Environmental Illness / MCS

Environmental Illness / MCS: Overview

Alternative names: Multiple Chemical Sensitivity / MCS, Environmental Illness, Ecological Illness, Total Allergy Syndrome, Multiple Allergy, Chemical Injury, Chemical Sensitivity.

Chemical sensitivity disorder or Multiple Chemical Sensitivity (MCS) is defined as "an acquired disorder characterized by recurrent symptoms, referable to multiple organ systems, occurring in response to exposure to many chemically unrelated compounds at doses below those established in the general population to cause harmful effects."

Most of us need little convincing that our urban environments are polluted.  The belief that the food chain is contaminated with toxic chemicals is universal and readily validated.  The exact number of persons suffering from chemical sensitivity is unclear, but the rise in immune and nervous system disorders indicates that this problem is becoming more common, and somewhat more widely recognized.

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Everyone knows someone who is sensitive to particular household products.  We all recognize that people vary widely in their response to a room full of cigarette smoke – some people can ignore it easily while others react with stuffy nose, teary eyes, coughing, sneezing, shortness of breath.  It should be no surprise, therefore, to learn that scientists are now confirming that different people react differently to modern compounds such as dry cleaning solvents, perfumes, detergents, glues, waxes, pesticides and other common household and industrial chemicals.

The prevailing rational and scientific viewpoint is that although some people are sensitive to small amounts of one or a few specific chemicals, there is no general hypersensitivity to chemicals.  Scientifically oriented allergists, psychiatrists and occupational health clinicians suspect that the majority of "MCS" (Multiple Chemical Sensitivity) patients suffer from psychological disorders such as depression, anxiety reactions and somatization (bodily reactions to stress).

On the other hand, clinical ecologists (doctors who specialize in environmental illness), believe that MCS is a widespread condition caused by exposure to common foods, chemicals and other stressors that can sensitize people, causing them to react adversely to even tiny amounts of these substances.

Both inorganic compounds (such as carbon monoxide, nitrous oxide and heavy metals) and organic compounds (pesticides, formaldehyde, phenol, etc.)  are involved.  A major indicator of chemical sensitivity is multi-system disease: this is because once the chemicals enter the body, they enter the bloodstream and circulate to all parts of the body, even the brain.

Incidence; Causes and Development

MCS is thought to afflict somewhere between 2% and 15% of the American public, and appears to be increasing, according to a publication of the American Chemical Society.

It has been suggested that MCS is not the best name for this family of ailments because it fails to reflect the importance of the initiating chemical exposure.  Toxicant Induced Loss of Tolerance (TILT) better describes the true nature of the illness(es) initiated by a toxic exposure which leads to the loss of tolerance of common chemicals.  Different initiating events may give rise to somewhat different ailments, all of which cause sensitivity to chemicals – just as different infectious diseases can all cause a fever.

There are over 70,000 chemicals commercially produced in the United States today.  The long-term, low dose effects of many of these chemicals have never been investigated.  With the construction of closed buildings, the rise in use of toxic construction materials, and an increase in the use of office machines, an environment of indoor air pollution has been created.  Some 60% of indoor chemicals are generated by products or machines used indoors.

The main mechanism for chemical sensitivity seems to be the failure of the body's enzyme detoxification pathways to adequately clear chemical compounds.  Both immune and non-immune processes have been involved.  Chemical sensitivity can develop after a massive chemical exposure, after specific non-chemical events such as massive trauma or surgery, after severe infections (viral, bacterial, parasitic) or with no identifiable cause.

Because most of the toxic chemicals involved are fat-soluble, they become stored in the body's fat, resistant to metabolism and excretion.  In fact, chemical levels measured from fat biopsies are sometimes 300 times greater than circulating serum levels.

Signs and Symptoms

Some people react violently to chemicals, to the point of being made ill by very low doses of common substances.  The possible list of symptoms is almost endless, varying from one patient to the next.  Most sufferers of MCS complain of at least several of the following:

  • burning, stinging eyes
  • wheezing, breathlessness
  • nausea
  • extreme fatigue / lethargy
  • headache / migraine
  • vertigo / dizziness / disorientation
  • poor memory / concentration
  • runny nose / stuffiness
  • sore throat, cough
  • sinus problems
  • skin rashes
  • itching
  • sensitivity to light / noise
  • sleep problems
  • poor digestion
  • swelling
  • muscle / joint pain.

The poorly-understood nature of MCS means that doctors are often highly sceptical about the reality and nature of the MCS condition.

Two important phenomena to understand regarding the symptoms are spreading and switching.  Spreading occurs when additional organ systems are involved, or when a patient additionally becomes sensitive to inhalants, foods, dust, animal danders, or other environmental exposures.  Switching occurs when the same exposure produces entirely different organ involvement e.g. photocopier fumes initially caused headache, and subsequently caused no headache but wheezing.

