Module 3: OM2 11.1:Multiple Chemical Sensitivity

Profile of an MCS Patient:

1. Four groups of people have been identified:
   • industrial workers.
   • occupants of tight buildings.
   • residents of communities whose air or water is contaminated by chemicals.
   • individuals with personal exposures to various chemicals in indoor air, pesticides or consumer products.
2. Generally females in the 30 - 40 year age group.
3. High socio-economic status with a diversity of occupational and environmental exposures.
4. History of previous psychological disorders.

History and Examination:

1. Duration and severity of symptoms should be recorded in relation to repeated exposures in the workplace or environment. Detailed occupational history should be obtained, with past exposure to chemicals, fumes and dusts. Symptoms are generally reported after exposure to common household irritants.
2. Typical symptoms are headache, fatigue, lethargy, myalgias, difficulty concentrating. Symptoms may persist for hours/days and even weeks.
3. Inability to tolerate large variety of foods and drugs.
4. Varying degrees of social and occupational restrictions may be reported, including driving, grocery shopping, wearing certain type of clothing entering certain workplaces.
5. They usually do not have concurrent presence of other obvious occupational or environmental diseases such as asthma or allergic dermatitis. Some may present with respiratory symptoms of shortness of breath or chest tightness.
6. Physical examination is almost always normal.

Laboratory Evaluation:

Several techniques have been employed for the diagnosis of MCS including:

• provocation neutralization testing.
• chemical and food challenges.
• immunologic testing.
• inhalant challenges.
• serologic testing for EBV antibodies.
• autoantibodies.
• blood testing for organic hydrocarbons, pesticides and heavy metals.

Many of these tests have been investigated and have been found to be of no diagnostic value.

Testing to Exclude Differential Diagnoses:

Because MCS is ultimately a diagnoses of exclusion, routine laboratory testing to rule out other medical conditions that are suggested by clinical symptoms may be useful.

• Psychiatric and psychological disorders: Specific psychiatric evaluation may be necessary.
  Neuropsychologic testing is useful, especially if there is a history of exposure to neurotoxins.
• Immunological Disorders: Lymphocyte counts, circulating autoantibodies, circulating immunoglobulins, surface markers.
• Respiratory Disorders: Nonspecific airways challenge with methacholine or histamine.
• Other conditions with similar symptomatology:
  • Chronic Fatigue Syndrome
  • Chronic Epstein Barr virus syndrome
  • Candida Hypersensitivity

REFERENCES:

For the relevant legislation refer to the CD Module: Industrial Hygiene.

Postgraduate Diploma in Occupational Health (DOH) - Modules 3 – 5: Occupational Medicine & Toxicology by Prof Rodney Ehrlich & Prof Mohamed Jeebhay is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Permissions beyond the scope of this license may be available at http://www.healthedu.uct.ac.za/