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by Sharon Wachsler

In this 2009 article, Sharon Wachsler discusses the relationship between ME/CFS and MCS. The More resources section has been updated in 2015.

What's the connection between CFIDS and MCS?

There is a great overlap between the Chronic Fatigue and Immune Dysfunction Syndrome/Myalgic Encephalopathy (CFIDS/ME) and Multiple Chemical Sensitivty (MCS). Although it is possible to have MCS without hav­ing CFIDS/ME, most people that I know with MCS have also been diagnosed with CFIDS/ME. Likewise, studies of people with CFIDS indicate that from one-quarter to three-quarters meet the diag­nosis for MCS.                .

A significant difference between CFIDS/ME and MCS is that whereas alleviation of CFIDS/ME symp­toms is often difficult or impossible, alleviation of MCS symptoms—in the form of avoidance of chemical exposures—almost always provides some relief. People with MCS who remove allergens and chemical triggers usually experience a great reduc­tion of their symptoms and may even slow or stop the progress of the disease. Many people who start out with mild MCS become more severely ill as they are exposed to more and more chemicals. An individual with CFIDS/ME who suspects s/he may also have MCS and takes steps to remove and avoid triggers, may help prevent future debilitation.

What are the signs and symptoms of MCS?

The symptoms of MCS are remarkably similar to those of CFIDS/ME. They include rashes and skin irri­tation; burning, watering, dry or itchy eyes; earaches or ringing in the ears; sore throat; headaches; runny nose or congestion; muscle pain and/or weakness; pain and tingling in the extremities (hands and feet); gastro-intestinal problems (stom­ach ache, gas, diarrhea); nausea, dizziness; fatigue; brain "fog"; lack of coordination; difficulty con­centrating; anxiety or mood swings; vomiting; fainting; seizures; and many other symptoms.

Because of the great range of MCS symptoms and their similarity to CFIDS/ME symptoms, other in­dicators are usually necessary to suggest MCS.

Here are some additional indicators that might suggest a PWC has MCS:

  • Gradual onset of illness (as opposed to acute on­set)— the patient got sick over a period of weeks, months or years.
  • Onset of illness triggered by an accident or chemical exposure. Examples are a medical procedure, especially if it involved getting general anes­thesia or injection of dyes, or other exposure to chemicals; a new house, a new school or work­place, and/or new carpeting, furniture, or heating system; use of, or proximity to, paints, pesticides, industrial cleaners or solvents, adhesives, or other construction materials; exposure to polluted water or air (whether acute or long-term).
  • Any known or suspected food allergies, inhalant allergies (such as dust, pollen, mold, animal dander, etc.), or chemical sensitivities (such as per­fume or tobacco).
  • A worsening of symptoms over time (both in number and severity).
  • Sudden onset or cessation of symptoms without apparent cause or explanation. Examples: someone comes to visit and you realize that you've devel­oped a headache and sore throat that you didn't have before; or you walk into the kitchen and sud­denly you have a horrible "brain fog", or you go outside and after a half hour you feel better (or worse) than you have all day.
  • Sensitivity (bad reactions) to medications.

Note: Because a person with CFIDS fits more than one of these categories, it does not mean that s/he necessarily has MCS—many of these can be true for people who just have CFIDS—but it may suggest that a PWC would want to at least have MCS ruled out.

Doesn't a person always know if s/he has MCS?

Sometimes yes, and sometimes no. In fact, I re­cently spoke with a woman who did not have any fatigue, but who was experiencing many CFIDS-­like symptoms (including headaches, nausea, dizzi­ness, sore throat, and pain and numbness in her extremities). She and her doctor were baffled.

Af­ter speaking with her, I suggested that she might have MCS and that she consult a clinical ecologist and the Massachusetts Association for the Chemically Injured. The reason that it is not always obvious that one has MCS is that if a person is reacting to everything around him/her, s/he feels sick all time and might not make the connection to specific exposures. Also, because some reactions to an exposure can be delayed—by hours or even days—it can be difficult to pinpoint the trigger.

Additionally, because MCS is not a well-known or respected diagnosis among the medical community (1), most people do not know what MCS is or what to look for. Finally, the issue of denial can play a role. For instance, long before I realized that I had MCS, I had hints that I was bothered by chemicals (such as perfume). I chose to ignore these signs because the idea of MCS—with its additional bur­dens—was too fearful for me to face.


(1) MCS is even less accepted than CFIDS/ME. Most doctors treat MCS as a hoax or a psychiatric disorder. Even allergists, who may be helpful in identifying some allergens and triggers, are usually not knowledgeable of or interested (in fact may be hostile to the concept of) MCS. 

What can I do if I suspect I have chemical sensitivities?

  1. You can consult with a clinical ecologist—a doctor who specializes in "environmental medi­cine." (See the resource list at the end of this arti­cle). Or if you can't pay for the doctor, you can self-diagnose by keeping a diary that lists all your activities and symptoms. After a while, a pattern often emerges.
  2. Throw out or remove everything that you know or suspect makes you sick. This includes any scented products (perfumes, hairspray, scented shampoos and soaps), cleaners (floor wax, furni­ture polish, scented laundry detergent), paints and petrochemicals, etc.(2) The best first step, especially if you live with other people, is to make a stripped-­down "safe-room" out of the bedroom, where no toxins are allowed. Usually, as the triggers are re­moved, MCS sufferers experience a gradual (or sometimes dramatic) reduction in their symptoms.
  3. Contact a MCS Organization that can provide you with more information and support. (See en­closed resource list at end of article).


(2) Many people with MCS react to natural gas. If one suspects MCS, s/he might want to have the gas stove and/or furnace shut off for a few days to see if her/his symptoms change.

More resources  

American Academy of Environmental Medicine
Phone: (316) 684-5500
Email: This email address is being protected from spambots. You need JavaScript enabled to view it. A physician's organization—you can search for members who practice environmental medicine in your area.


Chemical Injury Information Network Provides information and referral to members; publishes a monthly newsletter. Maintains a library on chemical injury.


Human Ecology Action League, Inc.
PO Box 49126
Atlanta, GA 30359 Information clearinghouse with chapters and support groups around the country.


Massachusetts Association for the Chemically Injured (MACI)
PO Box 754
Andover, MA 01810-0745
(978) 681-5117
Fax (978) 686 0745
This email address is being protected from spambots. You need JavaScript enabled to view it. Information, referral and support for people with MCS. Also holds monthly meetings and publishes a newslet­ter.


Multiple Chemical Sensitivities Referrals and Resources—an organization with a wealth of resources for patients and health care providers.


National Center for Environmental Health Strategies Focuses on initiating change and empowering the public with hard data, such as medical, legal, and policy in­formation. Provides information on gaining accommo­dations at work and school.