Sandra K. McDonaldColorado State University

Multiple Chemical SensitivityAn increased sensitivity to chemicals in the

environment attributed to prior chemical exposure

Multiple Chemical SenstivityOther names:

Environmental illness (EI)Ecological illnessTotal allergy syndromeThe 20th century disease (Hileman, 1991)Idiopathic environmental intolerances (IPCS, 1996)

Multiple Chemical SensitivityTerm most commonly applied to a condition

that challenges patients, health-care providers & health & environmental agencies alike

Multiple Chemical SensitivityIn broad terms it means an unusually severe sensitivity or

allergy-like reaction to many different kinds of pollutants including :SolventsVOC's (Volatile Organic Compounds)PerfumesfuelsSmoke"chemicals" in general

MCS – Do We Understand?The idiopathic or "not understood" nature of MCS means

that doctors & others are often highly skeptical about the reality of – and nature of - the MCS condition

Many features of MCS and it’s effects and the way it’s effects are described by the sufferer seem altogether unrealistic, impossible or implausible to a conventional & scientifically trained consultant or General Practitioner

MCS First ReportTheron Randolph, 1952

Physician trained in allergy & immunologyReported a number of patients reacted

adversely to chemicals in their environment

MCS First ReportLinked the adverse effects of this

"petrochemical problem" to contact with chemicals found in commonly encountered substances i.e., cosmetics, auto fuels, exhaust fumes &

food additives

MCS First ReportObserved that many patients reacted to

many industrial solvents found in small amounts in manufactured products such as construction materials, newspaper & other ink-related products, furniture & carpet

American Academy of Environmental MedicineRandolph, 1965, founded Society for Human

EcologyIn response to this lack of acceptance

within his specialty1985, name changed to the American

Academy of Environmental Medicine Environmental physicians

MCS DefinitionsCullen’s (1987) definitions is widely used – four elements:

1. syndrome is acquired after a documentable environmental exposure that may have caused objective evidence of health effects;

2. symptoms are referable to multiple organ systems and vary predictably in response to environmental stimuli;

3. symptoms occur in relation to measurable levels of chemicals, but the levels are below those known to harm health; and

4. no objective evidence of organ damage can be found.

MCS DefinitionsCullen’s definition has the practical advantage

of describing a syndrome without specifying individual symptoms or mechanisms of disease

Multiple Chemical Sensitivity

Wide variety of symptoms have been reported(Terr, 1986; Lax & Henneberger, 1995)

Symptoms of MCSExtreme fatigueHeadacheGastrointestinal problemsMuscle & joint painDepressionMemory & concentration difficultiesAnxietyUpper airway irritation

Multiple Chemical Sensitivity

Patients have associated their symptoms with many substances(Ziem, 1992; Lax & Henneberger, 1995)

Exposures linked to MCSCarpet & upholstery

materialsConstruction materialsDeodorizersDisinfectantsFabricsNewspapersPaint

Perfumed ‘personal’ products

PesticidesPetroleum productsPlasticsWood preservatives

Multiple Chemical SensitivityPersons reported as suffering from MCS

present with outcomes that range from minor discomfort to severe disability

Americans with Disability ActIn 1991, multiple chemical sensitivity was defined as a

disability under the actResulted in the demand for accommodation at work, at

school and in housing for those with a diagnosis of MCSIn some states, MCS is recognized under workers'

compensation laws as a disability resulting in free health care for persons with symptoms related to the phenomenon, as well as payment for lost wages

Because a major treatment recommendation is avoidance of chemical exposure, the worker may never return to active employment

OSHA’s View on MCSwww.osha.gov/SLTC/multiplechemicalsensitivities/index.

htmlMCS is a highly controversial issueIn theory, MCS is an adverse physical reaction to low

levels of many common chemicalsChemical sensitivity is generally accepted as a reaction to

chemicals but debate continues as to whether MCS is classifiable as an illness

Proposed MechanismsTheories of the etiology of MCS can be

grouped into four broad categories: PhysicalStressMisdiagnosis Illness belief

Sparks 1994

Physical Three basic physical mechanisms have

been proposed to explain MCS: AllergyDirect toxic effects Neurobiologic sensitization

Simon 1993

AllergyChemical ecology movement believes

chemical exposure causes the development of allergy to low levels of many chemicals, not just the initiating one

Supporters point to a spectrum of immune system tests that have been found to be abnormal in patients with MCS

Multiple Chemical Sensitivity

Patients react to extremely tiny amounts of chemicals

Only mechanism which is now known to cause reaction to tiny amounts is antibody formation (i.e., allergy)

Some MCS patients react to chemicals which do not induce formation of antibodies

Multiple Chemical Sensitivity True allergies - where the underlying mechanisms of the

problem are relatively well understood widely acceptedMCS , is generally regarded as "idiopathic" - meaning that it

has no known mechanism of causation & it's processes are not fully understood

The problem here is made more difficult still, due to the variable nature of Multiple Chemical Sensitivity from one patient to the next & this often makes treatment with conventional medicine & practices ineffective or inappropriate; for most sufferers with Multiple Chemical Sensitivity, the avoidance of pollutants/toxicants is the key.