Diagnosis and Tests

The timing of symptoms after exposure, reproducibility of the symptoms, spreading, and switching must all be investigated.  Serum levels of suspected chemicals confirm the diagnosis.  If serum levels are negative and suspicion is high, a fat biopsy must be performed to complete the diagnosis.  Additionally, chemical challenge tests can demonstrate the cause-and-effect relationship between a chemical exposure and symptoms.

To distinguish between MCS and other allergy-related illnesses, the following deciding criteria apply:

  • The patient reacts to both large and often extremely low levels of irritants/toxicants/triggers
  • Other individuals present at the same time may be unable to detect anything at all unusual
  • The problem is chronic, not a 'one-off' event
  • The same symptoms are reproducible with repeated exposure to the same triggers
  • The patient is affected by many different triggers
  • The patient improves when triggers are absent.

Treatment and Prevention

MCS is difficult to treat due to its variable nature from one patient to the next.  Treatment with conventional medicine and practices is therefore often ineffective or inappropriate; for most sufferers with Multiple Chemical Sensitivity, the avoidance of pollutants/toxins is the key.

Signs, symptoms & indicators of Environmental Illness / MCS:

Symptoms - Abdomen

Symptoms - Allergy

Symptoms - Cardiovascular

Heart racing/palpitations

Heart palpitations and dysrhythmias can be caused by chemical exposures in sensitized individuals.

Symptoms - Food - General

Symptoms - Gas-Int - General

Symptoms - Metabolic

Symptoms - Mind - Emotional

Symptoms - Mind - General

Symptoms - Muscular

Specific/severe muscle weakness

The muscular weakness may be due to a nerve problem caused by chemical exposure and immune system changes associated with MCS.

Symptoms - Nervous

Symptoms - Respiratory

Symptoms - Skeletal

Conditions that suggest Environmental Illness / MCS:


Autoimmune Tendency

Reports of autoimmune markers in MCS patients, like most MCS data, are inconsistent.  Drs. Alan LeVin and Vera Byers in 1992 reported finding anti-thyroid and anti-smooth muscle antibodies among MCS patients, leading to the conclusion that some MCS patients may develop autoimmune disease: The immune systems of MCS patients may generate antibodies to chemicals, or to their own tissues, the latter of which may activate an autoimmune response.  In some cases, MCS could be viewed as a chemically-formed autoimmune disease. [Environ Health Perspect 105(Suppl 2): pp.417-36 (1997)]



An irregular or rapid heart beat and awareness of your heart beating are listed as possible symptoms of environmental illness.



Chronic Fatigue / Fibromyalgia Syndrome

MCS is a distinct illness that many times is diagnosed secondarily to CFS and/or fibromyalgia.


Risk factors for Environmental Illness / MCS:

Symptoms - Muscular

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Environmental Illness / MCS suggests the following may be present:


Allergy to Foods (Hidden)

People with multiple chemical sensitivities often have multiple food allergies as well.  While reactions to chemicals in the environment are generally quicker and more easily identified, food allergies are usually delayed, making it harder to pinpoint the offending food.  People with MCS are often unaware of hidden food allergies which could be contributing to their overall allergic load.

Environmental Illness / MCS can lead to:



Migraine/Tension Headaches

Central nervous system dysfunction is common, resulting in headaches, chronic fatigue, poor short term memory, hyperactivity, and increased appetite leading to food cravings and overeating.


Excessive Fatigue

Daytime grogginess is a possible symptom of environmental illness.

Environmental Illness / MCS could instead be:



Respiratory complaints among MCS patients include adult-onset "asthma", shortness of breath, and fibrotic lung disease.

Recommendations for Environmental Illness / MCS:


Dental Metal Removal

Hypersensitivity to dental metals and nickel is frequent in patients with CFS and MCS-like syndromes.  Ongoing metal-induced inflammation can be present in the oral cavity and/or in any other place of metal deposition.  Metal-driven chronic inflammation may affect the hypothalamic-pituitary-adrenal axis (HPA-axis) and trigger a myriad of non-specific symptoms characterizing CFS, MCS and other related diseases.  The removal of metallic restorations can reduce lymphocyte sensitization and improve the health of patients. [Neuroendocrinology Letters, 20: pp.289-298, 1999]


Sauna Detoxification Program

To decrease the fat stores of chemicals, a heat (sauna) detoxification program has been developed consisting of selected nutrients, colon cleansing, heat therapy and massage.  The protocol of nutrients, colon cleansing and heat therapy can often reduce the serum levels of these chemicals to "non-detectable".

Liver Detoxification Phase II Support

Reducing the body burden of chemicals can be enhanced by maximizing Phase II liver detoxification pathways with selected nutrients.


Chemical Avoidance

Avoidance of chemicals, especially those you are sensitive to, is the first step in treatment.  Face masks and air filters can minimize exposures when total removal is not possible.  Circulating clean air into confined spaces will help, but total removal of oneself from the source should be accomplished whenever possible.


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