Do you wear cologne every day? How about hairspray? Many people carry hand sanitizer, and almost everyone wears deodorant. In any public place, it would be a challenge to not come into close proximity to the large percentage of people who use these products as part of everyday hygiene preparation. Now, imagine how your life would change if you had a condition in which mere exposure to these products could endanger your health and well-being. Further still, imagine if the legitimacy of your condition was debated among health organizations, doctors, the public, and your peers.

Veronika Kos, a student at Vancouver Island University, has learned to navigate both the stigmas and stimuli associated with her sensitivity to fragrant chemicals. Kos experiences severe respiratory reactions from fragrances—often inhibiting her breathing entirely.

When she was in Grade 9, Kos was diagnosed with asthma after repeated episodes of dangerously restricted breathing. The diagnosis coincided with a painful family loss, causing anxiety attacks that exacerbated her symptoms and complicated her treatment options. It didn’t take long for Kos to notice her sensitivities to fragrances: namely perfumes, strongly scented lotions, and sanitizers.

“You’re never not aware of everyone who is around you,” Kos says with regards to her scent sensitivity. “There are people at work and at school who I know wear heavy fragrance, so I have to avoid them.”

For her asthma, Kos is prescribed daily medication and an emergency inhaler which she keeps close at all times. The severity of her reactions depend on the potency of the product, how recently it was applied, and her proximity to it.

“I can deal with light scents for a period of time. If it’s a really light scent, it gradually accumulates to the point where I’ll have to leave and use my inhaler, but it’s really bad for my lungs,” Kos says.

It becomes especially difficult when people are unaware or forgetful of her sensitivity.

“I had an incident at work where someone sprayed perfume while I was right beside them. I barely had enough time to make it to the back room and use my inhaler—I literally almost passed out.”

In coping with her asthma, Kos has frequently had to miss work, school, and social engagements.

“It’s frustrating. I hop on the bus and there’s always perfume. Depending on how bad it is, I have to get off and wait for the next one,” Kos says.

While most of her friends are accommodating toward her condition, Kos still encounters people who are unsympathetic or sceptical of her reactions.

“I’ve had people who just became annoyed with my sensitivity, so they decided to wear perfume regardless of what I’d say. I’ve also had co-workers accuse me of faking my asthma attacks so I could go home,” she says.

Part of the reason scent sensitivity remains an overlooked issue is due to the complicated nature of its causes and symptoms, which make it difficult to construct a specific medical diagnosis. For people like Kos, the sensitivity can safely be attributed to asthma, but what about non-asthmatics who display scent-induced respiratory symptoms? Or what about people whose symptoms manifest in other ways? How can health practitioners effectively treat their patients without the recognition of certain chemical sensitivities as a valid condition on its own?  

Giving it a name

Generally, Multiple Chemical Sensitivity (MCS) is regarded by the medical community as a chronic condition where low-level exposures to common chemicals can invoke a range of symptoms in the affected person. Headaches, rashes, muscle and joint aches, fatigue, memory loss, confusion, and asthma-related attacks are all symptoms associated with MCS.

The severity of reactions and the types of irritants vary greatly between individuals with the condition, making it difficult for researchers to isolate it as a distinct clinical condition. A 2018 article published by JH Lange for the Journal of Headache and Pain Management titled “Multiple Chemical Sensitivity: A Neurotoxicity Issue,” explores the potential causal relationships leading to MCS symptoms:

“It is likely that much of these diverse characteristics observed are a result of genetic polymorphisms and an increasing variety of chemicals in today’s environment. Some of these events are also likely due to complex interactions among chemicals and gene systems; although, any relationship has not been clearly established in the literature.”

In 1999, the international medical journal Archives of Environmental Health (volume 54, number 3), published the first consensus definition on Multiple Chemical Sensitivity, signed by 34 medical researchers and clinicians from the United States and Canada. According to the definition, MCS is diagnosed according to six criteria:

  • Symptoms are reproducible with repeated (chemical) exposures.
  • The condition has persisted for a significant period of time.
  • Low levels of exposure (lower than previously or commonly tolerated) result in manifestations of the syndrome (i.e. increased sensitivity).
  • The symptoms improve or resolve completely when the triggering chemicals are removed.
  • Responses often occur to multiple chemically unrelated substances.
  • Symptoms involve multiple-organ symptoms (runny nose, itchy eyes, headache, scratchy throat, ear ache, scalp pain, mental confusion or sleepiness, palpitations of the heart, upset stomach, nausea and/or diarrhea, abdominal cramping, aching joints).

Confounding variables

The 1999 consensus, while frequently cited, has not yet been universally adopted. The condition has been a contested issue among medical researchers, included only under a broader definition for Idiopathic Environmental Intolerance (IEI).

