Treatment Options in Multiple Chemical Sensitivity
by Gerald H. Ross, MD, CCFP, DIBEM, FAAEM
Environmental Health Center-Dallas, Dallas, TX

Source: This article was originally published in 1992 in Toxicology and Industrial Health, 8(4), 87-94. It is part of the Proceedings of the Multiple Chemical Sensitivity Workshop, Washington, D.C., of the Association of Occupations and Environmental Clinics (AOEC), with support from the Agency for Toxic Sensitivities and Disease Registry (ATSDR).

Correspondence: Address all correspondence to Dr. Gerald H. Ross, Environmental Health Center-Dallas, 8345 Walnut Hill Lane, Suite 205, Dallas, TX 75231.

Multiple chemical sensitivities (MCS), a condition that probably has been present for hundreds of years in various manifestations, is gaining increasing recognition in medicine (Hileman, 1991). At the same time, the prevalence of classical allergy like asthma and hay fever is growing, and paralleling this is an increase of symptoms that some patients exhibit from exposure to commonly-encountered chemical substances. Simply defined, MCS is a significant intolerance to low-dose components in the patientís personal environment, which most other people tolerate quite well.

Because of the complex nature of this condition, it is important to keep in mind the concept of total load or the total environment. This involves the complex interplay of genetic endowment, nutritional status, emotional stress, and exposure to foods, chemicals, microbes, inhalants, and even electromagnetic fields. How health is expressed is obviously a function of the cumulative effect of these factors on the patient.

Treatment options for MCS center around education, avoidance of allergens (including those in air, food, water), environmental clean-up procedures, rotational diets, enhancement of nutritional status, immunotherapy, immune stimulation, detoxification where appropriate, and addressing the patientís social and emotional health. In addition, he emerging awareness remains that electromagnetic fields may play a significant role in certain situations (Fitzgerald, 1990). It is vital to establish a relationship whereby patients feel that physicians take their complaints (though perhaps myriad and long standing) seriously and in an atmosphere of mutual respect and trust. Within such a context, patients will more readily accept education about things they potentially can do to help themselves.


Surely the basis of treatment for any allergic or sensitivity problem is to avoid the sensitizing agent. This can be done whether the primary problem is in air, food, water, or physical surroundings, and it may even apply to electromagnetic fields to a certain extent.


Because MCS patients frequently have wide varieties of allergies or sensitivities, they usually benefit from programs that minimize their contact with potentially sensitizing substances. Glass-bottled spring water is frequently helpful because it is much purer and does not contain the chlorine, fluorine, and other contaminants usually found in domestic drinking water supplies. Unfortunately, water bottled in plastic containers may pick up the phthalate, solvents, or plasticizers used to manufacture the plastic itself (Kailin and Brooks, 1963); for this reason the author recommends water bottled in glass.

One of the largest and best-recognized sources of contact we have with chemical contaminants is our food supply (Davies, 1986), which frequently contains pesticides and other chemical residues potentially harmful to everyoneís health, and especially to persons with chemical sensitivity. Consequently, MCS patients often do much better clinically by consuming organically grown, less chemically contaminated food products.

Because of the massive incidence of indoor air pollution, which is often 100 times that of outdoor air (Nero, 1988; NRC, 1981), air-filtration devices that remove both particulate and chemical substances from breathable indoor air usually benefit MCS patients considerably. In addition, steps to minimize indoor pollution by removing carpeting and combustion products from the home (such as natural gas, heating oil, or wood-burning stoves) usually bring about substantial improvements as well (Barron, 1990; Drerup et al., 1990).

Indoor air pollution is generally lower in homes that have hardwood or tile floors, with natural wood rather than fiber board, plywood, or other pressed-wood products that contain substantial amounts of glues, solvents, and other chemicals (including formaldehyde). The latter will offgas and contaminate indoor environments for months or even years (Levin, 1989). Similarly, synthetic fabrics and other materials made from petroleum will slowly offgas volatile organic compounds (VOCs) and other chemical substances used in their manufacture, thus adding to the total load of indoor pollution. These latter substances frequently trigger symptoms and health deterioration in patients with MCS. An intelligent program of minimizing this kind of exposure usually has substantial therapeutic benefit for these patients.


Shandra (1980), a widely recognized international nutrition expert, has called undernutrition the most frequent cause of immunodeficiency. Because human enzymatic, metabolic, and detoxification pathways are largely dependant on adequate vitamins, minerals, and other essential co-factors, the nutritional status of patients with MCS is of obvious importance and concern (Jacoby, 1980). A survey of more than 330 patients at the Environmental Health Center-Dallas showed widespread vitamin deficiencies (including a B6 deficiency in almost 58% of these patients) even in the presence of oral supplementation (Ross et al., 1990). A rotational diet is one way to minimize exposure to food substances to which the patient may be sensitive, and the diet can be readily designed by competent personnel within the context of nutritional adequacy (Radcliffe, 1987). A rotational diet does not repeat the same food or beverage item within the rotational cycle, and such diets can be constructed in several ways. To illustrate a 4-day, monorotational diet (one food per meal): On Day 1, the patient might consume eggs for breakfast and would not again consume any egg products until the morning of Day 5, thereby minimizing contact with potentially sensitizing foods. A rotational diet is relatively simple to institute, even before the foods to which the patient is actually sensitive are known. Such a diet minimizes over-exposure to any foods, and when properly constructed, can provide good nutritional adequacy and wide variety.

