Multiple chemical sensitivity

Abstract

Multiple chemical sensitivity (MCS) is an enigmatic term and although this combination of symptoms has been written about for over 50 years, it is unclear whether this is a disease (a pathophysiological process with a molecular mechanism) or an illness (a subjective feeling of malaise). The Center for Disease Control and Prevention (CDC) does not recognize MCS as a disease (Spencer and Schur 2008). As implied by its name, MCS is a condition in which chemical effects are blamed for causing the subjectively experienced symptoms/complaints. The allergologist, Theron Randolph, was a major influence in the formation of a movement in the 1950s which called itself clinical ecologists and described for the first time the combination of symptoms which later came to be known as MCS. As he assumed the presence of an allergic pathogenic mechanism, he called this illness the “All Allergy Syndrome.” The idea of an underlying allergic pathogenic mechanism leads the affected persons repeatedly to allergologists, usually after dozens of specialists have already been consulted. Regardless of the diagnostic significance, a patch test using chemical substances is frequently requested. The fact that a positive patch test can only explain an allergic skin reaction and is of no use in explaining other diverse symptoms is often tenaciously ignored by these patients. In addition, these patients also demand specialized allergological procedures such as the lymphocyte transformation test, the histamine release test, or the mast cell degranulation test. The term sensitization has a double meaning in connection with the genesis of MCS. In allergology, sensitization means the immunological processes that are necessary for the immune system to react to an exogenous substance with an allergic reaction. In psychology the term sensitization is used when mental processes recur on repeated exposure after an initial incident. Allergologists and dermatologists are repeatedly confronted by both this conceptualization (sensitization, All Allergy Syndrome) and the wish for clarification by the MCS patients and their ideas about the genesis of MCS.