History and Clinical Presentation of the Chemically Sensitive Patient
by Gerald H. Ross, MD, CCFP, DIBEM, FAAEM

Environmental Health Center-Dallas, Texas

Source: This article is exerpted from the original published in 1992 in Toxicology and Industrial Health, 8(4), 21-28. The graphics included in the original publication are not presented here. They can be obtained via a written request. Address all requests/ correspondence to Dr. Gerald H. Ross, Environmental Health Center-Dallas, 8345 Walnut Hill Lane, Suite 205, Dallas, TX 75231.


Early in 1991, an advertisement illustrating the growing public awareness of potential problems with sensitivities to common substances around us appeared on the back cover of Good Housekeeping magazine. It showed a little girlís party dress on a hanger, obviously not being used, with the title, "How can such a nice dress be so irritating?" The ad explained the benefits of a new laundry product made without perfumes or dyes and implied the new laundry liquid would not leave chemical residues in the fabric that would subsequently irritate little girlsí sensitive skin. It is doubtful that such an ad, expressing concern about the chemical residues we are all exposed to in modern society, would have appeared ten years ago,. This advertisement may be a sign of the times. Chemical Sensitivity Chemical sensitivity is an abnormal state of health characterized by intensified and adverse responses to components found in food, air, water, or physical surroundings of the patientís environment (Hileman, 1991). The provoked symptoms or signs may be chronic, relapsing, or multisystem and are triggered by levels of exposure that are generally well tolerated by most people. The diagnosis is suspected on the basis of history and physical examination, and the condition may be confirmed by removing the offending agents and rechallenging patients under properly controlled conditions. The clearing or improvement of symptoms or signs by removing the suspected substances and the recurrence or worsening after specific, low-level challenge is highly indicative of environmental hypersensitivity and, in this context, chemical sensitivity. This definition is very similar to that proposed by Ashford and Miller (1989) in their report to the State of New Jersey and in their subsequent book (Ashford and Miller, 1991).

 If we consider a patientís total environment as a complex interplay of genetic endowment; nutritional status; emotional stress; and exposure to foods, chemicals, microbes, inhalants, and even electromagnetic fields, then the expression of health is a function of the interplay of those factors and their effect on the patient (Randolph, 1962). Also necessary and important is the concept frequently used in environmental medicine of biochemical individuality, which is essentially the metabolic uniqueness that characterizes each person. No two individuals are identical in how they respond to a stressor (Calabrese, 1984). Although basic common sense and the lessons leamed in medical school point to the concept of metabolic uniqueness, it is often overlooked in medical practice. For example, probably 10% of the population are slow metabolizers of the drug debrisoquine (Brostoff, 1987). The genetic polymorphism that determines fast or slow metabolism may be an important factor in expressing susceptibility to certain diseases or reactions to toxic environmental chemicals. Thus, the genetic variation (predisposition), phenylketonuria (PKU), sets the stage for severe problems if too much phenylalanine (stressor) is taken in the diet. Similarly, food-sensitive migraine patients frequently have phenylsulfotransferase deficiencies that may contribute to the onset of headaches when certain foods are consumed (Brostoft, 1987). Individually, many persons may have inborn variations of metabolism that predispose them to potential problems with metabolism or detoxication of substances in the chemical environment (Jacoby, 1980).

Randolph (1980), in his excellent book, An Alternate Approach to Allergies, describes the chemically sensitive patient: "Typically, however, patients have been polysymptomatic; that is, they have a long history of many problems, physical and mental, which have left them in a general state of misery. The more symptoms they accumulated, the less the doctors believed their complaints." All too often, once the physician reaches the end of the diagnostic repertoire for classifying a patientís complaints, the patient tends to be classified (by default) as having a functional or psychologic origin for confusing symptoms. This difficulty with diagnosis involving complex symptoms does not necessarily indicate a problem patient but perhaps a physician who lacks the proper knowledge to make a correct diagnosis. Survey of Chemically Sensitive Patients Future discussions of patients with multiple chemical sensitivity (MCS) may be aided by statistical data from a large survey, conducted by the staff at the Environmental Health Center in Dallas, Texas, of more than 200 consecutive patients being investigated and treated in the Environmental Control Unit (Sprague, 1987). The Environmental Health Center is a multidisciplinary facility of physicians, psychologists, research scientists, and support staff who have extensive experience with patients referred from around the country with symptoms of chemical sensitivity. This clinic is specially constructed with porcelain-on-steel walls and ceilings, terzazzo tile floors, extensive air-filtration systems, and other controls to minimize indoor air pollution and maximize the likelihood of patients being in a baseline state before appropriate investigation and treatment of allergies or chemical sensitivities.

Age distribution of the patients is shown in Figure 1. Consistent with findings of other studies, about three-quarters of these patients are women. Most present for evaluation in their 20s, 30s, or 40s but report that symptoms atributable to environmental problems first started at a much earlier age, even in the teenage years and earlier (Figure 2). Although disturbing in some respects, this information is encouraging because it raises the possibility of early intervention to prevent progression of this condition. The number of physicians previously seen by these patients varied, but it was not unusual for a patient to have consulted as many as 20 doctors in trying to find answers for their unusual health problems Figure 3). The education level in this group tended to be rather high; many were college educated Figure 4). These patients represented a wide spectrum of occupations and trades, including business, sales, labor, law, teaching, technical trades, other professionals, clergy, physicians, other medical personnel, clerical workers, homemakers, artists, students, and engineers (Figures 5a and 5b).