According to a 2017 study published by the Journal of Occupational and Environmental Medicine titled “Multiple Chemical Sensitivity: Review of the State of the Art in Epidemiology, Diagnosis, and Future Perspectives,” by Sabrina Rossi, MSc, and Alessio Pitidis, MSc, Multiple Chemical Sensitivity and IEI are often mistakenly seen as interchangeable, although the physical risk factors of IEI extend into foods and electromagnetic sensitivity:

“Although over the years, the researchers have made several steps toward a better definition of this syndrome, it is still not possible to diagnose MCS with absolute certainty, as the many and diverse symptoms […] are common to various pathologies, both physical and psychic.”


Of the varying illnesses correlated with MCS, Fibromyalgia and Chronic Fatigue Syndrome are frequently diagnosed in concurrence with the condition, often encompassing a crossover of non-specific symptoms. Statistics Canada, in a health report titled “Medically Unexplained Physical Symptoms (MUPS) among Adults in Canada: Comorbidity, Health Care Use and Employment,” notes that these illnesses are often associated with “…symptoms which do not appear to have a distinct etiology or ‘hard’ pathophysiological findings.”
The “vague,” and “unexplained” nature of these symptoms further hinders progress toward classification:

“Of those with chronic fatigue syndrome, 30% also had fibromyalgia, and 15% had multiple chemical sensitivity. Among individuals with fibromyalgia, 23% had chronic fatigue syndrome, and 13%, multiple chemical sensitivity […]. This overlapping raises the question of whether MUPS, which may be unique in their etiologies, all result in a more or less ‘common manifestation’ of symptoms, [sic]” (Statistics Canada, 2014).
Living with Multiple Conditions

Joe Blackburn, a published author and student at Vancouver Island University, has extreme reactions to a variety of chemicals. Living with Crohn’s disease, arthritis, and Chronic Fatigue Syndrome, Blackburn says that new, unique sensitivities began manifesting themselves as his autoimmune illness worsened.

“I grew up with my mom and her boyfriend smoking in the house, which never caused me any acute issues. After I became ill, I had a much stronger reaction to smoke, perfumes, deodorants, and detergents,” he says.

After recognizing his triggers, Blackburn had to begin adjusting his lifestyle in ways similar to Kos: avoiding certain places, people, and products. For Blackburn, however, the symptoms manifest themselves in a multitude of ways.

“It depends on how active my immune system is at the time. At worst, it can send me into a period of days with brain fog, headaches, mucous, extreme fatigue, and itchiness. In a lot of cases, my scent sensitivities are a manifestation of my overactive immune system,” he says.

On top of the inconveniences pertaining to his surroundings, Blackburn’s chemical sensitivities cause him a considerable amount of stress.

“It affects my social life, and my willingness to show up in class. I have anxiety too, because I’ve developed fears around certain smells due to reactions I’ve had.” As for addressing his chemical sensitivities with classmates and colleagues, Blackburn generally refrains from bringing it up:

“I go through periods where I feel resentful of people wearing fragrances, but I don’t like to put other people out to serve my needs. I try to meditate and have mindfulness. People are going to smoke, and people are going to use Tide laundry detergent—I have to navigate through that,” he says.

While Blackburn acknowledges MCS as a separate condition, he believes that the elaborate relationships between body, brain, and spirit constitute complex systems that modern science is unable to explain.

“Conventional medicine really dropped the ball with me for my Crohn’s disease. I think there’s an interconnectivity going on that sometimes modern medical science doesn’t recognize,” Blackburn says. “All things work in synergy.”

University policies and procedures

At Vancouver Island University, where both Kos and Blackburn attend class, there is no policy on scent sensitivity, according to Student Relations. As with any public institution, the prospect of entirely prohibiting scents is seen as impractical and difficult to enforce. VIU’s approach toward protecting scent-sensitive staff and students operates on a case-by-case basis, and falls in accordance with policies 41.09 (Health & Safety), and 32.02 (Services Available to Employees and Students with a Documented Disability). The latter highlights VIU’s legal duty to “remove barriers that inhibit full participation by students with a documented disability,” and to provide “reasonable academic accommodation” to such students.

For this reason, students who require a scent-free learning environment are advised to ask professors to help accommodate them. Their request shouldn’t be met with any resistance. After all, many individuals with MCS-related conditions can’t breathe, focus, or concentrate around fragrances; clearly preventing them from full academic participation. At the request of students, these policies have facilitated a scent-free environment in specific buildings. Students are also permitted to hang posters in order to raise awareness and promote a respectful academic environment in regard to scents.

MCS as a disability

In Canada, MCS is considered by the Ontario and Canadian Human Rights Commissions to be a disability. According to the 2014 Canadian Community Health Survey, about 2.4 percent of Canadian children and adults had been diagnosed with MSC by a healthcare provider. Across the board, the condition occurred more in women (one million) than in men (390,000). With such a small percentage, many people with the condition feel marginalized and dismissed by the public as having an psychosomatic or “imaginary” disease—causing them to remain silent about their symptoms and avoid being vocal to protect their health.

