Multiple chemical sensitivity

Multiple chemical sensitivity (MCS), also known as "20th Century Syndrome", "Environmental illness", "Sick Building Syndrome", Idiopathic Environmental Intolerance (IEI), can be defined as a "chronic, recurring disease caused by a person's inability to tolerate an environmental chemical or class of foreign chemicals"  according to the NIH National Institute of Environmental Health Sciences web site.

History
Allergist Theron G. Randolph (1906-1995) coined the term “multiple chemical sensitivities.” He observed in his clinical patients that exposure to low levels to modern synthetic chemicals caused a wide range of symptoms. His observations challenged the toxicology maxim that there must be a correlation between level chemical dose and the level of symptom effect.

Randolph theorized that the human body is like a barrel filling up with chemicals until it is full. Any further exposure to chemicals causes allergic reactions, like the straw that broke the camel's back.

Cause of MCS
MCS etiology is hotly debated among physicians: some believe that MCS is the result of increase in exposure to irritants or a toxic injury, some believe that MCS is a physical illness with a yet-to-be-determined mechanism, and some believe that MCS is psychosomatic. Despite this debate, there is consensus that patients who complain of symptoms should avoid chemical irritants as best as possible. Respect in care and recommendation of avoidance of irritants is now standard protocol recommended by the American Medical Association.

Several chemical-producing companies, especially producers of pesticides, have funded studies that have cast doubts on the existence and cause of MCS.

Recent research by Dr Mariko Saito et al from the Department of Psychosomatic Medicine at the University of Tokyo seems to indicate a lack of evidence for the psychosomatic hypothesis. Their conclusion is that "MCS patients do not have either somatic or psychologic symptoms under chemical-free conditions, and symptoms may be provoked only when exposed to chemicals."

In a study involving 203 MCS sufferers and 162 controls, blood tests revealed that genetic differences relating to the bodies de-toxification processes were present more often in those with MCS than those without. People with two specific genes (CYP2D6 and NAT2) were 18 times more likely to have MCS than those without. They conclude that "A genetic predisposition for MCS may involve altered biotransformation of environmental chemicals." McKeown-Eyssen et al. 2004.

Some people with MCS say that they were injured by a single exposure to chemicals. Others say that they developed an intolerance to chemicals over time. Others are uncertain as to how their intolerance to chemicals developed. However, all agree that exposure to chemical irritants precipitates sometimes disabling symptoms such as migraine headache, sinus congestion, itchy eyes and throat, nausea and vomiting, indigestion, irritable bowel syndrome, constipation, bloating, rashes, asthma, muscle aches, joint aches, bladder problems, fatigue, flu like symptoms, depression, irritability, anxiety, mania, inability to concentrate, stupor, sleepiness, insomnia, tremor, paresthesia (loss of sensation), orthostatic hypotension.

Conventional medicine does not typically recognize the MCS diagnosis, because to date there is no definitive test for diagnosis or proven scientific mechanism. Symptoms may be explainable by allergic, metabolic, enzymatic, inflammatory,infectious, or psychological mechanism. Because the nature and cause(s) of MCS are still unanswered, conventional medical testing for legal purposes is not yet available.

In one blinded test, patients appeared to show no reaction to suspected substances. The same patients also seemed to react to saline solution injections and purified air injected into their environment.

Science recognizes that there are chemicals that build up in the body (such as mercury), but these are not yet recognized to cause allergic reactions. However, some people claim that after a meal of fish, they have an immediate bout of diarrhea. This may be another chemical sensitivity reaction.

Chemicals such as mercury can also cause organ failure, such as failure of the liver (which is involved in storing these chemicals) or the kidneys (involved in filtering them out). Some chemicals are also stored in body fat. These effects have never been found in MCS patients, either suggesting that they actually do not suffer from the effects of chemicals or that there is another mechanism (possibly the one Randolph proposed) to blame for their symptoms.

Medical doctors who treat MCS are called "clinical ecologists", and many belong to the American Academy of Environmental Medicine, which Randolph founded in 1965 as the Society for Clinical Ecology. Clinical Ecology is not recognized by the American Medical Association.

