Not long ago, the condition of Multiple Chemical Sensitivity (MCS) was typically dismissed by doctors as something existing entirely “in a patient’s head.” However, in recent years, awareness of MCS has really begun to gain traction in both the clinical and research spheres of medicine. Today, even the much-referenced WebMD has a definition for Multiple Chemical Sensitivity. According to WebMD:
“Multiple chemical sensitivity can include a wide range of symptoms, which some people link to their environment. It's also known as ‘environmental illness,’ ‘sick building syndrome,’ or ‘MCS.’ Your doctor may call it ‘idiopathic environmental intolerance.’
The symptoms people report are wide-ranging. They include headache, fatigue, dizziness, nausea, congestion, itching, sneezing, sore throat, chest pain, changes in heart rhythm, breathing problems, muscle pain or stiffness, skin rash, diarrhea, bloating, gas, confusion, trouble concentrating, memory problems, and mood changes.
Possible triggers that set off people's symptoms vary a lot, too. They include tobacco smoke, auto exhaust, perfume, insecticide, new carpet, chlorine, and more (“Multiple Chemical Sensitivity, n.d.).”
Symptoms of Multiple Chemical Sensitivity can vary from person to person. However, there is a characteristic set of symptoms typically found in people with MCS, when they are exposed to the particular chemicals that set them off. These symptoms include burning and stinging eyes, wheezing, shortness of breath, nausea, extreme fatigue, headache, dizziness, poor memory, rhinitis, sore throat, coughing, sinus problems, skin rashes, sensitivity to light and noise, sleeping issues, digestive issues, and muscle and joint pain (Multiple Chemical Sensitivity: What is it?, n.d.).
These symptoms can make life very difficult for people with MCS, as they often have to avoid areas that set off their symptoms, and unfortunately, many of the substances that make MCS people sick are quite prevalent in our environment. Car exhaust on the streets, the smell of other peoples’ perfume, lotions, or cologne, and cigarette smoke can be very hard to avoid in daily life.
The idea that someone could be hypersensitive to substances that don’t bother the general populace makes it hard for some to believe that MCS is a valid illness. However, for people who suffer from multiple chemical sensitivity, the challenges of this condition are all too real, causing extreme discomfort and in some cases, debilitation. Personally, I experienced MCS as one of the symptoms of my long-term illness, which involved Lyme disease and Toxic Mold Illness. For me, MCS was more than just a discomfort; it actually limited many aspects of my life for some time. Due to its impact on my life, I wanted to learn as much as I could about the condition, in the hopes that I could find a way to reverse it. To my disappointment, no doctor was ever able to explain to me any potential mechanisms behind MCS. They had no treatments specifically designed to address MCS. Doctors trained in conventional Western medicine are apt to prescribe antidepressants to patients who come to them suffering from MCS; I find this almost comical – it seems like conventional medicine’s answer to problems they don’t know how to solve is simply to prescribe antidepressants. Anyway, it basically seemed like Multiple Chemical Sensitivity was an anomaly with no clear solution. This lack of information about MCS really frustrated me.
Personally, I found that treating Lyme, coinfections, and mold decreased my MCS substantially (but that’s another whole article in itself). So while I am about 75% recovered in regards to MCS, I am still very interested in the subject. About a week ago, I was very excited to come across an excellent article published in the most recent issue of The Townsend Letter, an alternative medicine magazine written and edited by researchers, health practitioners, and patients. The article is titled “Potential Proof of Chemical Sensitivities” (Busby, 2016). The author of the article, Laurie Busby, did an excellent job of compiling the research on MCS, demonstrating potential proof of Multiple Chemical Sensitivity. Her article provides a lot of technical detail, which I was very excited about, but I wanted to be able to share some of the information she provided. As a result I have created a synopsis of some of the highly valuable information she found.
Potential Mechanisms of Multiple Chemical Sensitivity:
- Some infectious agents (i.e. bacteria, viruses) have been found to travel to and congregate in areas of the brain that may be associated with Multiple Chemical Sensitivity. In human autopsies, high levels of human herpes virus 6 (HHV-6) DNA have been found in the olfactory bulb/tract, which is the part of the brain that handles sense of smell (Harberts, Yao, Wohler, Maric, Ohayon, Henkin, Jacobson, 2011). HHV-6 has demonstrated a key role in the pathogenesis of Chronic Fatigue Syndrome, which often shares many symptoms of Multiple Chemical Sensitivity. Could this help explain why sick people with MCS develop such an acute sense of smell, and are thus irritated by smells that don’t bother the average person?
- Viruses injected into the nasal cavity enter olfactory neurons (sense of smell neurons), travel to the olfactory bulb, and then into the Central Nervous System, demonstrating a connection between the nasal cavity, sense of smell, and nervous system (Herbert, Harris, Chong, Chapman, West, Chuah, 2012).
