reactions in people, from mild irritation to severe health issues. While not everyone is affected, scent sensitivity is a common issue, and it can be especially aggravating when exposure occurs repeatedly in places like the workplace or at home.

Fragrance sensitivity occurs when your airways are irritated by ingredients or chemicals in natural or manufactured scents. It is characterised by symptoms such as sneezing, coughing, itchy eyes, and a ticklish or burning sensation in the nose. Fragrance sensitivity can happen to anyone, but is more likely if you have asthma or allergies.

Symptoms of Fragrance Sensitivity

The symptoms of fragrance sensitivity generally develop within minutes of exposure to a scent and can last from a few minutes to several hours. The severity of symptoms tends to be worse with longer exposure or stronger scents. In addition to the symptoms mentioned above, prolonged exposure to fragrances can lead to nausea, dizziness, and skin irritation, including rashes and dermatitis.

Fragrance Sensitivity vs. Allergy

Fragrance sensitivity is often used interchangeably with fragrance allergy, but they are not the same. A true allergy involves a whole-body immune response, where a protein called immunoglobulin E (IgE) triggers a chain reaction leading to allergy symptoms. Fragrance sensitivity does not involve IgE, and is limited to irritation of the airways and eyes. However, fragrance sensitivity can sometimes trigger an allergic response or an asthma attack, although the reason for this is not yet understood.

Prevention and Treatment

The best way to manage fragrance sensitivity is to avoid exposure to offending fragrances. This can be achieved by using unscented personal care products, opting for natural cleaning solutions like baking soda and vinegar, opening windows for ventilation instead of using air fresheners, and asking friends, family, and colleagues to avoid wearing strong fragrances or using fragranced products around you.

In cases where exposure is unavoidable or symptoms are persistent, over-the-counter medications can be used to treat the symptoms. For example, pain relievers can be taken for headaches, and nasal decongestants can be used for congestion. If fragrance sensitivity triggers asthma or allergy symptoms, it is important to take the appropriate medications to manage those conditions.

Endocrine, metabolic, and autoimmune disorders

Olfactory impairment has been linked to several neurological disorders, including Alzheimer's and Parkinson's diseases, as well as depressed mood. Recent studies have also investigated the sense of smell in the context of autoimmune diseases.

Research has revealed an association between an impaired sense of smell and autoimmune diseases such as systemic lupus erythematosus (SLE) and myasthenia gravis (MG). SLE is a chronic autoimmune disease that can affect multiple organs and systems in the body, and it has been found to cause disturbances in olfactory functions, which are linked to neuropsychiatric manifestations of the disease. MG is a rare autoimmune neuromuscular disorder characterised by fluctuating fatigue and muscle weakness, and it has also been associated with a decreased sense of smell.

The connection between autoimmunity and the sense of smell is further emphasised by studies on patients with other autoimmune diseases such as Sjögren's syndrome, polydermatomyositis, recurrent spontaneous abortion, and hereditary angioedema. These studies suggest that there may be a genetic and hormonal basis for the link between smell and autoimmunity, as olfactory receptor gene clusters are located near the major histocompatibility complex, a key locus of susceptibility for autoimmune disorders.

While the exact mechanisms are still being explored, the sense of smell plays a vital role in our perception of the environment and can have a significant impact on our physical and emotional well-being. Aromatherapy, which involves the inhalation of essential oils, has been practised for thousands of years and is believed to offer calming effects and improve sleep quality, reduce anxiety, boost mood, and ease depression.

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