Multiple Chemical Sensitivity [a.k.a Idiopathic Environmental Intolerance (IEI), 20th Century Disease Syndrome, Total Allergy Syndrome, Immune System Dysregulation, and Chemically Acquired Immunodeficiency Syndrome] refers to an unusually severe sensitivity or allergy-like reaction to a variety of pollutants such as Volatile Organic Compounds (VOC's), perfumes, smoke, petrol, diesel, solvents, chemicals in general, and can sometimes include sensitivity to pollen, house dust mites (HDM's), pet fur, and pet dander {1}. It is an acquired condition, which is typically initiated by a definable exposure to a toxic substance. Symptoms of MCS are provoked by very low doses of causal factors and may occur in various organ systems {2}. The mechanism of the cause of MCS is unknown and its processes are currently not fully understood; however, it tends to occur in people with a tendency to allergies or if allergies run in the family. Usually, individuals are well until at some point in their life they are exposed to certain chemicals, either in one large dose or in repeated small doses {3}.

The cause of MCS is unknown. It has however been suggested, but not proven, that chemicals travelling in the air enter the nose and affect an area of the brain known as the limbic system, which plays a role in emotions, motivated behaviour, and memory. This can make an individual more sensitive to chemical odour previously encountered. It has also been suggested, but with little evidence, that acute or chronic exposure to chemicals can cause susceptible people to lose tolerance for chemicals they could previously tolerate {4}. Some theories have suggested that the immune system of MCS patients is somehow damaged causing sensitivity to all sorts of triggers. Perhaps the most worrying feature of MCS is its ability to worsen the effect of other problems experienced by patients; these include depression, food intolerance, and asthma (to mention a few) {1}.

Individuals who suffer from MCS can have severe symptoms, which can interfere with their daily life and work. These symptoms generally occur in one of three categories: central nervous system symptoms, respiratory and mucosal irritation, or gastrointestinal problems {5}. As such, symptoms include, but are not limited to, a rapid heart rate, chest pain, sweating, shortness of breath, fatigue, tiredness which is not relieved by rest or sleep, flushing, dizziness, nausea, choking, trembling, numbness, coughing, runny nose (rhinitis), sore throat, cough, hoarseness, altered sense of smell, sensitivity to light and noise, skin rashes, itching skin, and difficulty concentrating.

MCS sufferers typically present with a firm belief that their symptoms are as a result of chemical exposure, and these symptoms are accelerated by a range of everyday chemicals and common environmental agents. These include,

1. Perfumes
95% of chemicals in perfumes and fragranced products are synthetic chemicals, which are derived from petroleum; these include benzaldehyde, benzyl acetate, benzyl alcohol, camphor, ethanol, and limonene, to mention a few. These are all known to have a negative impact on health particularly to the central nervous system {6}.

2. Pesticides
Acute exposure to pesticides is usually thought to be the initial trigger when the onset of MCS occurs suddenly in an otherwise healthy individual. Pesticides are potent chemicals, due to the fact that a considerable number of them are chemically related to war time nerve agents and as such have negative effects on the nervous, endocrine and immune systems These effects are expected of pesticides in order to kill pests and as such it is no surprise that humans can be affected negatively by their effects. Common pesticides include DDT (which is one of the most potent and has now been banned from a number of western countries), lindane, and chlordane, to mention a few {6}.

3. Household Cleaning Products
Most of the pollution in the average home comes from the use of common household cleaning products. According to the United States Environmental Protection Agency (EPA), only around three in ten of the thousands of chemicals used in household cleaning products have been safely tested. Common chemicals used in cleaning products include toluene, found in stain removers; hexane/ xylene, found in aerosol sprays; EDTA, found in bleach; and diethyl phthalate, found in a variety of products such as cosmetics, insecticides, and some food packaging {6}.

