Whither multiple chemical sensitivities?

EDITORIAL Whither

Multiple

M

Chemical

ULTIP‘l,E Cl3E,MICAL SENSITMTIES (MC%) syndrome is reviewed by Dr Bruce A. IS-d in this issue of 1:Ihe.Jou.rnal. The concept of this entity as an environmentally caused collection of symptoms has encountered a rocky road on the way to general accc:ptancc 01 its existence, which has not occurred IO date. Beginning with the writings of Chicago allergist Thoeren Randolf, who was initially interestled in food allergy, the concept of altered respolnse to environmental exposure to chemicals and physical agents affecting many body systems has evolved. Patients with such complaints have been described as having 20th-century disease, total allergy syndrome, and general chemical hypersusceptibility. MCS syndrome has found its way into popular culture through the national television program “Northern Expo:sure” and in the movie “Safe.” Although this entity has been embraced by many popular writers in the lay media, it has not received a uniformly warm welcome from the medical community. Public dispute has been more the order of the day in the medical literature and in the political arena. The California Medical Association and, later, the American College of Physicians have both published formal position papers stating that no such disease entity exists.’ Other physicians have characterized the disorder as a psychiatric condition or a reflection of a subculture belief svstem.2,3 Clinicians who became involved in the use of sublingual challenge as a diagnostic method organized themselves as the American College of Environmental Medicine and set up a board to certify their competence in the management of such patients, whom they claim to diagnose and treat appropriately. Such specialists refer to themselves as clinical ecologists. Other physicians with .American

Journalof

Contact

Dermatitis,

Vol7,

No 4 (December),

Sensitivities?

an interest in such cases who do not subscribe to sublingual challenge testing for diagnosis, but who accept the environmental nature of the disorder, are found primarily in allergy, otolaryngology, and occupational medicine. Legal involvement in such matters has occurred as patients diagnosed with MCS syndrome, often referred to as victims, have sought compensation for their disability through workers’ compensation and disability insurance. These patients have found themselves ranged, with their treating physicians, against insurers and other members of the medical community who have cogently argued that their complaints were not environmentally related in the manner the patients and their physicians believed and that they were thus not entitled to receive disability benefits. In most instances, no benefits have been paid to such patients. Toxic tort legal cases have developed around the issue ofwhether persons exposed to environmental pollution associated with indoor ventilation problems in the newer airtight buildings, from exposure to toxic waste dumps, or as a result of military exposure to chemicals (eg, soldiers exposed to Agent Orange and soldiers complaining of being affected by Gulf War Syndrome) have developed symptoms and disabilities that could be characterized as MCS syndrome as a result of such exposure. Although such complaints are most popular in the United States and Canada, they are now being brought forward in Europe as well (J Wahlberg, personal communication, 1995). How does this matter find its way into the Journal as a feature article? One basis for this is the contention that persons who may fit into one of the broad case definitions that has been proposed may present themselves to dermatologists and those 1996: pp 199-201

199

200

with an interest in contact dermatitis, in particular, for assessment. Cutaneous complaints are not an infrequent complaint of such patients. It is also important to review this matter because the issue of allergy versus irritancy is germane to the possible understanding of at least some of these cases. One key feature of many of these patients is that they claim to experience adverse health effects from exposure to many environmental factors as varied as perfume, secondhand cigarette smoke, and even electrical fields from light fixtures, at extremely low levels of exposure. Our colleagues in allergy and clinical immunology report no evidence that type I hypersensitivity is a valid explanation for these health problems.4,5 Equally, type IV immune response is not arguably a mechanism that would explain what has been reported in such patients. Other investigators have tried to establish an association between altered cell-mediated or humorally mediated immune response aberration and MCS syndrome, although such conclusions are not consistent with the other data published.6,7 Proponents of MCS syndrome as a distinct separate clinical entity argue that the altered response may not be immunologic in the traditional sense, but more akin to an irritant response that is nonspecific, rather than being limited to a single allergen or closely related chemicalas as in an traditional allergic response. Recently, it has been suggested that the mechanism may be neurological rather than immunologic as a way to explain the lack of objective support for an immunologic mechanism. Excited skin syndrome* in the skin and reactive airways disease9 in the lungs, which have objective correlates, must be distinguished from what the proponents ofMCS syndrome as a distinct clinical entity have suggested as a basis for the diagnosis of MCS syndrome. There are patients within the general community who report persistent hyperirritability as a result of chronic contact dermatitis. There are persons who experience bronchial reactivity following sensitization by inhalation of allergens such as toluene diisocyanate. Many persons with allergic asthma experience bronchospasm when exposed to secondhand cigarette smoke, cold air, or airborne irritants. These recognized disorders, for which objective measures can document altered response, should not be confused with the entity that proponents of the MCS syndrome as a distinct disorder have been promoting.

EDITORIAL

All of these other entities are recognized and have a rational underpinning. What proponents of MCS syndrome are trying to do is ride on the coattails of these other established bona fide conditions. They argue that because these recognized disease entities can be categorized within the bounds of what they have called a new disease, this new disorder should be given credence. This line of thinking has been extended so far as to alter the name of the disorder again and refer to it not as multiple chemical sensitivities but rather chemical sensitivity and to endeavor to lump all persons who are chemically sensitive within the same category. As the readership of the Journal realizes, the public at large and individual patients, in particular, have great difficulty understanding the difference between allergy and irritancy. It is essential that our profession make every endeavor to educate our patients, our colleagues, and the public as to the difference between these two mechanisms. Similarly, we have a responsibility as physicians and biologically based scientists to point out unsubstantiated claims with respect to medical understanding if no objective evidence exists to support the claims. In many respects, the challenge facing us in understanding MCS syndrome is no different than Duhring and Brocq faced when they responded to claims regarding animal magnetism, which were made by Messmer in their day. Although there are patients who present with a constellation of symptoms that fit within one of several broad definitions put forward for MCS syndrome,‘“,” it is the clinician’s responsibility to objectively determine whether the findings can be adequately explained by categorizing the patients into a recognized diagnostic category or categories. This is essential if appropriate medical management is to be undertaken and the patient returned to health. If there is a distinct entity that is separate from other previously established diagnostic categories, dermatologists must be ardent and investigate these patients as carefully as possible so as to best characterize their condition. The results of such investigations of single cases or collections of cases must be published and submitted to collegial scrutiny if the disorder is to be established as a bona fide disease. To date, no such credible evidence has been published that would persuade objective medical scientists to accept the existence of MCS syndrome as a new, distinct entity requiring a new nosological

EDITORIAL

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categorization. It may never be so accepted. If such a separate condition with an environmental cause and a distinct pathophysiology truly does exist, its study and eventual effective management can only follow an objective understanding of the disorder. The readership has a responsibility to critically consider this matter and work with other physicians

to sort out what issue.

has become

a very contentious

James R. Nethercott, MD Department cfDermatolog University ofMa yland Baltimore, Mayland

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