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The Informed Parent

Can My Son Be Allergic To Air Conditioning?

by John H. Samson, M.D., F.A.A.P.
Published on May. 13, 2003
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Mrs. Smith greeted me when I entered the examining room with a sense of frustration. Discreetly I looked at my watch to make sure I was not terribly behind schedule. Good! Only five minutes delayed. What a relief! Before I positioned myself on the chair across from the examining table, she began. “My seven-year-old son has been diagnosed as having asthma. He has undergone multiple skin tests for food and pollen allergies, and all have been negative. I am really confused. I felt asthma was primarily an allergic disease. My husband tells me that skin tests are not that accurate, and he is probably allergic to many things that were not demonstrated on the tests.”

“He is only partially correct,” I answered. Before I had a chance to utter another word she resumed her statement.

“I do know that when he is around cigarette smoke he wheezes. When he encounters air conditioning he also coughs and wheezes. When the weather changes he has flare-ups of his asthma. We can see no real seasonal variation. So my husband tells me that with these observations he is allergic to tobacco and probably mold because of the air conditioning.”

As she took a breath I said, “Your husband is trying hard to explain a phenomenon the best he can from his limited understanding of asthma, but...”

She interrupted after refilling her lungs with air. “I’m still bothered by the fact that all the skin tests were negative. I wonder what your thoughts are on a patient with this history.”

Finally, looking directly at me with her mouth closed, it was apparent that she was now ready for an answer.

“Mrs. Smith, asthma is a diagnosis that usually puts fear into the hearts of most parents. They remember an Uncle Fred or an Aunt Lucy who had severe asthma and emphysema, necessitating many hospitalizations. But asthma in the pediatric age group is a much less threatening disease, assuming that the parents understand the condition and comply with the physician’s medication program. It is a condition in which the medications should be used early at the onset of the symptoms. They should be used protectively on a daily basis if the attacks are very frequent or the wheezing and coughing is constant. The key concepts in managing these patients are protective medication and preventive measures.”

“I understand that. But what about the cause?” she countered.

“The question you raise is a very interesting one because it points out a very common misconception regarding asthma. Most parents believe asthma is always triggered by allergy. This is far from the truth in any age group. But it does seem in the under two-year-olds the element of non-allergic asthma is more frequently encountered. There is obviously a type of asthma that is not allergically provoked. The non-allergic asthma goes by many names. It is referred to as psychogenic asthma, meaning asthma triggered on an emotional basis. It might be referred to as exertional asthma, that is triggered by exercise. Intrinsic asthma is called that because there seems to be no extrinsic cause provoking the problem. Probably more appropriately, it is called vasomotor asthma. This latter term more descriptively portrays what is occurring in the patient’s respiratory tract.”

“In non-allergic asthma the narrowing of the airway is caused by dilatation of the vessels in the lining of the breathing tubes. There is also an associated leakage of fluid and swelling of the membrane of the breathing passages. In addition, the muscle fibers that surround the bronchial tube may contract, which in turn further decreases the internal opening of the air passages in the lungs. This significantly narrows the airway. In the process the symptoms of wheezing and coughing are provoked. For discussion’s sake we will refer to this non-allergic type of airway disease as “vasomotor asthma”. I should point out that the terms hyperactive airway syndrome (H.A.S.) or reactive airway disease (R.A.D.) are frequently used to denote this condition. These are really descriptive terms for the diagnosis of asthma and still have two categories of classification: allergic and non-allergic.”

Let me review the causes of allergic asthma at this time. The common allergic factors are pollen, animal dander, mold spores, house dust, foods and various preservative chemicals. The non-allergic causes of asthma are changes in air temperature, barometric pressure and humidity. Odors, fumes or impurities in the air, such as cigarette smoke are also frequent triggers. Stress or fatigue, and lastly infection can also institute a vasomotor asthma attack.

“Now, let us address your son’s case specifically. The fact that all skin tests are negative does not completely exclude the possibility of a Type I allergy. Their accuracy varies, depending on the type of test used, from approximately 80 - 86 percent. Therefore, there might be a possibility that your child, as your husband inferred, is sensitive to one of these products, even though there was a negative skin test. In my own practice, if I encounter a patient who does not have a seasonal variation to the symptoms, is lacking a specific allergic agent exposure history for foods or environmentals and has all negative skin tests I approach the patient as one with the diagnosis of vasomotor asthma. Fortunately, the treatment with medication is essentially the same, although there are slight variations in how each type responds to the various modalities.

Therefore, in your child’s case, you describe cigarette smoke provoking symptoms, contact with air conditioning and weather changes as being instigators for the symptoms. There is no significant seasonal change. This history certainly strongly points to a vasomotor, or non-allergic condition.

Current research has shown that patients who react to cigarette, cigar or pipe smoke do not demonstrate reactivity to tobacco when skin tested. It is, therefore, felt that these smoke particles do not act as an allergen but as a physical irritant, setting off the reactivity of the airway. Therefore, current thinking supports the impression that people who react to tobacco smoke are not truly allergic to tobacco.

These patients whose symptoms are triggered by contact with an air-conditioned environment are not, in most cases, reacting to mold spores in the filtering system. It is the change in the air temperature that creates the hyperactive airway syndrome to start. Lastly, weather changes are associated with variance in barometric pressure. Those patients who are triggered by changes in barometric pressure may be stimulated to have their asthma attacks as storms move in and out of their locale.

It should be remembered that many patients have a combination of allergic and vasomotor asthma. When one of the elements is controlled the other aspect may provoke some symptoms. With allergic asthma, one can avoid the instigating factors, or be hyposensitized against the airborne substances that cannot be avoided. Unfortunately in vasomotor asthma many of the conditions cannot be avoided. Obviously you can avoid cigarette smoke, but it is almost impossible to avoid intermittent contact with the cooled air of air conditioners, particularly in the summer. More importantly it is impossible to avoid weather changes and other triggering natural phenomenon.

In managing a patient with vasomotor asthma one has to minimize the contact with any instigating factors as much as possible. A great deal of the time this is impossible, necessitating the use of protective medication, often on a daily basis, to control the symptoms. Fortunately the medications prescribed have relatively few side effects when properly utilized and, therefore, their prolonged use has proven to be safe. Medication can be given orally, through inhalers and through nebulizers. The choice of specific medication to be used is up to the discretion of the individual physician managing the case. Only he or she knows the particular requirements of the patient. But I should add that the medications of today offer enough varying types of therapeutic approaches that most patients can be controlled and live a normal and active life without constant episodes of wheezing and cough.

The old axiom that I was taught in medical school, “All that wheezes isn’t asthma” is certainly a truism. Equally as important is the fact that all patients with asthma are not allergic.”

Mrs. Smith looked at me with a smile and said, “Now I understand. But could you come home with me and explain it to my husband?”




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