What is Chemical Sensitivity?
People who are sensitive to a chemical get symptoms from exposure to low levels of that chemical - levels that do not cause symptoms in most people. For example, being near cigarette smoke or perfume or car exhaust may give someone sensitive to chemicals asthma or a headache. It is like an allergy, in that people react to things that don't affect other people, but the biological mechanisms are different.

How common is it?
In the New South Wales Adult Health Survey 2002, 2.9% of people taking part reported that a doctor had diagnosed them with chemical sensitivity and 24.6% reported sensitivity to chemical odours. In South Australia 0.9% of people taking part in state health surveys reported that they had been diagnosed with MCS.(1)

What is Multiple Chemical Sensitivity (MCS)?
People with Multiple Chemical Sensitivity (MCS) are sensitive to many chemicals and have symptoms in more than one organ system. MCS ranges in severity from mild to extreme.

The 1999 Consensus Statement criteria for Multiple Chemical Sensitivity (MCS) are:
1. The symptoms are reproducible with (repeated chemical) exposure.
2. The condition is chronic.
3. Low levels of exposure (lower than previously or commonly tolerated) result in manifestations of the syndrome.
4. The symptoms improve or resolve when the incitants are removed.
5. Responses occur to multiple chemically unrelated substances.
6. Symptoms involve multiple organ systems.(2)

What are the symptoms of chemical sensitivity?
Chemical sensitivity can cause many symptoms. These include dry or sore eyes, headaches including migraines, fatigue, asthma, shortness of breath, rhinitis, blocked nose, sinus pain, sore throat, earaches, nausea, bloating, diarrhoea, constipation, poor concentration, confusion, memory problems, depression, anxiety, hyperactivity, sleep disturbance, joint pain, muscle pain and rashes.

What are people with MCS sensitive to?
Car exhaust, diesel fumes, perfume, aftershave, air freshener, fragrances, washing powders, chlorine, polyester, formaldehyde, foam, plastics, rubber, pesticides, insecticides, herbicides, mothballs, disinfectants, paints, solvents, gas, newsprint, cigarette smoke, wood smoke, artificial colourings, flavourings, preservatives and other food additives.

The majority of people with MCS also have food allergies/sensitivities. Allergies to moulds, dust mite and pollen are common. Some people with MCS are also sensitive to sunlight (photosensitivity) and/or electro-magnetic radiation.

What causes chemical sensitivity?
People can become sensitive to chemicals after a major toxic chemical exposure or after long-term, low-level exposure to toxic chemicals, eg pesticides. Chemical sensitivity can also occur after a virus or other illness, or with hormonal disturbances, eg during or after pregnancy.

A number of genes have been linked to MCS. People with mast cell disorders can be sensitive to chemicals. People with allergic conditions such as hayfever or asthma seem to be more likely to be sensitive to chemicals.

How is chemical sensitivity diagnosed?
Doctors test for chemical sensitivity with sublingual drops, intradermal injections and/or exposure in a booth. Immune tests often show abnormalities. Food sensitivities are usually tested for with an elimination diet and food challenges with single foods.

How is chemical sensitivity treated?
The main treatment is to avoid the chemicals or other substances that cause symptoms. Depending on how severe the problem is, this may involve:
Changing to more natural and non-toxic personal care products, cleaning products, clothing, bedding  and furniture.
Removing toxic products from the home.
Using non-toxic methods to control pests.
Using non-toxic or less-toxic building materials when building or renovating.
Moving to a less polluted area.
Eating organic food.
Using a good air purifier and/or water filter.

Workplaces, schools, hospitals and other places can be made safer for people with chemical sensitivities. Chemical sensitivity is considered a disability for the purposes of the Disability Discrimination Act. The Australian Human Rights Commission includes information about improving access for people with chemical sensitivities in their Access to buildings and services: Guidelines and information: http://www.humanrights.gov.au/publications/access-guidelines-and-information#chem

Some nutritional supplements and other treatments can be helpful to people with chemical sensitivities, but they are not a substitute for avoiding toxic chemicals.

What is the prognosis?
Many people can become free of symptoms by avoiding chemicals they are sensitive to. A few people make a full recovery and are no longer affected by low levels of chemicals. MCS is worsened by continued exposure to toxic chemicals and improves with long term reduction in exposure. Occasionally MCS is fatal.

1. Fitzgerald DJ (2008) Studies on self-reported multiple chemical sensitivity in South Australia. Env Health 8: 33-39.

2. ‘Multiple chemical sensitivity: a 1999 consensus’ 1999 Archives of Environmental Health Vol. 54(3):147-9. 

© AESSRA Inc. 2008, 2016 

Further information
AESSRA Inc. is not responsible for the content of websites linked to from its site.

Ashford NA, Miller CS, Chemical Exposures: Low Levels and High Stakes. Second edition. New York, John Wiley and Sons, Inc., 1998

Australian Government Department of Health and Ageing Office of Chemical Safety (OCS) and National Industrial Chemicals Notification and Assessment Scheme (NICNAS) Multiple Chemical Sensitivity Review Factsheet

Australian Government Department of Health and Ageing A Scientific Review of Multiple Chemical Sensitivity: Identifying Key Research Needs Report prepared by the National Industrial Chemicals Notification and Assessment Scheme (NICNAS) and the Office of Chemical Safety and Environmental Health (OCSEH) November 2010

Canadian Human Rights Commission:
The Medical Perspective on Environmental Sensitivities
By Margaret E. Sears (M.Eng., Ph.D.)

Independent Living Research Utilization:
Understanding & Accommodating People with Multiple Chemical Sensitivity in Independent Living 
By Pamela Reed Gibson, PhD., James Madison University


Allergy and Environmental Sensitivity Support and Research Association Inc.

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