4. Natural gas
When natural gas burns, it produces hydrocarbon products such as methane, carbon dioxide and small amounts of carbon monoxide. Inhalation of these can cause adverse reactions. Individuals can be exposed to natural gas at home where it is used in heating systems, stoves and water heaters or at work, for people working with chemicals, petroleum, metals, glass, plastic, pulp and paper, to mention a few {6}.

5. Other triggers include, vehicle exhaust, perfumes in cosmetics, shampoo, tar fumes from roof or road, varnish, shellac, lacquer, nail polish, nail polish remover, marking pen, laundry detergent, hair spray, after shave lotion, etc.

The best way to manage MCS is to avoid the sensitising agents, which trigger symptoms. Complete removal (where possible) of the chemicals, which cause MCS symptoms helps eliminate exposure. Prevention of exposure provides the body with enough time to detoxify and heal itself; however, it would be quite difficult to eliminate a number of these agents since most are encountered on a day to day basis. As such, other treatment modalities need to be considered to help manage MCS.

Alternative treatment for MCS include,
1. Detoxification programs
These are detoxification programs involving a lot of exercise and sweating, as well as chelation of heavy metals. Oral chelation is a popular mode of detoxification, which helps to improve health and nutritional status by replacing toxic metals with essential elements. This form of therapy uses chelating agents such as ethylenediaminetetraacetic acid (EDTA) to tightly bind to heavy metals and remove them from the body, usually through urine. The concern with chelation therapy however is that chelating agents are not generally specific and as such it is possible that essential trace elements can be removed as well as toxic metals.

2. Nutrition
MCS sufferers are sometimes advised to avoid all suspect foods, which may trigger certain symptoms. It is thought that MCS sufferers have a higher likelihood of nutritional imbalances, particularly deficiency in magnesium. Intravenous infusions of vitamins and minerals such as, vitamin C and B vitamins, magnesium, and trace minerals, can have significant therapeutic benefits {6}.

3. Drugs such as antihistamines and steroids.

4. Immunotherapy is sometimes used as a mode of treatment to help sufferers develop a tolerance for certain allergens. This is carried out by injecting small amounts of many allergens just beneath the skin of the patient; however, tolerance may not develop for months or even years.

- Full assessment, including nutritional, neurological examination and selective skin tests

- Peak flow monitoring

- Keep a symptom and cause diary to monitor triggers

- Eliminate all toxins from your home

- Choose only unscented natural skin care and cosmetics

- Use natural detergents and cleaning products

- Replace all your cleaning products with a natural product range

- Remove all man made and chemically treated carpets and soft furnishings and replace with unbleached organic alternative

- Use organic pure cotton bedding for comfortable fume free nights

- Wear unbleached natural fibres, particularly close to your skin

- Avoid all processed foods

What is Multiple Chemical Sensitivity? www.multiplechemicalsensitivity.org/

Bornschein S., Forstl H., Zilker T. Idiopathic environmental intolerances (formerly multiple chemical sensitivity) psychiatric perspectives. J Intern Med 2001; 250: 309-321.

Multiple Chemical Sensitivity. Allergy UK . www.allergyuk.org/allergy_mcs.aspx

Allergies: Multiple Chemical Sensitivity. WebMD. www.webmd.com/allergies/guide/multiple-chemical-sensitivity

Magill MK., Suruda A. Multiple Chemical Sensitivity Syndrome. Am Fam Physician 1998; www.aafp.org/afp/980901ap/magill.html

Multiple Chemical Sensitivity (MCS). The Environmental Illness Resource. www.ei-resource.org/illness-information/environmental-illnesses/multiple-chemical-sensitivity-(mcs)

Ross GH. Treatment options in multiple chemical sensitivity. Toxicol Ind Health 1992; 8(4): 87-94.

http://www.ctds.info/multiple_chemical_sensitivity.html

Electrosensitivity UK

Chemical free ( UK )

The Chemical Sensitivity Foundation

Pesticide Action Network UK