An alternative sensitization mechanism has been proposed by H.R. Eriksen and H. Ursin in a paper publicized April 2004. They propose the term "subjective health complaints" for MCS and a number of other conditions that are similarly “vague”, such as epidemic fatigue, chronic musculoskeletal pain, chronic low back pain, chronic fatigue syndrome, and fibromyalgia. According to them: "These complaints are particularly common in individuals with low coping and high levels of helplessness and hopelessness". They suggest that: "These complaints are based on sensations from what in most people are normal physiological processes. In some individuals these sensations become intolerable. In some cases it may signal somatic disease, in most cases not." In their conclusion they suggest that the psychobiological mechanisms for this is sensitization in neural loops maintained by sustained attention and arousal. This Erikson-Ursin “suggestion” is unproven.

For practical purposes, according to a patient survey by Alison Johnson, the most reliable way to achieve relief from symptoms and to create long-term improvement in health is to avoid the offending chemicals. However, the fact that specific chemical sensitivities have never been demonstrated in double-blind testing of MCS sufferers makes this a difficult proposition.

People diagnosed with MCS suffer widely assorted symptoms blamed on exposure to trace levels of environmental chemicals. In one person, formaldehyde may cause arthritis, in another insomnia, in another sore throat. In one person, insomnia may be caused by phenols, in another by MSG, in another by sulfites. This lack of correlation between symptom and chemical trigger makes research difficult.

It has been observed, however, that 85-90% of reputed MCS sufferers are women, and primarily middle class women, suggesting that there is a large cultural component to MCS.

Purported symptoms of MCS

 * anaphylactic shock
 * difficulty breathing, chest pains and asthma
 * skin irritation, contact dermatitis, and hives or other forms of skin rash
 * migraine headaches
 * "brain fog" (short term memory loss, cognitive dysfunction, including attention deficit)
 * exacerbation of neurological symptoms (example: nerve pain, paralysis, weakness, restless leg syndrome, etc)
 * extreme anxiety, panic and/or anger
 * suppression of immune system
 * digestive difficulties, nausea, indigestion/heartburn, vomiting, diarrhea
 * food intolerances, which may or may not be clinically identifiable (e.g., lactose intolerance, celiac disease): commonly wheat and dairy.
 * joint and muscle pains
 * extreme fatigue, lethargy and lassitude
 * vertigo/dizziness
 * abnormally acute sense of smell (which may simply be the result of ridding one's home of strong masking scents, therefore purging olfactory neurons)
 * sensitivity to natural plant fragrance, pine turpines
 * insomnia
 * dry mouth, dry eyes
 * overactive bladder

Treatment
Biological and chemical exposure - particularly long-term - is capable of causing many systemic disturbances, especially within the functioning of the immune and central nervous systems. Such exposures are also a proposed cause of psychological illnesses like depression, though studies in this area are often inconclusive and contradictory and so physicians have as yet no guide as to the proper diagnoses or treatment of such chronic effects.

In 2002, a survey of over 900 MCS sufferers seemed to indicate that the most effective options were removal of chemical irritants from the home and avoidance of the chemical irritants in general. Drugs intended for psychiatric conditions were reported among the least effective treatments. (Gibson et al. 2003)

Research conducted by Dr. Katherine Whited identifies avoidance as the most effective treatment. In the same study, 56% of participants who tried anti-depressants stated that "symptoms worsened" - by far the strongest negative response to all types of treatment surveyed. 

The lack of a proven medical method of diagnosis makes misdiagnosis more likely: some MCS patients suffer from depression, anxiety or other long term psychological problems. Because these conditions have alternative causes it has been posited that MCS is simply a physical manifestation of a psychological disturbance (a psychosomatic illness) which should be treated with psychotherapy and anti-depressants. The use of anti-depressants [specifically, SSRIs] with a number of patients has shown dramatic, albeit temporary, improvement; MCS proponants claim that this is because "it further increases the body's toxic load and temporarily masks symptoms."

