The medical controversy about adverse reactions to food is compounded by a long-running dispute over the meaning of allergy. For a word that is scarcely more than 80 years old, it has had a very chequered career. A Viennese doctor, Baron Clemens von Pirquet, first used it in 1906 to mean ‘altered reactivity’. CanadianPharmacyMeds.com Von Pirquet was a paediatrician and he felt the need for a new medical term to describe certain reactions in his young patients. These changed reactions included the development of immunity to infection, on the one hand, and marked reactions to certain foods, pollen or insect stings, on the other. He was principally concerned with reactions involving the immune system, the set of cells that protect our bodies from infection. But he apparently intended his newly coined word to mean any altered response to the environment. In this context, environment means all the external things that can affect the body, whether in food or water, in the air we breathe, or in things that come into contact with our skin. Von Pirquet also introduced the word allergen to describe the substances that brought about these changed reactions.
At that stage, very little was known about how some of these reactions might arise. The following decades brought greater understanding, and the meaning of allergies was narrowed down – the development of immunity to disease was dropped from the definition, because it was obviously something quite different from adverse reactions to food, pollen or bee stings.
In 1925, the definition of allergy was narrowed down still further. CanadianPharmacyMeds.com Experiments had shown that many adverse reactions to pollen or food could be transferred from one person to another by injecting a small amount of blood serum into the skin. The area around the injection site became very sensitive to the allergen. This, and other evidence, indicated that the immune system really was at work in these cases, as von Pirquet seems to have suspected. Most of those working in the field decided to limit the definition.
Until fairly recently, most conventional allergists believed that the sort of symptoms seen in a patient depended largely on the type of allergen involved: the part of the body affected would be the part that first encountered the allergen. Thus, allergens that fell on the skin or brushed against it, called contactants, would tend to produce skin reactions such as eczema. Inhaled allergens or inhalants, such as pollen or dust, would produce symptoms in the nose and airways. Food allergens, obviously, would produce symptoms in the lips, mouth, stomach and gut. It was all very logical.
Among the patients treated by allergists, there were always some whose allergens could not be identified. With these unfortunate patients, it was assumed that some other non-allergic mechanism was producing the symptoms. Asthma patients, for example, were given the label ‘intrinsic asthma’ if no allergen could be pinpointed. Like many of the labels used in medicine this is just a clever way of saying that no-one has any idea what is causing the disease. These insoluble cases were an indication that something was wrong with the traditional concept of allergies, although few doctors realized this at the time.