True AllergyAn acquired reaction caused by

an immune system response to one SPECIFIC excitant that has already been encountered at least once before

Miniscule Dose of a ToxicantSensitization is a true allergic reaction to one chemical or

irritant and is caused by involvement within the body of mast cells and IgE antibodies

Once sensitized to a particular irritant, a subsequent exposure to even a tiny amount of the same irritant even parts per million – ppm – or parts per billion – ppb

can cause an extreme allergic reactionone ppm = 0.0001 %

Toxicological EffectsOthers propose a toxicological effect of low-

dose exposure -- poisoningObjective evidence for such an effect is

lackingPatients with MCS experience symptoms at

levels of chemical exposure far lower than those considered toxic

Multiple Chemical Sensitivity

Miller et al. (1997) Theory of "toxicant-induced loss of tolerance"

(TILT)Acute or chronic chemical exposures might cause

certain susceptible persons to lose their tolerance for previously tolerated chemicals, drugs & foods Subsequently, even minute quantities of these &

other substances may trigger symptoms

Neurobiological SensitizationAffected persons develop increasing neurologic

sensitivity to the adverse effects of chemicalsAnimal models for such neurologic changes include

limbic kindling and time-dependent neurologic sensitization

These events have been documented only with pharmacologic doses and only in animals, not in humans and not at the low doses purported to cause MCS

SensitivityThis sensitivity, in the case of MCS, to unrelated toxicants

does, however, have several unproven, but seemingly sound theories to explain it including:Enzyme depletion Conditioning Immune system disorders

Enzyme DepletionEnzymes are also used to detoxify a wide range of

synthetic chemicalsIf the enzymes are depleted or damaged by health

problems, then they are unable to metabolize these toxicants efficiently, so leading to the problems associated with MCS

Many types of enzyme deficiency can be inherited Some (fairly tentative) evidence to suppose that MCS

may affect other members of the same family

ConditioningTwo unrelated events occur at the same time and one event

becomes associated with the otherWhen the first event is later repeated, the second event also

manifests itself for the suffererFor example, if on a particular day the patient is already feeling

slightly unwell and if, coincidentally, the patient is exposed to (say) paint fumes, then the paint fumes may genuinely make the patient feel unwell and possibly nauseous

A subsequent exposure to the same paint fumes - or a similarly strong solvent odor - may produce a strong feeling of nausea for the patient, who, moments before, felt perfectly well

Immune System DamageSome researchers are of the opinion that MCS is due to

immune system damage or malfunction, which could give rise to a sensitivity to all sorts of triggers rather than a specific reaction to one toxicant

Another important and debilitating feature of MCS - and which tends to complicate MCS diagnosis & treatment still further - is it's ability to apparently augment the effects of other problems experienced by the patient - problems such as common allergies, asthma, depression, food intolerances etc, & these problems of augmentation are reported by about half of all MCS sufferers

Sensitively ScepticismMain aspect of MCS sensitivity that is NOT fully

understood is that the MSC sufferer reacts similarly and in an allergic fashion to a whole range of completely unrelated toxicants "chemicals“SolventsPerfumesVOCsOdorsetc.

MCS TriggersCan change over time

A person who was not reactive to a particular substance may or may not react when exposed to the same substance at a later time

Vary between peopleNot all people react to all triggers

MCS Epidemiology

Most patients (85 -90 %) complaining of MCS syndrome are women

Most present between the ages of 30 and 50 yearsThe question of whether MCS is becoming more or less

common is unansweredAs is the question of whether it is preventable

Avoidance of “Triggers”Patients often significantly alter their behavior in an

attempt to avoid presumed precipitants of symptoms97 % of the patients had stopped activities outside the

home91 % had limited their travel89 % had limited their contact with friends77 % had left a job

Lax 1995

Avoidance of “Triggers”Many changed home routines:

97 % had stopped using cleaning compounds69 % removed home furnishings 63 % limited their contact with family members

In their personal care:94 % stopped using fragrances91 % changed their diet 86 % changed the type of clothing they wore

Lax 1995

MCS DebateValidity of MCS as a distinct disease

entityWhat role, if any, the biochemical

mechanisms of specific chemicals have in the onset of this condition

Multiple Chemical Sensitivity

No diagnostic criteria for itNo set of signs and symptoms which are

always found in persons who believe they are chemically sensitive

No objective blood or other laboratory test for MCS

Who gets MCS?

5% of U.S. population has severe MCS Greatly reduced quality of life

15-30% have less severe problemsWomen four times as likely to be

affected as menAverage age of onset is during 40’s

Coping with MCSNo cure at presentTreatment – avoid exposure IsolationGeneral lack of acknowledgment of MCS

within medical community

MCS & SocietyMultiple chemical sensitivity is not simply

a medical concern of diagnosis and treatment, but it is becoming a major social and economic issue with a strong activist agenda

Chemical Sensitivity: The Truth About Environmental Illness (Barrett and Gots 1998)

MCS & SocietyAdvocates of multiple chemical sensitivity have successfully

sought sympathy and support by attacking the chemical industry and others as the source of their plight

Numerous activist organizations publish newsletters and maintain Web sites that identify physicians and lawyers who support the chemical causality of their illnesses

A newsletter reports legislative, public policy and court decisions that support multiple chemical sensitivity as a legitimate disease or disability -- Our toxic times. Chemical Injury Information Network, White Sulphur Springs, Montana

Debated TopicsWhether MCS is a distinct disease

entityIts etiology (or etiologies)Its pathophysiologyHow to define the conditionHow it should be treatedHow it should be approached in legal &

legislative arenas

Questions?