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Allergies Health Center

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Multiple Chemical Sensitivity

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.

The symptoms people report are wide-ranging. 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, trouble concentrating, memory problems, and mood changes.

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People who have the symptoms may blame them on a major event, such as a chemical spill. Or some may link their symptoms to 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, chlorine, and countless others. Some say that levels of exposure generally considered safe for most people can have an effect on a few.

Why Is MCS 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. But some doctors and many people who have unexplained symptoms believe that it is.

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. How very low levels of chemical exposure affect people isn't clear.

Studies show that women between the ages of 30 and 50 are more likely to develop the symptoms. The reason for that isn't known.

Some doctors suggest 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, too.

How Is MCS Diagnosed and Treated?

There are no reliable tests to help diagnose MCS, and there are no effective or proven treatments.

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