Multiple Chemical Sensitivity (MCS)

What is multiple chemical sensitivity (MCS)?

Multiple chemical sensitivity (MCS), also called chemical injury, chemical sensitivity, environmental illness (EI), sick building syndrome, idiopathic environmental intolerance, and multiple allergy, is a condition that causes a severe allergy-like, sensitivity reaction to many types of pollutants. Some of these pollutants include perfumes, petrol, diesel, smoke, solvents, volatile organic compounds (VOC), and other chemicals. People with this condition also sometimes have sensitivities to pollen, dust mites, and pet fur or dander. 
The exact cause of MCS is not known. It is not considered a true allergy because why and how it happens is not well understood. To be diagnosed with MCS, the person must meet the following criteria:
  • Sensitivity/allergy-like reaction to low levels or irritants/toxicants/triggers
  • The person is affected by multiple different triggers
  • Experiencing symptoms even when the levels of triggers are low
  • Improvement when triggers are absent
  • The symptoms are reproducible with exposure to the same triggers
  • The problem is chronic, not a one-time experience. 
  • The symptoms involve multiple organs
*Symptoms, triggers, and their severity can vary from person to person. There is currently not much known about MCS.*
MCS may also go by many other names, such as:
  • Bioecologic illness
  • Cerebral allergy
  • Chemical intolerance
  • Ecologic illness
  • Immunotoxic syndrome
  • Total allergy
  • Toxic encephalopathy
  • Toxic injury
  • Toxicant induced loss of tolerance
  • Twentieth century illness
  • Universal reactor
Risk factors
  • Exposure to chemicals or pollutants that may trigger symptoms 
There are no definitive tests used to diagnose MCS. Diagnosis will likely be made based off one’s signs, symptoms, and precipitating factors.
There have been no proven effective treatments for MCS. Potential treatment options for MCS include:
  • Avoiding triggers to the best of one’s ability without causing social isolation
  • Antidepressant medications
  • Anti-anxiety medications
  • Obtaining an adequate amount of sleep
  • Relaxation techniques
  • In 2009, studies suggested that about 10 million Americans were suffering from MCS. 
  • Approximately 11-16% of the American population suffer from MCS
about multiple chemical sensitivity (MCS)

  • "What Is Multiple Chemical Sensitivity (MCS)." Multiple Chemical Sensitivity. Word Press, 2017. Web. 22 Nov. 2017. 
  • “Multiple Chemical Sensitivity.” WebMD, n.d. Web. 22 Nov. 2017. 
  • “Multiple Chemical Sensitivity Syndrome.” American Academy of Family Physicians. American Family Physician. 01 Sep. 1998. Web. 22 Nov. 2017.
  • “Prevalence of MCS.” The Chemical Sensitivity Foundation, n.d. Web. 22 Nov. 2017.
  • “Multiple Chemical Sensitivity (MCS).” The Environmental Illness Resource, 13 Jun. 2017. Web. 22 Nov. 2017. 
  • “Environmental Illness-Topic Overview.” WebMD, n.d. Web. 22 Nov. 2017. 
  • “What Is Environmental Illness?” Rocky Mountain Environmental Health Association, 05 Mar. 2017. Web. 22 Nov. 2017. 


What may trigger allergies and/or asthma varies from person to person, so it is imperative that people are aware of what their triggers are. Both reactions can range from mild to severe. Learning how to reduce exposure and how to manage symptoms will benefit individuals suffering from these conditions.
asthma and allergy awareness month


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