Multiple chemical sensitivity

Multiple chemical sensitivity (also known as MCS, formerly known as "20th Century Syndrome" or "Environmental illness") is a non-standard medical diagnosis for people with unexplained allergy-like symptoms who believe that several modern industrial or household chemicals are responsible. Conventional medicine does not recognize this diagnosis, because there is no definitive test, no plausible scientific mechanism, no reliable studies have demonstrated its claims, and because the symptoms are explainable by other means such as more conventional allergies, infectious disease, or psychological reaction to stress.

Allergist Theron G. Randolph (1906-1995) is generally credited with bringing this condition to public attention and it was he who first speculated that exposure to modern synthetic chemicals was the cause. Physicians who treat MCS generally identify themselves as "clinical ecologists", and many belong to the American Academy of Environmental Medicine, which Randolph founded in 1965 as the Society for Clinical Ecology.

People with MCS suffer widely assorted symptoms apparently on exposure to trace levels of environmental chemicals. No two MCS patients will experience exactly the same reactions to chemicals, but common symptoms include:

difficulty breathing, chest pains and asthma
skin irritation, contact dermatitis, and hives or other forms of skin rash
"brain fog" (short term memory loss, cognitive dysfunction) on exposure to triggers, headaches and migraines
digestive difficulties, nausea, indigestion/heartburn vomiting, diarrhea, and stomach cramps
multiple food intolerances, which may or may not be clinically identifiable (e.g., lactose intolerance, celiac disease)
joint and muscle pains
extreme fatigue, lethargy and lassitude
vertigo/dizziness
sensitivity to natural plant fragrance turpines
anaphylaxis and multiple organ failure in extreme cases

MCS patients often suffer from depression, anxiety and other psychological problems, leading some experts to believe that MCS is a physical manifestation of psychological disturbance (a psychosomatic illness) which should be treated with psychotherapy and tranquilisers. However, there is growing evidence that MCS is an over-reaction of the immune system related to synergistic chemical exposure, and a legitimate illness.

Conventional treatment approaches usually revolve around managing the potentially life-threatening symptoms and avoiding exposure. Like any allergy, MCS worsens gradually over time with repeated exposure to the chemical triggers, so many MCS patients go to extreme lengths to minimise this exposure. Enclosed air-conditioned buildings with a recycled air supply such as shopping centres, malls or large office buildings are particularly bad environments for the chemically-sensitive, who may have to avoid public gatherings entirely to avoid their illness being triggered.

Chemicals that generally need to be avoided include:

bleach, fabric softeners, wool-wash, and detergents
perfumes, air-fresheners and anything scented or perfumed
petrol or gasoline, diesel and exhaust fumes
pesticides, fertilisers, and garden chemicals
shampoos, hairsprays and personal care products
dishwashing liquid
most glues (including carpet glue), varnishes, polishes, paints, solvents and paint-thinners
petroleum-based products (petroleum jelly etc)

Many people with MCS also avoid exposure to inks, laser printers, and other potentially offgassing substances such as new furniture and plastic items.