Fibromyalgia - Risk Factors

Multiple Chemical Sensitivity. Multiple chemical sensitivity (MCS) is a term now used to describe conditions in which certain chemicals can cause symptoms similar to CFS or fibromyalgia in some people. It has also been observed in people with fibromyalgia. Experts have come up with criteria to help recognize people with MCS.

The symptoms are reproducible with repeated exposure to a chemical. (These are often common chemicals found in popular products, such as perfumes, fabric softeners, and air fresheners.)
The condition is chronic.
Symptoms can be produced by exposure to the chemical at levels lower than previously or commonly tolerated.
The symptoms improve when the chemical is removed.
Symptoms can be triggered by multiple substances that are chemically unrelated.
Symptoms involve multiple organ systems.

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Still, as with CFS and fibromyalgia, some experts are uncertain whether MCS is an actually medical condition or if it is psychologically based. In one study, for example, CFS patients who believed their problem was chemically triggered were exposed to either an active chemical or a placebo (an inactive substance). Both groups reported symptoms, including those exposed only to the placebo. It should be noted that everyone is exposed to many chemicals on a daily basis, and it is very difficult to determine if chemicals are responsible for specific symptoms.

Restless Legs Syndrome (RLS). About 15% of people with fibromyalgia have restless legs syndrome. RLS is an unsettling and poorly understood movement disorder sometimes described as a sense of unease and weariness in the lower leg that is aggravated by rest and relieved by movement.

Disorders Affected by the Sympathetic (also called Autonomic) Nervous System. Other conditions that commonly accompany fibromyalgia include chest pain and heart palpitations, mitral valve prolapse, and a sudden drop in blood pressure.