Opposing viewpoints

While many institutions enforce policies for the safety of people with chemical sensitivities, it isn’t always received well by people who don’t have the same reactions. Madeline (name has been changed for privacy), an office employee in Nanaimo, feels that these policies infringe on her right to wear whatever products she wants.

“It makes me a target in my office,” she says. “I literally don’t wear anything anymore—no perfumes or lotions—and the bare minimum is still an issue in my office. That’s where I draw the line.”

Madeline feels like her initial reluctance to comply with her office’s policy may have provoked resentments from her scent-sensitive co-worker, making the issue more personal as opposed to health-related.

“It didn’t matter if I wore no deodorant or not. They made me feel unwelcome at my job, and things got increasingly uncomfortable.”

According to Madeline, the scent-free policy in her office is ill-defined and informal by encouraging a “smoke-free” environment, while requesting the “limitation” of fragrances. Madeline says the policy is only punishable by “scorn.”

“I’m willing to accommodate someone with scent sensitivity, all the way. But when it starts to become a huge interference on my life, then maybe they need to relocate. I shouldn’t have to change my deodorant or laundry soap,” Madeline says.

Having been employed in multiple offices over time, she also says she has noticed the increasing prevalence of workplace etiquette that make many feel as though they’re “walking on eggshells.” While Madeline acknowledges the importance of workplace safety, she feels that the compromises can become unbalanced.

“I don’t want anyone to suffer in silence, as I wouldn’t want to myself, but I’ve noticed that the majority is being condemned for less and less. It’s my right to be as stinky as I want with my perfume.”

Correlation with Psychiatric Disorders

Unfortunately, the stigma behind Multiple Chemical Sensitivity is compounded by its occasional occurrence with psychiatric disorders. Statistics Canada reported that “19% of those with multiple chemical sensitivity met the criteria for at least one of six selected mental disorders: major depressive episode, bipolar disorder, generalized anxiety disorder, and abuse of/dependence on alcohol, cannabis or other drugs. [sic]”

A 2017 study titled “The Association between Multiple Chemical Sensitivity and Mental Illness: Evidence from a Nationally Representative Sample of Canadians,” published in the Journal of Psychosomatic Research by Dylan Johnson and Ian Coleman, investigated the correlations between MCS, Generalized Anxiety Disorder (GAD), Major Depressive Disorder (MDD), severe distress, and positive mental well-being.

While the cross-sectional study’s main findings showed a positive association between these conditions, a causal mechanism remained unclear. The study considers the possibility that individuals with mental health disorders already have sensitivities which show up in a similar symptomatic fashion to MCS:

“It may be that individuals with MDD and/or GAD have increased sensitization to stimuli in general, or also that they use external stimuli to explain their mental-health-related symptoms.”

In an attempt to (somewhat) balance their hypotheses, the study also acknowledges that MCS may precede the onset of mental illness—but the symptoms may be worsened by bringing them into focus as a separate condition altogether:

“…if genetic, metabolic, and other physiological factors negatively influence how individuals react to chemicals in their environment, individuals may find their symptoms of MCS distressing enough to induce psychopathology, which in turn, may negatively influence chemical intolerance symptomatology.”

Resources and solutions

Regardless of its definition, etymology, and contested status as a valid condition, chemical sensitivity is real. It exists. Everyone’s experience is unique, and it would be unfair to dismiss someone’s symptoms based on a lack of conventional medical consensus. You wouldn’t eat peanuts next to someone if you knew that it could potentially kill them (hopefully, anyway).

Thankfully, awareness about Multiple Chemical Sensitivity is growing. This is partly due to a more vocal community identity with groups like the Chemical Sensitivity Foundation and MCS Canada. The networks created by such groups aid in helping people in identifying and reporting their symptoms.


Considering how different each case is, the treatments and life changes in dealing with chemical sensitivities vary greatly. For Blackburn, the avoidance of chemicals is simply part of his life now.

“I try and be a proponent of natural products where I can. I mostly use baking soda to wash my clothes. My soaps only have two or three ingredients, and I don’t keep any harsh cleaning products in my house,” he says.

Blackburn also feels that not enough is being done to reduce the amount of harmful additives that we consume and apply every day.

“I think it’s not even in mainstream consciousness that these chemicals are a big issue. I wish it were, and not just for me. It’s so clear to me how pesticides and all these other toxins are major contributors to chronic illness.”

Kos concedes that scent-related policies are difficult to enforce.

“You can’t check people at the door. People wear products for a variety of reasons, including cultural ones. You’re also not going to stop people from having opinions,” she says.

She feels that if you are someone who exhibits symptoms of MCS, it helps to connect with others who share your experience, regardless of the symptomatic differences.

“Try to understand how you are similar, and how you differ. Different people have different needs when it comes to those sensitivities, and have different ways of asking for help when managing those symptoms,” Kos says.

Above all else, she feels communication is essential: “People don’t realize how serious it is until you’re having an attack. Don’t be afraid to be vocal and speak up.”