Multiple Chemical Sensitivity Syndrome

Self-reported multiple food intolerances/sensitivities have been reported to be frequently associated with Idiopathic Environmental Intolerance (IEI), formerly called Multiple Chemical Sensitivity (MCS) Syndrome .  In 1987, Cullen introduced the term “multiple chemical sensitivities,” which he defined as “An acquired disorder characterized by recurrent symptoms, referable to multiple organ systems, occurring in response to demonstrable exposure to many chemically unrelated compounds at doses far below those established in the general population to cause harmful effects.  No single widely accepted test of physiologic function can be shown to correlate with symptoms.”  Other terms for IEI/ MCS are cerebral allergy, chemically induced immune dysregulation, total allergy syndrome, and ecologic illness.

The most common complaints are fatigue, headache, nausea, malaise, pain, mucosal irritation, disorientation, and dizziness, which are mostly non-specific.  No gross or microscopic evidence of inflammation or other objective signs of pathology have been associated with IEI/MCS.  As in somatoform disorders, these patients have multiple chronic symptoms and have previously consulted with numerous physicians and other health care professionals without satisfaction nor any finding of underlying immunologic, autoimmune, or any physical disease to explain their symptoms.  Patients attribute their illness to exposure to a combination of environmental chemicals, multiple foods, and drugs.  A unique feature of IEI is the general absence of a dose-response curve in the provocation of symptoms.

Evidence is growing in support of a causal role of underlying psychiatric illness, specifically somatoform, depression, and panic disorder in IEI/ MCS.  IEI and panic disorder share common symptoms such as chest tightness, breathlessness, and palpitations; apprehension; and avoidance of situations that have been associated with onset of symptoms.  Panic attacks may temporarily occur with non-noxious stimuli that are then associated with symptoms by the patient and are subsequently considered the cause of the symptoms.  Reports of placebo-controlled studies using saline infusions, carbon dioxide inhalation, and provocative challenges note that these approaches provoke symptoms suggestive of panic disorder and anxiety syndrome with hyperventilation in IEI/ MCS patients.  Evidence for a common neurogenetic basis linking IEI and panic disorders was reported in a study of 11 IEI patients who were found to have a significantly increased prevalence of cholecystokinin B (CCK-B) receptor alleles, which are known to be associated with panic disorder, compared to age-, sex-, and ethnic background-matched controls.

From: “Psychological Considerations in Food Allergy” Chapter in Food Allergy: Adverse Reactions to Foods and Food Additives, 3rd ed, Blackwell Science

LINK: Multiple Chemical Sensitivity Syndrome Has Strong Psychological Component

16 thoughts on “Multiple Chemical Sensitivity Syndrome

  1. What a complete joke. Once again, we hear it’s all in our head. Well, understand this. My brother and sister and I lived in an agricultural community from March, 1966 to August, 1967. We were exposed to crop dusting for days on end.

    I reacted immediately, with a complete intolerance of anything scented. I suffered from constant headaches and sinus infections. My brother and sister did not react so quickly. My brother went on to become a photographer, who developed many of his own photos, while, I avoided chemicals like the plague.

    I have diabetes… an auto-immune disease

    My sister has rheumatoid arthritis… an auto-immune disease

    My brother has just been diagosed with leukemia, often triggered in adults by long-term chemical exposure.

    Sure, it’s all in our heads.

    The use of chemicals in the US since WWII, is destroying our planet, along with those of us who are the canaries in the coal mine.

    New Mexico


  2. The facts you mentioned in your comment do not make sense. Millions of people have diabetes and rheumatoid arthritis who were never exposed to crop dusting. If your premise was true, then most of the people exposed to crop dusting would have developed similar problems, which is not the case and the incidence of rheumatoid arthritis and diabetes should be decreasing instead of increasing with less use of crop dusting. Leukemia has been linked to toxic chemical exposure, but what chemicals was your brother exposed to?
    The purpose of science is to point us in the right direction so we can search for treatment and cures. Irrational claims based on anecdotal evidence without scientific proof only wastes everyone’s time and prolongs the suffering of people who have a real disease.


  3. Yes, many people exposed to crop dusting have not developed similar problems….Genetics plays a part in what types of diseases we develop or are predisposed to in life, in addition to environmental factors. Crop dusting may be decreasing, but the chemicals we are exposed to in our homes, on our clothing and bedding, and in the environment has skyrocketed. Too bad for those who have the “wrong” genes


  4. There are several issues here.

    One, Multiple Chemical Sensitivity or MCS is still called that by most people except for those who are promoting the theory that it is a psychological illness.

    Two, if you want to know about MCS studies, go to pubmed and look there. The studies finding MCS has a physical cause and those finding it has a psychological cause are about evenly divided. there is no consensus among researchers.

    If you have MCS or know someone who does, just about everyone with the illness agrees that the best treatment is not doctors, or medications, or testing, but avoidance, avoidance, avoidance, of the substances that bother you. Many of us get better. In fact, I feel much better now than I did before I got MCS when I was supposedly healthy: I have learned what chemicals and foods cause me to feel bad and am able to avoid them. The more you avoid things in the beginning, the more tolerance you develop and can often slowly reintroduce many things back into your life, or find a way around them to live a pretty normal life. May we all be healed.

