Diagnosing multiple chemical sensitivities

By Mithila

MCS is a condition characterised by a complex array of symptoms affecting multiple organ systems, as a result of low-level exposure to chemicals over time. Click here for an introduction to MCS. Due to the scientific uncertainty about the underlying mechanisms of MCS and consensus on its treatment, individuals who report MCS are often poorly understood, misdiagnosed, and given less than optimal health care. Despite the scientific knowledge on MCS being in its early stages, governmental organisations and clinicians are addressing sensitivity to a range of chemical substances. In the Australian state of NSW, 2.9% reported being medically diagnosed with MCS. Similar rates were reported in North America (2.5%) and Canada (2.4%). Many more cases of MCS are unknown, and given the loss of productivity and reduced quality-of-life associated with MCS, it’s evident that it warrants sincere investigation.

Too often, MCS has been dismissed as purely a psychological disorder caused by psychosomatic responses to perceived chemical toxicants. However, the American Medical Association, American Lung Association, U.S. Environmental Protection Agency, and the U.S. Consumer Product Safety Commission (1999) jointly addressed the importance of treating MCS as a physical disease, stating “complaints [of MCS] should not be dismissed as psychogenic, and a thorough workup is essential”. Current research recognising MCS as a physical disease suggests that hypersensitivity to chemicals may arise through sensitisation from genetic susceptibility, and/or toxic overload. Repeated exposure to triggering chemicals is thought to result in chronic inflammation which induces oxidative stress, leading to multi-system impairment.

Immune dysfunction

Many symptoms of MCS indicate an inflammatory reaction. Common symptoms such as migraines and confusion, have been strongly linked to neuroinflammation. Flu-like symptoms such as runny nose and sore throat, chronic dry eyes, oedema, dermatitis and gastritis are well-defined inflammatory reactions. IBS, a potentially disabling symptom of MCS, has been reported to arise from low-grade inflammation. Chronic fatigue is also a symptom of MCS, and long believed by researchers to be involved in chronic inflammation. In one study, pro-inflammatory cells were observed to influence symptoms of anxiety, depression and cognitive dysfunction — symptoms commonly misdiagnosed as primarily a psychiatric disorder in individuals with MCS.

As several symptoms of MCS indicate immune dysfunction, comprehensive medical testing of inflammatory markers may support diagnosis and treatment. Under the guidance of medical professionals, individuals may benefit from trialling anti-inflammatory treatments such as antihistamines, hydrocortisone, or mast-cell stabilisers, to relieve the immune-mediated reactions.

Current clinical practices

While there is no single diagnostic test for MCS, research suggests that the clinical presentation of signs, symptoms, and history supports tracking and treatment. At this time, a diagnosis of MCS is based on self-reported symptoms, and chemical exposure histories. There are no standardised treatments for MCS, however the most common management strategy is to avoid agents that trigger symptoms. Treatments advocated for MCS include dietary changes, detoxification and desensitisation techniques, nutritional supplements, prescription medicines, and behavioural therapies.

The Allergy Unit at Royal Prince Alfred Hospital (NSW), over decades of blinded experiments observed that patients presenting with recurrent and unexplained symptoms reacted to various foods and additives. These symptoms included chronic urticaria, angio-oedema, abdominal pain, diarrhoea, respiratory symptoms, headache, and other non-specific symptoms such as excessive sweating and chronic pain. Through this research, an elimination diet Free of Additives and Low in Salicylates, Amines and Flavour Enhancers (FAiLSAFE) was developed. Similar to other elimination diets, the protocol involved:
1) strict restriction of natural chemicals (namely salicylates, amines, glutamates) and additives (such as colours and preservatives)
2) methodical challenge of a food substance to assess its effect upon consumption
3) removal of the challenge food substance until baseline symptom level was reached and maintained
4) re-challenging of the same food substance or another
Elimination of environmental triggers such as fragrances, cleaning agents and cooking odours were also recommended for effective treatment.

Recommended treatment

First-line treatment involves eliminating chemical triggers specific to the individual’s chemical exposure history. For example, if the individual has repeatedly reacted to the smell of perfumes in the past, all fragrances should be eliminated during the protocol. Often the breadth of chemical sensitivity is unknown, and broad-spectrum avoidance of problematic additives, and common food allergens is recommended initially.

A conservative approach to avoidance of natural, whole foods is crucial; and no more than necessary should be eliminated. Avoidance of problematic additives in a range of food and non-food products is to be prioritised. As additives provide no nutritional value, there is no risk in eliminating them. Other common environmental triggers such as tobacco smoke, mould, chlorine should also be avoided. Challenges to determine a specific sensitivity should be limited to one particular food item or ingredient at a time, so as to more precisely determine cause. Symptom baseline following failed challenges should be sustained for a reasonable amount of time before another challenge, so as to minimise biasing effects of delayed reactions.

The overarching treatment goal is to reduce or silence reactions to chemical triggers, with an emphasis on reintroducing natural foods whenever possible. In treating children, people with a history of anaphylaxis, or other vulnerable individuals with symptoms of MCS, professional medical or dietetic expertise is necessary.

Science-based information to empower people in managing their food intolerances and chemical sensitivities

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