- An initial environmental exposure/stressor, either infectious or chemical, may trigger damage to the epithelial tissue on the inside of the nose. This may initiate increased sensory neurogenesis (creation of new sensory neurons) as a repair mechanism, resulting in a more sensitive sense of smell (Feron, Mackay-Sim, Andrieu, Matthael, Holley, Sicard, 1999).
- In MCS and MCS-related health conditions, it has been found that “Preliminary data indicate the nasal pathology of these disorders is characterized by defects in tight junctions between cells, desquamation (shedding of the outermost membrane) of the respiratory epithelium, glandular hyperplasia, lymphocytic infiltrates, and peripheral nerve fiber proliferation” (Meggs, 1997). In other words, damage to the nasal passages and sensory neurons can occur as a result of an exposure to an infectious agent or toxic substance.
- Certain neuropeptides (substances that mediate nerve growth, pain, and inflammation) are increased in people with Chronic Fatigue Syndrome, Multiple Chemical Sensitivity, chronic rhinosinusitis, and infection. Some of the substances that are increased are Substance P (responsible for transmitting pain information), nerve growth factor (regulates the growth, maintenance, and proliferation of neurons), and bradykinin (an inflammatory mediator that dilates blood vessels and causes a drop in blood pressure). In addition, in people with viral infections there are decreases in certain enzymes needed to degrade the aforementioned substances (Busby, 2016). This could help explain the heightened olfactory sensitivity of people with MCS, as well as some of the symptoms of MCS that can be caused by dilated blood vessels, including contraction of smooth muscle in the bronchi (bronchoconstriction/shortness of breath), smooth muscle contraction in the gut (GI disturbances), and a drop in blood pressure (dizziness, faintness).
- TRPA1 and TRPV1 are receptors that are activated by pungent compounds, which would include strong scents. An ongoing viral infection or toxic environmental exposure activates these receptors. The high level of activation of these receptors in people with MCS could help explain the sensitivity of people with MCS to substances that are at low concentrations. If their TRPA1 and TRPV1 receptors are already being activated by a pathogen or toxin in their body, then they will have a lowered capacity to handle extra “stimulation” from substances outside their bodies, such as cigarette smoke and perfume (Busby, 2016).
- Finally, people with MCS may have lower levels of enzymes in their bodies that are needed to break down chemicals. These crucial enzymes are called xenobiotic-metabolizing enzymes (XMEs), and are found in the epithelium of the nose and nasal passages, the epithelium of the bronchi in the lungs, and in the skin. A lack of these enzymes could result in a lowered tolerance to xenobiotics, which are substances foreign to the body that include inhaled toxic compounds. In addition, polymorphisms or lower activity levels of the following genes may contribute to the development of MCS: CYP2C9, CYP2D6, glutathione S transferases (GSTM1 and GSTT1), N-acetyltransferase (NAT), and paraoxonase (PON).
The findings that Ms. Busby outlined in her article are fascinating, and provide much food for thought in terms of developing protocols for treating Multiple Chemical Sensitivity. To read her entire article, pick up a copy of the Townsend Letter November 2016 issue, or view the E-edition online at http://townsendletter.com/Nov2016/Nov2016.html.
Busby, Laurie D. (2016, October). Potential Proof of Chemical Sensitivities. The Townsend Letter, Nov 2016, 93-95.
Feron, F., Mackay-Sim, A., Andrieu, J.L., Matthael, K.I., Holley, A., Sicard, G. (1999). Stress induces neurogenesis in non-neuronal cell cultures of adult olfactory epithelium. Neuroscience, 88(2), 571-583. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/10197776.
Harberts, E., Yao, K., Wohler, J.E., Maric, D., Ohayon, J., Henkin, R., Jacobson, S. (2011). Human herpesvirus-6 entry into the central nervous system through the olfactory pathway. Proceedings of the National Academy of Sciences, 108(33), 13734-13739. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/21825120.
Herbert, R.P., Harris, J., Chong, K.P., Chapman, J., West, A.K., Chuah, M.I. (2012). Cytokines and olfactory bulb microglia in response to bacterial challenge in the compromised primary olfactory pathway. Journal of Neuroinflammation, 9:109. DOI: 10.1186/1742-2094-9-109.
Meggs, W.J. (1997). Hypothesis for the induction and propagation of chemical sensitivity based on biopsy studies. Environmental Health Perspectives, 105(Suppl 2), 473-478. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1469810/.
Multiple Chemical Sensitivity. (n.d.). WebMD [online]. Retrieved from http://www.webmd.com/allergies/multiple-chemical-sensitivity.
Multiple Chemical Sensitivity: What is it? (n.d.). MultipleChemicalSensitivity.org. Retrieved from http://www.multiplechemicalsensitivity.org/.