A primer on Multiple Chemical Sensitivity for those unfamiliar with it

With the holiday season comes family gatherings, and with that — some challenges with MCS. Some of you family members that do not get MCS fully. MCS is an allergy but with one key difference: it does have have the pronounced IgE response that MDs normally see with allergies.

MCS is very much like a peanut allergy. “Oh, I cannot taste any peanuts in this food — so it is safe for Johnny to eat”. “Oh,  I can’t detect any smell so it’s safe to be around Mary” or worst (showing your ignorance) “It’s a psychological response to the smell” or better still “Johnny’s allergic response is psychological to the taste of peanuts and is attention seeking!”

MCS is not “smell base” – it is not multiple smell sensitivity or multiple fragrance sensitivity. It is sensitivity to certain modern synthetic chemicals. Often the chemicals are those used by the fragrance industry (and thus are not listed, or just listed as ‘fragrance’).

MCS impacts the brain

Recent studies have found that a MCS attack results in changes of SPECT brain scans:

MCS is in the brain, in the physical brain and not a psychological issue.


First, what is MCS symptoms – the department of Education disagrees with many MDs and believe that it is very real

From US Dept. of Education policy letter (2001)  (paper)

  • asthma or other breathing problems
  • autoimmune disorders
  • behavioral problems
  • bloating or other intestinal problems
  • cardiovascular irregularities
  • chronic exhaustion
  • disorientation or becoming “lost”
  • dizziness
  • dystonia (paralysis)
  • eye, nose and throat problems
  • fatigue and depression
  • flu-like symptoms
  • food allergies and intolerances
  • genitourinary problems
  • headaches
  • increased sensitivity to odors
  • inflammation
  • irritability
  • learning disabilities
  • mental confusion
  • movement disorders
  • muscle weakness and joint pains
  • numbness and tingling in limbs
  • persistent infections, especially yeast
  • persistent skin rashes and sores
  • seizure disorders
  • short or long term memory loss
  • visual disturbance

“Both the US Department of Housing and Urban Development (HUD) and the Social Security Administration (SSA) have recognized MCS, in some cases, as a disabling condition.”

The next question is to understand a bit about MCS — Studies from 1985 onwards has found that about 30% of people that have an allergic response (IgE response) also had coagulation triggered. If you look at most of the above symptoms, you will see that many of them are consistent with excessive coagulation happening: mental confusion, learning disability, irritability, etc

  • “This represents the first demonstration that cutaneous IgE-mediated allergic responses are associated with local activation of the intrinsic plasma coagulation-kinin pathways.” [1987]
  • “A patient presented with coagulation problems a few days after honeybee sting….She manifested signs of hypotension with disturbance of consciousness” [2004]

MCS can lead to transient ischemic attack and in rare cases to strokes, because of the massive coagulation produced. MCS attacks do not respond to anti-histamines (which is the normal treatment to allergies) because the IgE response is not dominant; coagulation is. Like with all allergies, if a person has had a recent attack, they may be hypersensitive for up to a year after a reaction. The “memory” of the reaction is carried in cells that have a life expectancy over 6 months. It is suspected that the epigenetics of a person changes due to the reaction.

If you are visiting with someone with MCS

There are simple rules that need to be followed precisely:

  1. Read this site on MCS
  2. Toss out every freshener in your house and car NOW.
  3. Toss out “Bounce” and every other type of dryer sheet and fabric care sheet
  4. Toss out everything that says “Unscented” – typically this means that a chemical has been added to mask the scent
  5. Do not use aftershave or perfume for at least 3 days before visiting
  6. Run your dryer on hot(not warm) for 3-6 cycles to drive out residue chemicals
  7. Use only Fragrance Free Laundry Liquid (for example biokleen) and wash the clothes that you are planning to use:
    1. With Laundry Liquid
    2. With vinegar
    3. With Laundry Liquid
    4. Store in a plastic bag until worn away from the rest of your clothes, ideally, outside.

If you cannot do this, then please contact the person and tell them you cannot be MCS safe and tell them what you are doing – assuming you are willing to do something more than just token steps (I would suggest it is said in an email — if it is not a long email describing many things, then a wise MCS person will simply say “forget it (and silently think: if they care so little for me — then the contact is not worth it)”.

There is no such thing as “I thought it would be ok” with MCS. If it is a family event, then the decisions become tough. If you are not willing to do it, then you need to decide: “Am I going to the event, or are they going to the event”  — it is an either/or.

If you decide to go, tell them and be frank and tell them you will not be MCS safe. End of story. End of visit for them likely. It is not a matter of them “inconveniencing you”, it’s a matter of putting their life at risk. You are giving a kid with a mild peanut allergy something that may be cross contaminated with peanuts (just a very little!) – you could be very luck and there is no response, mildly lucky and he has a mild reaction, or he could go into anaphylactic shock.