Multiple chemical sensitivity syndrome seems to be triggered by exposure to low levels of several identifiable or unidentifiable substances commonly present in the environment.

• Symptoms may include rapid heart rate, chest pain, sweating, shortness of breath, fatigue, flushing, and dizziness.
• Tests may be done to rule out allergic disorders.
• Treatment may involve psychotherapy, avoidance of certain substances, or both.

Multiple chemical sensitivity syndrome is more common among women than men. In addition, 40% of people with chronic fatigue syndrome and 16% of people with fibromyalgia also have multiple chemical sensitivity syndrome.

Some doctors consider this disorder to be psychologic in cause, probably a type of anxiety disorder similar to agoraphobia (fear of going out in public) or a panic attack (see Anxiety Disorders: Panic Attacks and Panic Disorder). Others believe the disorder may be a type of allergic reaction (see Allergic Reactions and Other Hypersensitivity Disorders). Various changes in the immune system may occur, supporting the idea of an allergic reaction. However, there is no consistent pattern of such changes among people who have this syndrome, and the cause remains unknown.

Reported Triggers for Multiple Chemical Sensitivity Syndrome
Alcohol and drugs Caffeine and food additives Carpet and furniture odors Fuel odors and engine exhaust Painting materials Perfume and other scented products Pesticides and herbicides

Symptoms and Diagnosis

Some people start having symptoms after a single exposure to high levels of various toxic substances. People blame their symptoms on exposure to these substances, but evidence is usually lacking.

Symptoms may include a rapid heart rate, chest pain, sweating, shortness of breath, fatigue, flushing, dizziness, nausea, choking, trembling, numbness, coughing, hoarseness, and difficulty concentrating.

A doctor bases the diagnosis of multiple chemical sensitivity on the symptoms. The diagnosis is supported if the symptoms

• Recur after repeated exposire to the chemical substance
• Recur after exposure to levels much lower than those that have been tolerated previously or that are commonly tolerated by others
• Subside when the person leaves the offending environment
• Develop in response to a wide variety of unrelated chemical substances

Tests, including blood and skin prick tests, may be done to diagnose allergic disorders.

Treatment

Treatment usually involves trying to avoid the toxic substances thought to cause the symptoms. However, avoidance may be difficult because many of these substances are widespread. People should avoid too much social isolation. Psychotherapy is sometimes helpful, not necessarily because the disorder is psychologic, but because it helps people cope with their symptoms.

Last full review/revision December 2008 by Margaret-Mary G. Wilson, MD