Multiple Chemical Sensitivities (MCS) Definition

Barta et al. Multiple Chemical Sensitivity (MCS) : A 1999 Consensus. Archives of Environmental Health 54(3):147-149, 1999.

The consensus is signed by 34 researchers and clinicians with diverse MCS experience. It specifies 6 criteria for the clinical diagnosis of MCS, the first 5 of which are taken from a survey of 89 other clinicians with various perspectives on MCS published in 1993 (see Nethercott JR et al. Multiple chemical sensitivities syndrome: toward a working case definition. Arch Environ Health 1993; 48-19-26)

1. “The symptoms are reproducible with repeated [chemical] exposure.
   
   
2. The condition is chronic.
   
   
3. Low levels of exposure [lower than previously or commonly tolerated] result in manifestations of the syndrome.
   
   
4. The symptoms improve or resolve when the incitants are removed.
   
   
5. Responses occur to multiple chemically unrelated substances.
   
   
6. [Added in 1999]: Symptoms involve multiple organ systems."

The consensus statement also includes a review of epidemiological data on the high prevalence of MCS among Gulf War veterans, ME/CFS and FMS patients.