Grace Ziem, M.D.,DR. P.H.
ALLERGIES AND CHEMICAL REACTIONS
Allergies have been
defined by physicians as reactions to substances by formation of rapid-acting
antibodies known as IgE, which is immunoglobulin E. Persons who have allergies
to substances like mold, pollen, dander, or dust often have this form of
reaction. Molds release volatile organic compounds that are similar to those
found in sick buildings and these can also cause reactions to molds that are
not what physicians describe as a true allergy. Molds can also release
mycotoxins, causing a toxic type of reaction, which is not an allergy. Of
course, an individual can react to mold with a combination of these types of
reactions. There are also certain chemicals that induce the production of IgE antibodies
and these are considered chemical allergens. Examples include formaldehyde,
isocyanates, and a limited number of other chemicals. Formaldehyde and
isocyanates are also potent irritants and can irritate the respiratory tract
without a true allergy reaction, in other words, without the presence of IgE
antibodies. IgE antibodies are typically formed to a particular substance or
group of substances. For example, there are many isocyanates that have a very
similar chemical structure to each other, and a person who has developed IgE
antibodies to one isocyanate may also have an IgE reaction to other isocyanates.
Many chemical
reactions however, do not involve the production of IgE antibodies and
therefore are not strictly speaking an allergy. Individuals who have become
chronically ill or who have frequent symptoms in the presence of various
chemical pollutants often have increased inflammation of their respiratory
tract. Chemicals that are irritants can exacerbate this inflammation, causing a
chemical reaction of illness symptoms, which is not an allergy because it does
not involve the production of antibodies. This does not make it less serious or
less real, but simply means that the body is reacting in a different manner.
Virtually all petrochemical substances are irritants. There are other
chemicals, which are not derived from petroleum or coal, which are also
irritants. Chlorine, products containing chlorine, and ammonia are examples of
potent irritants, which are not derived from petroleum or~ coal but are still
irritating to the respiratory tract. It is important to remember that there is
no barrier between the nose and the brain. This is because the nerve involved
in detecting smell, the olfactory nerve, is actually a direct extension of the
brain with nerve endings in the lining of the nose. Studies have documented
that chemicals and even toxic metals are capable of entering the brain by
passing along the olfactory nerve. Thus, the concept of a blood brain barrier
that helps to limit substances entering the brain does not apply when chemicals
are breathed into the nose. This is one reason that reactions to chemicals can
occur so rapidly. There are other ways in which an individual can react to
chemicals. The detoxification system may be impaired, occasionally genetically
but more commonly because of past toxic exposure, and the individual may have
more difficulty detoxifying. This can cause them to have reactions at dosage
levels that would be less of a problem for healthy individuals with normal detoxification.
It is important to recall that the vast majority of pharmaceutical agents are
derived from petrochemicals and must be detoxified by the body using the
detoxification system. Therefore, an individual who has impaired detoxification
may have more difficulty tolerating medications, particularly those that share
a detoxification pathway that has become deficient (for example, from a past
significant chemical exposure). Toxic exposure of certain chemicals can cause a
delayed immune reaction, which is not referred to as an allergy since it does
not involve IgE, but does involve the immune system. This is another mechanism
of chemical intolerance. Another mechanism, which has been
scientificallydocumented, is a sensitizing process that involves the brain,
referred to as neural sensitization. This renders the brain more susceptible to
toxic exposure. Some individuals may also have brain changes referred to by
scientists as kindling or near kindling. This involves a brain response in
which the person has seizures or seizure-like activity following exposure to
chemicals. It has also been demonstrated that individuals who have toxic
exposure can have reduced blood supply to the brain. When this is present, the
individuals may have chronic difficulty with thinking, memory, concentrating,
and other brain functions. Challenge studies show that individuals like this
have a significant further drop in the blood supply to their brain when they
have even modest exposures such as a whiff of perfume, air fresheners, and other
substances which by history are known to affect individuals with chemical
intolerance, sometimes referred to as heightened sensitivity to chemicals. The
mechanisms of chemical intolerance can cause relatively rapid reaction to
pollutants, sometimes only delayed reactions, and often reactions which have
certain symptoms present more quickly and other symptoms developing later. For
example, an individual may experience headache and/or irritation of the nose,
throat, or chest as a more prompt symptom. This inflammation can then cause
release into the blood stream of substances which increase fatigue and aching,
which are often more delayed effects of an exposure. It is important that
people understand that chemical intolerances are a real medical problem, which
has been supported by a significant amount of research and scientific study.
Multiple studies confirm that reducing exposure in the environment, which
includes but is not limited to leaving an area when symptoms occur, is
important for long term well being. There are four studies in the medical
literature which confirm that reduced exposure is a major factor in the
long-term outcome of patients who have become chemically sensitive: Dr. Michael
Lax,’ an occupational medicine physician, found that his patients who had
environmental controls did much better than patients without adequate
environmental controls. A survey of 305 persons with chemical sensitivity by
DePaul University2 found that they experienced much greater relief from
environmental controls and reducing exposure than with any form of treatment,
and that the use of tranquilizing agents was actually less effective than
meditation and prayer~ The third study was conducted by Dr. Leonard Jason3 who
found that individuals who were chemically sensitive who had relatively
nontoxic housing had much better long term health than those that did not have
adequate environmental controls in their housing. This is because once chemical
sensitivity is induced, it can be exacerbated by exposures at work, at home, or
elsewhere. A fourth study of 206 chemically hypersensitive patients by Dr.
Miller and colleagues4 found that reducing exposure to chemicals was very
helpful for 71 %, but only 17% of the patients who used psychological or
psychiatric services/treatment found those to be very helpful.
1 MB
Lax, PK Henneberger, “Patients with Multiple Chemical Sensitivities in an
Occupational Health Clinic: Presentation and Followup”, Archiv. Env. Health
50:425-431, 1995.
2 Treatment
efficacy, a survey of 305 MCS patients,” The CFIDS Chronicle- Winter 1996, pp.
52-53.
3 T.H. Davis,
L.A. Jason, and M.A. Danghart, “The Effect of Housing on Individuals With
Multiple Chemical Sensitivities,” Archiv. Environ. Health. 50:425-431, 1995.
4
C.S. Miller,
“Multiple Chemical Sensitivity Syndrome”, J. Occup. Env. Med.. 37:1323, 1995.