As though contending with air pollution were not enough, there are individuals who suffer from what is called multiple chemical sensitivity (MCS). Most experts in environmental and occupational medicine restrict the diagnosis of this controversial condition to those who have developed an apparent supersensitivity to common environmental agents that cannot otherwise be readily explained by conventional medical or psychological diagnoses. Sometimes referred to as "environmental disease" or the twentieth-century syndrome, MCS is believed to be far from rare. The total number of sufferers in the United States is not known, but one recent study of patients visiting the occupational medicine clinics at two major medical centers suggested that the number of victims may be as high as 1 percent. While both sexes and any age group may be affected, the typical MCS sufferer is a white, middle-aged, middle- to upper-class woman.
Signs and symptoms of MCS include fatigue, dizziness, headache, memory loss, difficulty in concentrating, and mood alterations. Sufferers may also complain of rapid heartbeat, breathing difficulties, chest tightness, abdominal cramping, bloating, and diarrhea. Inflammation of the mucous membranes of the eyes, nose, and throat may also develop. Because the manifestations of MCS typically mimic those resulting from many other medical and emotional conditions, the diagnosis is often difficult to establish conclusively.
The list of substances that have been linked to MCS is awesome, and a detailed discussion of them would require a large volume in itself. The following are but a few of the more common categories of agents that have been implicated: Aliphatic hydrocarbons, found in glues and adhesives; aromatic hydrocarbons, which are in solvents and thinners such as benzene and toluene; halogenated hydrocarbons, contained in dyes, drugs, and disinfectants; chlorines, in bleaches and products in which bleaches are used, such as facial and toilet tissues, disposable diapers, tampons, and so forth; Phenols, found in preservatives, aerosol disinfectants, and oral hygiene products; formaldehyde, encountered in glues and resins, preservatives, chemical stabilizers, and permanent press and fireproof fabrics.
Persons affected by MCS are generally in good health until exposure to the particular environmental agent or type of environment that initiates the problem. At first the symptoms typically relate to the agent causing the problem. For example, the sensitive individual exposed to formaldehyde might complain of breathing difficulties and/or irritation of the eyes and skin. If exposure continues, lower concentrations of formaldehyde will trigger the same symptoms. Persistent exposure may ultimately give rise to what has been termed the "spreading phenomenon" in which the same symptoms once exclusively linked to the formaldehyde are now provoked by an evergrowing list of other substances or types of environments. These can include the scents of perfumes, cigarette smoke, new upholstery, carpets, pesticides, and news print, and may occur even in grocery store aisles or shopping malls. Curiously, this phenomenon can develop even when there has never been a problem with any of these items or places before. In general, MCS tends to be chronic, progressive, and severely debilitating. On rare occasions the condition has spontaneously disappeared as mysteriously as it appeared.
Experts disagree as to the underlying causes of MCS. Some theorize a hereditary basis. Others suggest that it is idiosyncratic in origin, that there is something peculiar to the makeup of the sufferer that is at fault. Still others contend that MCS is an allergic reaction. The latter maintain that the apparently nonspecific responses of victims to so many different environmental agents is in reality a consistent response to a single, as yet unidentified, ubiquitous allergen.
But whatever the precise cause(s) of MCS, diagnosing it is difficult. Unfortunately, no specific diagnostic laboratory tests are currently available. Allergists and specialists in both environmental medicine and occupational medicine generally agree on the following criteria for diagnosing MCS:
1. The symptoms must involve more than one organ system and must be aggravated by environmental agents or environments that do not affect the vast majority of the population.
2. The problem must have been present at least three months.
3. There must be no other medical or psychological conditions that would account for the patient's complaints.
In addition to a complete medical history and physical examination, a comprehensive workup for MCS might include allergy testing, dietary manipulation, pulmonary function studies, and smell acuity testing, depending on individual circumstances.
For the present, treatment of MCS basically consists of avoiding any known triggering factors and using medications to relieve symptoms. Suggested measures for improving the quality of the home environment are those recommended for dealing with traditional respiratory allergies and asthma. Perhaps the most encouraging bit of news for sufferers is the apparent growing recognition of MCS in the United States as a real entity that deserves additional intense investigation.
