WHAT IS ALLERGY?

New Zealand Listener, Volume 14, Issue 360, 17 May 1946, Page 22

WHAT IS ALLERGY?

(Written for "The Listener" by DR

H. B.

TURBOTT

Director of the Division of School Hygiene, Health Dept.)

tively new in medicine. I do not think the Victorian era ever heard of allergy, and it is only since the first World War that scientific medicine has revealed how allergic troubles are caused and treated. Allergy is an over-sensitive-ness, or increased reactivity of the body to common substances which ordinarily are harmless. Some people enjoy haymaking; others get hay fever; pollen time brings on asthma in some, apples, strawberries and other fruits so enjoyed by many bring on eczema or urticaria in others. Allergy means that in the hypersensitive person common things act as irritants causing illness, whereas \ they leave the normal person unaffected, In some people the eating of certain foods, the breathing in of pollens, house dust or animal emanations, or contact with other excitants, upsets the skin, or the alimentary or respiratory tracts. Respiratory types of allergy are hay fever, asthma, and recurrent catarrh Skin types are ulticaria or hives, and eczema-itching types of skin trouble. Headaches and migraine may be nervous types of allergy. Food allergies may manifest themselves in any of these forms, respiratory, skin, or nervous, or may show up as bouts of sudden diarrhoea or vomiting. The puzzle with allergies is to, recognise them. You do not commonly think of an allergy if you are subject to vomiting attacks, or nervous headaches, or eczema. Often such illnesses are treated without any thought that there may be a nigger in the wood-pile--an allergy, a sensitization to something unknown. And that is just the problem-to discover what the irritant is that every so often produces certain. symptoms in an otherwise healthy person. As the years go by the list of things that can cause allergy is constantly growword allergy is compara-

ing, as more and more allergies are being recognised and proved. If careful observation and questioning point to any particular thing as the likely irritant, it is an easy matter to decide the issue by testing the skin of the sufferer with the suspected cause. Various extracts of pollens, animal hairs, house dust, fodds and hundreds of suspected causal agents, are available. The laboratories make these extracts of the things thought most likely to cause allergy. The doctor decides from his questioning the most likely things to try out, and on the forearm makes 10 or 12 tests about an inch apart. This is done in the form of little scratches, not deep enough to draw blood. A drop of the testing material is rubbed into the scratch. A positive reaction is evident in 10-20 minutes as an itchy, raised weal, with redness around it. Another method is to give first of all a purge. Then the patient is allowed only one food, maybe a sugar, or perhaps meat, for three days, following which one more food is added each day. When allergic symptoms occur they are probably caused by the last food added to the diet. Whether the cause is discovered by skin tests, or by diets, the treatment is simple. It may be something that can be avoided — for example, eliminating kapok from a home, if kapok is impli-: cated, or cutting out pork, shellfish, or strawberries, or some other food. But the cure may not be so easy-it may be a food that cannot be done without, or an irritant that cannot be avoided in daily life. Then the treatment is desensitiza-tion-it may seem funny, but all that is required is to have repeated injections of the extract that causes the trouble. Gradually the body learns to suffer these little doses without upsets, and slowly but surely the allergy is mastered. But it is clear that such a victory may not come easily, but from painstaking medical investigation of a co-operative sufferer.