Multiple Chemical Sensitivity (MCS) is the name given to a syndrome in which a sufferer experiences multiple symptoms upon exposure to minute amounts of everyday chemicals. Because so little is known about it, especially what causes it, there is currently no officially recognised definition for MCS.
Leading theories suggest a hypersensitive central nervous system, immune dysfunction and impaired detoxification by liver enzymes. Despite a growing number of studies (308 out of 618) showing abnormalities in people with MCS on exposure to normally safe levels of chemicals, some medical professionals continue to insist (on the evidence of 137 out of 618 reports) that the syndrome is psychological in origin.
Although there is no universally accepted definition, MCS experts have come to a consensus on the criteria for diagnosis:
• symptoms reappear whenever the sufferer is exposed to the chemical;
• the condition is chronic;
• low levels of exposure trigger symptoms;
• symptoms improve or resolve when the chemical is removed;
• sufferers react to multiple unrelated chemicals;
• symptoms involve multiple organ systems.
Many MCS sufferers can trace the start of their illness to an acute exposure to highly toxic chemicals - Gulf War veterans or farmers using pesticides.
For other sufferers the illness develops over a long period of time usually involving chronic low level exposure to chemical substances. Although MCS can occur on its own, a large number of sufferers also suffer from CFS, fibromyalgia and other related disorders. This obviously points to the possibility that all these illnesses are part of the same underlying process and have common causes.
MCS is a chronic condition - the sufferer usually experiences some level of unwellness all the time. However, they have an acute reaction when exposed to minute amounts of the chemicals to which they are sensitive. Often the level of a chemical that triggers a reaction may be so low that the sufferer can't even smell it.
First published 2007
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