Chemical sensitivities

Chemical sensitivities refers to symptoms are being experienced in response to exposure to certain chemicals, which would not trigger adverse symptoms for most people, at least at low concentrations.

Common triggers for chemical sensitivities include pesticides, perfume and petrochemicals, like petrol and paint. Natural irritants like mold and wood-fire smoke are also common triggers.

Symptoms of chemical sensitivities can include: headache, migraine, cognitive impairment, dizziness, fatigue, nausea, vomiting, cardiac abnormalities, skin rashes, asthma, and anaphylaxis.

New chemical sensitivities are recognized as a common symptom of ME/CFS, and some people react to so many substances that they also meet the diagnostic criteria for Multiple Chemical Sensitivity (MCS).

Symptom recognition

 * The International Consensus Criteria lists sensitivities to food, medications, odors or chemicals as an optional criteria for diagnosis, under the section C. Immune, gastro-intestinal and genitourinary Impairments.
 * 2018, The Centers for Disease Control and Prevention note ME/CFS patients can have "allergies and sensitivities to foods, odors, chemicals, or noise."
 * The Canadian Consensus Criteria for ME/CFS (2003) includes "new sensitivities to food, medications and/or chemicals" asan optional immune system symptom of ME/CFS.