Typically, the family history in many of these patients was positive for classical allergy, and the likelihood of migraine headaches, alcoholism, thyroid dysfunction, collagen vascular diseases, or psychiatric diagnoses in the family appeared high. A careful history of these patients might reveal a significant deterioration in their health after some identifiable event, such as redecorating the house, the arrival of a new baby, prolonged recovery from the flu, moving into a new building, or exposure to pesticides.

The most frequent complaints in this survey of patients ranged from headache, fatigue, confusion, depression, shortness of breath, and arthralgia, to myalgia, nausea, dizziness, memory problems, gastrointestinal symptoms, or respiratory symptoms (Figures 6a and 6b). Neurologic symptoms, including migraine, poor memory, confusional states or "brain fag," tremor, weakness, and numbness, seemed to top the list. Patients frequently reported anxiety, depression, irritability, and dizziness, and some also reported that noise particularly irritated them. On occasion, they reported being tearful, with a higher-than-usual incidence of addiction. A frustrating aspect for these patients (and their doctors) was a lack of consistent and pathognomonic physical indicators of MCS. Patients sometimes said, "I feel so awful, that if one more person tells me how good I look, Iíll scream!" Common Characteristics Despite the lack of universally consistent physical findings in chemically sensitive patients, certain characteristics are seen more often than not. Although anecdotal, it may help physicians interested in MCS to know that chemically sensitive patients are more likely to have unstable physical balance, to be easily confused, and to have poor memory that can be measured objectively on neurologic evaluation (Rea, 1984). Frequently, they complain of cold hands and feet, possibly from autonomic instability and vascular spasms. They are much more likely to be underweight than overweight. The women may have a history of fibrocystic breast disease or thyroid dysfunction, and many have coated or geographic tongues and develop aphthous ulcers after eating certain foods. Children have a high incidence of learning disabilities or hyperactivity, often get very sleepy after lunch, and may he quite erratic in their school work. Patients with chemical sensitivities often have food cravings, histories of food and other addictions, and may experience withdrawal symptoms when they go without certain foods. Children especially may exhibit Jekyll-and-Hyde-type sudden personality or mood changes (Rapp, 1991).

Chemically sensitive patients may be diagnosed objectively, however, and this is perhaps best demonstrated on double-blind, placebo-controlled, low-dose chemical challenges, under environmentally controlled conditions (Rea, 1990a).

Summary Although no one has all the answers to the mystery of chemical sensitivity, the reality of this condition, most recently called multiple chemical sensitivities, is not in doubt. Evidence is increasing of its possible physiologic mechanisms, which will be discussed later in this volume. From the evidence and from personal and professional experience, the author believes that chemical sensitivity is not a diagnosis of exclusion and that fixed-name diseases may have environmental triggers or complicating factors (Rea, 1990b). With appropriate preparation and environmental controls, MCS can be investigated and diagnosed in a scientific and reproducible manner. References

                    Ashford, N.A., & Miller, C. S. (1989, Dec.). Chemical Sensitivity. A Report to the New Jersey State
                    Department of Health.

Ashford, N.A., & Miller, C. S. (1991). Chemical exposuresóLow levels and high stakes. New York: Van Nostrand Reinhold, New York.
Brostoff, J. (1987). Mechanisms. In J. Brostoff and S. Challacombe, (Eds.), Food allergy and intolerance (pp. 443-455). Philadelphia: Bailliere Tindall/W.B. Saunders. Calabrese, E. J. (1984). Ecogenetics: Genetic variation in susceptibility to environmental agents. New York: Wiley.

Hileman, B. (1991). Multiple chemical sensitivities. Chem. Engin. News, 69(20):26-42.

  Jacoby, W. B. (1980). Detoxication enzymes. In W.B. Jacoby (Ed.), Enzymatic basis of detoxication, Vol 1 (pp. 1-6). New York: Academic Press.   Randolph, T. G. (1980). An alternate approach to allergies (rev. ed.). New York: Harper and Row.

Rapp, D. (1991). Is This Your Child? New York: William Morrow and Co.

Rea, W. J., Butler, J. R., Laseter, J. L., & DeLeon. I. R. (1984). Pesticides and brain function changes in a controlled environment. Clin. Ecol., 2(3), 145-150.

  Rea, W. J., Ross, G. H., Johnson, A.R., et al. (1990a). Confirmation of chemical sensitivity by means of double-blind inhalant challenge of toxic volatile chemicals. Clin. Ecol., 6(3), 113-118.   Rea, W. J., Ross, G. H., Johnson, A. R., Smiley, R. E., & Fenyves, E. J. (1990b). Chemical sensitivity in physicians. Clin. Ecol. 6(4):135-141.   Sprague, D. (1987). The concept of an environmental unit. In J. Brostoff and S. Challacombe (Eds.). Food allergy and intolerance (pp. 947-960). Philadelphia: Bailliere Tindall/W.B. Saunders.  


To buy products for the chemically sensitive see http://www.aehf.com.
For more information on medical treatment see http://www.ehcd.com.
For more articles on the relationship of health and disease to environmental factors, see the list of available articles and other information available here.