Patients with MCS are known to have a higher likelihood of nutritional imbalances (Ross et al., 1989), especially magnesium deficiency (Rea et al., 1987a). Because many patients with MCS seem to be nutrient deficient despite oral supplementation, intravenous infusions of certain vitamins and minerals (especially vitamin C and the B vitamins, magnesium, and trace minerals) can have excellent therapeutic benefits. The exact mechanism of benefit is not known but may be through enhancing both immune function and detoxication pathways.

The Nova Scotia Environmental Medicine Clinic is currently engaged in a collaborative pilot study with the government of Nova Scotia in Canada on intravenous infusion of nutrients, including magnesium, for patients with chronic fatigue syndrome. In the authorís experience, these patients also frequently have intracellular magnesium deficits.

Candida Sensitivity.
One aspect of the total-load or the total-environment concept might include the possibility of Candida sensitivity or overgrowth (Kroker, 1987). Although this issue is controversial, many of the authorís patients with MCS have substantial elevations of antibodies against Candida and may have had recurring vaginal or oral yeast infections. An anticandida program involving dietary modification, nutritional support, the replenishment of healthy gut flora, and possibly an antifungal medication may prove very beneficial. Moreover, present knowledge about the potential adverse effects of Candida on susceptible individuals appears far from complete. It seems reasonable to keep an open mind on this topic because the author has seen many patients who benefitted from such an approach, within a context of evaluating and lowering the total load.
Intradermal and Sublingual Testing. A vital question remains: How does one evaluate and confirm chemical sensitivity? As in all medicine, initial reliance is primarily on history. Two main types of confirmatory testing, involving intradermal and inhalation challenge, are currently available. Most patients with a history of MCS have widespread sensitivities to chemicals, foods, and, to a lesser extent, inhalants (Rea and Ross, 1989). The testing antigens used for intradermal food testing at the Environmental Health Center-Dallas are prepared from organically grown products, with no preservatives in the vaccines. This is in distinction to most testing antigens on the commercial market, which have either phenol or glycerine as stabilizers. Many patients with MCS cannot tolerate antigens that contain these substances for either testing or treatment. A variety of well-known, skin-testing techniques are available, including scratch or prick testing. Serial-dilution, end-point titration (SDET) and provocation-neutralization also give reliable data for use in a treatment program (King and King, 1990).

With provocation-neutralization, potential treatment vaccines may be drawn up for foods, chemicals, inhalants, microbial substances (like mixed respiratory vaccine and fluogen), and individual bacteria produced from autogenous vaccines; the latter are particularly helpful in patients with chronic rhinitis or sinusitis.

Sensitivity to a variety of chemicals may also be tested directly in the same way. Subsequent immunotherapy treatment with very low-dose, subcutaneous or sublingual vaccines can proceed in conjunction with avoidance of the offending agent (Scadding and Brostoff, 1986). Testing and treatment are also possible with neutralizing doses to neurotransmitters, like serotonin, dopamine, methacholine and others, which can produce substantial improvement in the patientís symptomatology. Intradermal testing involves not only evaluating the skin whealing response but also assessing symptoms and signs that may be produced from the testing itself. Sublingual testing, which relies almost exclusively on symptoms or signs, can nevertheless be a valuable testing technique.

Inhalation. One of the most scientifically rigorous evaluations of chemical sensitivity is specific challenge with low-dose chemical exposures. These take place inside in an enclosed glass and anodized-aluminum booth, under controlled circumstances (Rea et al., 1990). When done properly, these can help determine whether the patient is sensitive to a variety of chemical substances. Appropriate dilutions of chemicals are vaporized in the booth to achieve concentrations that are below odor thresholds and that approximate levels found in everyday settings (Rea et al., 1990). These tests are performed on a double-blind basis, using placebos of water or saline. The booth is evacuated and washed after each challenge to prevent any potential contamination. The absence of intake pipes or tubes that direct gas into the booth also prevents potential contamination and subsequent invalidation of subsequent tests at a later date. Chemical testing performed in such a booth must be done with the patients in the deadapted state for reliable results (Rea et al., 1990).

The ideal location for this type of low dow-dose, chemical challenge is a hospital-based, environmental control unit (ECU) (Sprague, 1987) in which the patient is housed in a very clean environment for several days before testing begins. The principles of total load and deadaption must be understood and followed with low-dose, inhaled, challenge testing, because incidental outpatient exposures to perfume, traffic exhaust, cigarette smoke, or other substances may trigger delayed responses that will cause inconsistent results.