About one half of the patients with MCS in various studies meet the criteria for depressive and anxiety disorders. (Lax MB, Henneberger PK. Patients with multiple chemical sensitivities in an occupational health clinic: presentation and follow-up. Arch Environ Health 1995;50:425-31.)

Irritable Bowel Syndrome provides an example of an illness with no definitive diagnostic test which is often mistakenly seen as psychological. It is now known that when IBS patients are put on special diets and improve, many of their "neurotic" symptoms disappear. (Brostoff J. Irritable Bowel Syndrome. N Engl J Med 1994)

Treatments offered by practitioners of environmental medicine specify the avoidance of known allergens and irritants, nutritional support to open up the body's various detoxification channels designed to purge the body of its toxic load, sauna detoxification, autolymphycyte factor treatment, allergy shots, experimental treatments and several other lifestyle changes.

Enclosed, air-conditioned buildings with a recycled air supply such as shopping centres or large office buildings are generally considered particularly bad environments for the chemically-sensitive. Some with MCS find it helpful to avoid certain types of fabric for their clothing, hang printed paper outside for days to air it out (or avoid it all together), use only untreated wooden furniture, use only organic food etc. Some avoid contact with the outside world all together in favor of a controlled environment which limits exposure to offending chemicals that otherwise cannot be avoided.

Suspected chemicals

 * bleach, fabric softeners, wool-wash, and detergents
 * perfumes, air-fresheners and anything scented or perfumed
 * petrol or gasoline, diesel and exhaust fumes
 * pesticides, fertilisers, and other agricultural chemicals
 * shampoos, hairsprays and personal care products
 * dishwashing liquid and detergent (may cause migraine headaches for those without MCS)
 * most glues (including carpet glue), varnishes, polishes, paints, solvents and paint-thinners
 * petroleum-based products (including petroleum jelly)
 * Formaldehyde and aldehyde
 * Tartrazine (a.k.a Yellow #5 or FD&C E102), and other Azo dyes
 * Caffeine

In particular, offgassing chemicals (some odorless, some not) are suspect.

Solvents are suspect, because there is debate in medical science that these can cause permanent brain damage after long exposure. The associated illness is popularly known as painters' syndrome, since (professional) painters are exposed to paint-thinner fumes on a daily basis for many years. For this reason, many countries have banned thinner-based paints and replaced them with water-based paints. There is however no evidence thinner causes damage to people only occasionally exposed to them. Non VOC, healthier paints may be obtained.

One hypothesis is that buildup of trace levels of chemicals is the cause of MCS. This would seem to make almost any substance suspect, since every substance is fatal if the dose is high enough. Some chemicals have a greater tendency to accumulate in the body than others, although MCS proponants have not yet put forward any evidence that chemicals that do accumulate are more likely to cause problems than those that do not.

Another hypothesis is that the chemicals triggers a coagulation response (which is also seen in 30% of allergic reactions) and that this is a non-IgE allergy response. In the case of MCS, there appears to be a genetic or acquire coagulation defect (for example Prothrombin 20210) resulting in a slow clearing of the coagulation products with the consequence of hypoxia symptoms and is some individuals, poor clearing of toxins from the body. Many individuals with MCS have triggers that are documented to be coagulation triggers:
 * Temperature
 * Electrical fields
 * Airline flights especially those longer than 2 hours
 * Fluorides and Fluoridation
 * Mercury
 * Exercise
 * Stress and Adrenaline
 * Fluorescent lighting (see with those with [Lupus] antibodies).

Many people with MCS also avoid exposure to inks, laser printers, and other potentially offgassing substances such as new furniture and plastic items.

MCS patients do not all agree about the possible etiology of the symptoms. While many believe that chemical or mold exposure is central to the etiology of MCS, others believe that their symptoms, including sensitivity to smell, are a part of a larger picture such as severe migraine with aura or depression—both of which involve neurotransmitters.

MCS has been reported to be reduced significantly with 4000 IU of Vitamin D3 daily over 6+ months. It has been suggested that a Vitamin D deficiency is a significant contributor to many auto-immune illnesses (as it is with multiple sclerosis).