    Best wishes,



  5. I can always tell when I’ve found someone who doesn’t know anyone with MCS.
    My mother has MCS (as do a couple friends that she has met via the internet), and many people (family and friends) have seen first-hand that it isn’t JUST psychological, regardless of “scientific proof”. BTW, there was no “scientific proof” that the earth revolved around the sun for quite some time after it was first claimed either.

    If you want proof, how about some of the odorless chemicals that are used? How about the ever-popular Febreeze that makes smells vanish?
    My mom and her friend visited her mother’s house once (I don’t recall the reason, but they were there for 10-20 minutes or so). Both of them said that they felt aweful that night and the next morning (regular symptoms of their MCS, which they have under control most of the time) as if they had gone shopping in a mall or around other people (of which they hadn’t). Mom’s friend mentioned this to her mom a few days later and she mentioned that she had used Febreeze on the couch they sat on a couple days before they came by.

    Even though they couldn’t smell it or sense it in any way, they both had the reactions to the chemicals in the Febreeze because it IS a physical reaction. I have yet to find someone who dismisses MCS as a “mental ailment” to explain that… and that’s just one example of many that people with MCS live with.


  6. Exactly what kind of “reactions” did your Mom and her friend have? I see a lot of people with real and not-so- real allergies, and many people attribute their symptoms to allergies when there is a totally different reason for them and wind up practicing elaborate and difficult avoidance measures to things that they weren’t allergic to in the first place. Has your mother and her friend seen an allergist who replicated their symptoms in a blinded, controlled setting ? That’s what is done to study people who claim to have MCS. Maybe they’ll be the first to actually have a positive result.
    This site does not discount people’s symptoms, but merely tries to combat the massive scamming and misinformation that goes on on the Internet about MCS.
    If you really want to help your mom and her friend, tell them to see an allergist who can properly evaluate them, instead of just diagnosing themselves with a non-existent disease.


  7. This case has a genetic component – four generations of us! … mine is simply the most painful. MCS is the latest diagnosis/reason for chronic sinusitis, with opacification, old polyps, sinus balls surrounding unknown “spots” on CT scans. Having undergone virtually every designer antibiotic and steroid,my ENT tells me the answer to halt triggers to severe sinus/eye pain can be found on the internet, but I can no longer read or view a tv or computer monitor. Smoke from Florida fires, exhaust fumes, fertilizers, etc. are primary triggers for pain. How does one avoid them? I’ve remained on candida diet for years, new state-of-the-art AC/Heat system,EVERY suggestion of allergist/ENT’s – we’ve done. Biaxin/Diflucan were used recently for months – diverticulitis put an end to use of most drugs. Surgery is not an option. We’re seniors, going broke on all this experimentation. Any ideas for a “cure”, other than leaving the planet???


  8. First of all, I have yet to meet a responsible person who will tell you that the cure to a disease can be found on the Internet. Chronic sinus disease and polyps are a real and very serious problem. Have you had airborne allergy testing and if positive have you tried allergen immunotherapy and have you been evaluated for aspirin sensitivity (Samter’s triad) as well as other conditions that are associated with chronic sinusitis/ nasal polyps like cystic fibrosis?
    What does your sinus CT show?


  9. If reading this didn’t make me so angry it would be hilarious. As someone who is presently suffering from breathing difficulty, migraines, eye burn, nostril burn, and skin burns from contact with people in my office who use air freshners and strong perfumes, I would like to ring this person’s neck. I have always had reactions from perfume, spray cleaner, diesel smoke, magic markers, but it has gotten extremely bad in the past 6 months or so. I can’t imagine gummy eyes and phlem thick enough to blow bubbles with in my throat when I breathe!


  10. Have you been evaluated by an allergist? A lot of people attribute their symptoms to MCS when there are many other scientific based reasons to explain their condition, some of which may actually be treatable.


  11. Not so long ago it was a scientific fact that the sun revolved around the earth and it was a scentific fact that the earth was flat. Many paid with their life for daring to believe something else or offering proof that that the fact may not be a fact. I sat in a doctor’s office experiencing breathing problems so severe that the tests could not be completed. The machine said test inconclusive when the time ran out. He finally looked at me and said he knew I was suffering because he could seealll the signs but he has nothing to work with from the machine and he has to trust the machine. all THe machine was cleaned with alcohol which I was always sensitive to. I was there to see him because I had been on medical leave twice in a month and I could not breathe. Pefumes were my worse nightmares and I came to find out that asthama meds have both taste and smells. Pardon me if while I slowly dread each day I prefer to accept my lived experience and do not wish to have it repeated. Another doctor wanting to test my reactions pulled me in a room full of smells and when I forced her to let me go so I could find a corner away from the smells she said I had a panic attack because she did not smell anything! Forgive me if having to live the life of a guinea pig I do not want to become an unpaid lab rat. I am too busy trying to breathe which is not optional while living among people who obviously need their fragrances to deal with their lives. They will have to deal with the consequences of their actions and will unfortunately for a few of them come to understand that it isn’t in my head and neither is it an attempt to seek attention.


  12. An outstanding share! I’ve just forwarded this onto a co-worker
    who had been conducting a little homework on this.
    And he actually ordered me breakfast due to the fact that I found it for him…
    lol. So allow me to reword this…. Thanks for the meal!!

    But yeah, thanx for spending time to talk about this issue here on your site.


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