Transfer Factor. Another potential treatment for patients with MCS is immune stimulation, especially in view of the frequent occurrence of immunosuppression with this illness (Levin and Byers, 1987). The use of transfer factor may prove very helpful in these cases (Youdim et al., 1991). Transfer factor is an extract of white blood cells with known immune-stimulating properties. It is especially helpful in cases of leukopenia or in reduced leukocyte-killing capacity, which may contribute to recurring infections.

Pupilography. An additional method being developed to evaluate patients with MCS is the assessment of autonomic nervous function by pupilography (Shirakawa et al., 1992). Hamamatsu Photonics in Japan, in cooperation with the Department of Ophthalmology at Kitasato University, has developed a sophisticated optical device called the binocular iriscorder, that scans the eye surface in the infrared spectrum and measures the pupilographic response to a specific light stimulus by very precise, computerized measurements. These are then compared with a standard reference range.

The change in pupil size, velocity of contraction and dilation, recovery time, and other parameters are measured in milliseconds following the light stimulus. These measurements are usually quite stable in each individual, with a slight diurnal variation. Patients with MCS have frequent deviations from baseline and exhibit considerable instability of autonomic function, usually in a sympatholytic pattern (Shirakawa et al., 1992). Many patients, whom the author has tested in blind, intradermal challenges with agents to which the patient is known to be sensitive, show distorted autonomic stability. Further research with this computerized analysis is pending.

Posturography. Another technique for evaluating patients with MCS is posturography testing, which essentially evaluates the neurologic integration of the nervous input from the eyes, ears, and peripheral nervous system by computerized methodology. Frequently, the author finds disorders of balance in patients with chemical sensitivity, and especially patients with histories of significant chemical exposures. When these patients undergo detoxification programs to enhance metabolism and the elimination of toxic chemical substances from their bodies, substantially improved measurements of these specific, neurologic balance function usually result.

Adipose and Nerve Tissue
Toxic chemical substances may be stored for long periods in adipose and nerve tissue; many xenobiotics are direct neurotoxins (Seba et al., 1987). Indeed, DDT-type compounds and many others are often found in adipose tissue at much higher levels than would be found in blood under steady-state conditions. Certain individuals appear to have an impaired ability to detoxify effectively some of these exogenous substances. The chemicals may then build up over long periods following repeated exposures, especially in industrial settings (Seba et al., 1987). Levels of potentially toxic chemical substances at 10-40 times the population average, or even greater, are not unusual in MCS patients. With such toxic loads, it is perhaps not surprising that patients are unwell with various neurologic and other symptoms.

Detoxification. One method that is gaining considerable interest for reducing this total toxic load is a detoxification program using an integrated regimen of graduated exercise; nutrient replacement; and sauna-chamber, heat depuration therapy (Schnare et al., 1982). The heat chamber at the Environmental Health Center-Dallas is built with ceramic tile on all inside surfaces and untreated wooden benches; it uses relatively low temperatures, in the range of 140° F. Patients first exercise and then spend time in the sauna to induce profuse perspiration. Under these conditions, stored xenobiotics appear to mobilize substantially (Schnare et al., 1982) and can then be metabolized, primarily through the liver and the gut, but also through the breath, urine, and perspiration. The clearance rate of stored xenobiotics from the body may be quite variable, and the authorís experience shows that styrene and chloroform come out most easily. 1,1,1-Trichloroethane is ubiquitous and seems to be the most difficult to clear (Rea et al., 1987b). If, however, such a detoxification program proceeds too quickly, the patient may worsen for a time, usually in conjunction with a rise in liver transaminases, which suggests a significant strain on hepatic function. With caution, however, these xenobiotics can be substantially reduced in MCS patients, usually with marked improvement in the patientís overall chemical sensitivity and general health (Rea et al., 1987b).

Another area of growing interest and potential treatment is the controversial issue of amalgams and their adverse consequences on health. The television program 60 Minutes reported on the hazards of silver/mercury tooth fillings and raised many questions about the safety of this heretofore well-accepted dental material. Although this subject is controversial and consensus is lacking, sensitization to mercury is a real phenomenon. Removing amalgams is an option that certainly requires investigation, especially for chemically sensitive patients.
                    The essential features of treatment for chemical sensitivity are the following:

                    (1) Encouraging the provision of clean air, food, water, and surroundings.

                    (2) Identifying substances to which the patient is sensitive, with subsequent

                            (A) enhanced avoidance, or

                            (B) specific immunotherapy to reduce the patientís reactivity to those substances.

                    (3) Assessing and enhancing the patientís nutritional status to maximize the bodyís ability to detoxify and to
                          minimize the free-radical production and oxidative stress xenobiotics.

                    (4) Addressing concurrent problems such as infections, immunosuppression, and other medical conditions in an
                         appropriate fashion.

                    (5) Evaluating the patientís psychologic status and addressing any social and emotional problems in a
                          compassionate manner.

The author believes that multiple chemical sensitivity is a real condition with documented physiologic abnormalities. It is not a functional or psychologic illness or a belief system of the patient. Second, this condition is diagnosable and treatable by various means. These treatment options not only make common sense but usually result in significant improvement for these unfortunate patients, who deserve the very best effort of their health care providers.
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