Idiopathic environmental intolerance is usually defined as the development of multiple symptoms that are attributed to exposure to any number of identifiable or unidentifiable chemical substances (inhaled, touched, or ingested) or exposure to electromagnetic fields in a person who has no detectable organ dysfunction or related physical abnormalities.
Idiopathic environmental intolerance is more common among women than men. In addition, 40% of people with chronic fatigue syndrome Chronic Fatigue Syndrome Chronic fatigue syndrome refers to long-standing severe and disabling fatigue without a proven physical or psychologic cause and without objective abnormalities found on physical examination... read more (also called systemic exertion intolerance disease or myalgic encephalitis) and 16% of people with fibromyalgia Fibromyalgia Fibromyalgia is characterized by poor sleep, fatigue, mental cloudiness, and widespread aching and stiffness in soft tissues, including muscles, tendons, and ligaments. Poor sleep, stress, strains... read more also have idiopathic environmental intolerance.
Some doctors consider idiopathic environmental intolerance to have a psychologic cause, probably a type of somatic symptom disorder Somatic Symptom Disorder Somatic symptom disorder is characterized by one or more chronic physical symptoms accompanied by significant and out-of-proportion levels of distress, worries, and difficulty in daily functioning... read more or an anxiety disorder similar to agoraphobia Agoraphobia Agoraphobia is fear or anxiety about being in situations or places with no way to escape easily or in which help might not be available if intense anxiety develops. These situations or places... read more (fear of going out in public) or a panic attack Panic Attacks and Panic Disorder A panic attack is a brief period of extreme distress, anxiety, or fear that begins suddenly and is accompanied by physical and/or emotional symptoms. Panic disorder involves recurrent panic... read more . Others believe the disorder may be a type of allergic reaction Allergic Reactions and Other Hypersensitivity Disorders read more . Various changes in the immune system may occur (although rarely), supporting the idea of an allergic reaction in some people. However, there is no consistent pattern of such changes among people who have this syndrome, and the cause remains unknown.
Some people start having symptoms after a single exposure to high levels of various toxic substances. People may attribute their symptoms to exposure to these substances, but evidence is usually lacking.
Symptoms may include a rapid heart rate, chest pain, sweating, shortness of breath, fatigue, flushing, dizziness, nausea, choking, trembling, numbness, coughing, hoarseness, and difficulty concentrating.
Commonly reported triggers for idiopathic environmental intolerance include
The diagnosis of idiopathic environmental intolerance is suspected if the symptoms
Recur after repeated exposure to the chemical substance
Recur after exposure to levels much lower than those that have been tolerated previously or that are commonly tolerated by others
Subside when the person leaves the offending environment
Develop in response to a wide variety of unrelated chemical substances
If a person's symptoms suggest idiopathic environmental intolerance, doctors try to identify possible causes of the symptoms, including other disorders. For example, symptoms could be caused by building-related illnesses Building-Related Illnesses Building-related illnesses are disorders that affect the lungs as well as other parts of the body and are caused by exposure to substances within modern airtight buildings. Building-related... read more , allergic disorders, some autoimmune disorders, or psychologic disorders. Depending on the person's symptoms and the findings during the physical examination, additional tests or assessments may be helpful. For example, blood and skin prick tests may be done to diagnose allergic disorders, or, if depression or anxiety seems possible, evaluation by a psychiatrist may help.
People may try avoiding the toxic substances thought to cause their symptoms. However, avoidance may be difficult because many of these substances are widespread. Also, the substances being avoided may not be the true cause of symptoms, so avoidance may be ineffective. People should avoid too much social isolation. Psychotherapy can sometimes be helpful. The aim of psychotherapy is not to convince people that the cause of idiopathic environmental intolerance is psychologic. The aim, rather, is to enable people to cope with their symptoms and improve their quality of life.