Multiple Chemical Sensitivity

Last Editorial Review: 6/3/2011

What Is Multiple Chemical Sensitivity?

Multiple chemical sensitivity (MCS) is also called "environmental illness" or "sick building syndrome." It refers to a variety of non-specific symptoms reported by some people after possible exposure to chemical, biologic, or physical agents. Some say that levels of exposure generally considered safe for most people can have an effect on a few.

The symptoms people report are wide-ranging and not specific. They include headache, fatigue, dizziness, nausea, congestion, itching, sneezing, sore throat, chest pain, changes in heart rhythm, breathing problems, muscle pain or stiffness, skin rash, diarrhea, bloating, gas, confusion, difficulty concentrating, memory problems, and mood changes. 

People who have the symptoms may blame them on a major event, such as a chemical spill. Or they may point to long-term contact with low levels of chemicals at work, perhaps while working in an office with poor ventilation. Reported triggers include tobacco smoke, auto exhaust, perfume, insecticide, new carpet, chorine, and countless others.

Why Is MCS Controversial?

Multiple chemical sensitivity is controversial. Many experts and major medical organizations -- such as the American Medical Association and the American Academy of Asthma, Allergy and Immunology -- have stated that the connection between the patient's symptoms and environmental exposures are speculative and evidence of disease is lacking. The American Medical Association Council on Scientific Affairs believes that multiple chemical sensitivity should not be considered a recognized clinical syndrome. Yet some doctors and many people suffering with unexplained symptoms believe that it is.

So far, medical experts have not found a clear cause, test, or treatment for MCS. More research may be needed. It is clear that many people are suffering because of their symptoms and frustrated because they don't know how to get help.

How Common Is MCS?

Studies show that women between the ages of 30 and 50 are more likely to develop the symptoms. Symptoms are also more common among military personnel, particularly Gulf War veterans.

What Causes MCS?

There is no question that high doses of some chemicals make people sick and that irritants such as pollution and cigarette smoke worsen conditions such as asthma. What isn't as clear is how very low levels of chemical exposure affect us.

Experts can only speculate about the causes of these symptoms. Some speculate that it is an immune response similar to allergies. Others say that the symptoms stem from an extreme sensitivity to certain smells. It's possible that conditions such as depression and anxiety play a role.

How Is MCS Diagnosed and Treated?

There are no reliable established tests to help diagnose MCS and there are no effective or proven treatments. It is also unknown whether MCS can be prevented. Some doctors prescribe antidepressants, including selective serotonin reuptake inhibitors (SSRIs) such as Celexa, Luvox, Paxil, and Prozac. Other people find that medicines for anxiety and sleep help. Treating specific symptoms -- such as headaches -- may also have a benefit.

People often find solutions on their own. Some learn from experience that certain foods or chemicals seem to make their symptoms worse. Avoiding those chemicals or foods may help. Yet extremely restrictive diets, rigorously avoiding exposure to allergens and pollutants, or quitting a job can impose serious burdens on your life.

MCS and Working With a Doctor

People with these symptoms are often terribly distressed and desperate to find relief.

There are no proven ways to determine or treat this illness. Before you spend time and money getting specialized treatment -- or working with an environmental contractor renovating your house to remove possible triggers -- consider that we don't have good evidence that these approaches have medical benefits. Unproven treatments always have the potential to do more harm than good.

You need to work with a doctor whom you trust. Both you and your doctor should be cautious but keep an open mind about all the possible causes of your symptoms and the many possible treatments. Working together, you can find a safe way to get relief from your symptoms.

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American Academy of Allergy, Asthma, and Immunology: "Position Statement: Idiopathic environmental intolerances."

Asthma and Allergy Foundation of America: "Chemical Sensitivities."

Black, D. Archives of Internal Medicine, April 24, 2000; vol 160: pp 1169-1176.

United States Department of Labor: Office of Safety and Health Administration: "Multiple Chemical Sensitivities."

Reviewed by Brunilda Nazario, MD on June 03, 2011

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