ALLERGY: WHY INJECTIONS DON’T ALWAYS WORK
A thorough examination of your medical history is the first step in any approach to allergy. Sooner or later, though, the subject comes around to tests and treatment.
There’s scarcely an asthma or hay fever sufferer alive who hasn’t been pinched, punctured and impaled by skin tests or allergy injections – or both. Most traditional allergists use skin tests to identify the responsible allergens. Minute quantities of purified extracts of suspected allergens – dust, pollens, moulds and so on – are applied to or injected into the skin on the lower arm (or, less frequently, the back). If a red welt or bump (what doctors call a ‘weal’) flares up at the site of the test, it’s assumed that the person is allergic to the extract. No welt, no allergy.
And so it goes for twenty or thirty items. Traditional allergists usually concentrate on inhalants – particles of dust, pollen, mould and animal dander (fur or feather residue) – all items that provoke an IgE response. Many allergists say they cannot use conventional skin tests alone for food allergies; they just aren’t reliable enough. Instead, many prefer to use skin tests along with elimination diets. Foods are avoided and then reintroduced one by one to determine which ones can be tolerated and which cannot. Or elimination diets alone may be used. Either way, the most common food allergens – milk, wheat, corn, eggs and a few others – are the key suspects.
Avoiding what bothers you has always been the stock advice for people with allergies. That makes sense. If you start to sneeze and itch when a dog or cat enters the room, you don’t take in stray animals. If you go through truckloads of tissues when the pollen season gets underway, you don’t take long drives in the country. If strawberries make you break out in hives, you eat raspberries instead.
Many times, though, people become so sensitive that the smallest amounts of pollen, dust or whatever make them ill. Or they’re allergic to things that are impossible to avoid. Traditionally, allergists have attempted to build up an allergic person’s tolerance of such items with standard doses of the allergen. The idea is to stimulate immunity without causing an out-and-out reaction. Basically, immunotherapy (sometimes called hyposensitization or desensitization) seems to work on the same principle as vaccination against smallpox, cholera, diphtheria, tetanus and so on.
Standard immunotherapy against allergy takes about six months to build up to a protective dose, beginning with a very weak, standard dose that is gradually increased every week until protection is achieved. Injections are then given either on a regular basis or whenever a reaction is anticipated, such as at the start of the pollen season.
Yet many people go through standard allergy diagnosis and immunotherapy and still suffer. Why?
Traditional allergists are often the first to admit that skin tests aren’t always what they’re cracked up to be.
‘Some authorities claim that a good history and careful skin testing are reliable 95 per cent of the time in allergy diagnosis,’ write Dr William T. Kniker and colleagues from the Division of Immunology-Allergy, Department of Pediatrics, University of Texas Health Science Center in San Antonio. ‘In many instances it is clear that results are not that good because too many patients are incorrectly diagnosed as sensitized to various allergens and inappropriately given immunotherapy. . . . Because skin testing . . . uses unstandardized antigens, testing techniques and scoring systems, it is to be expected that misinformation commonly is obtained.’ (Italics ours.) The doctors add, ‘Skin testing in the diagnosis of allergic disease is, in reality, not a uniform technique comparably practiced by all.’ (Bulletin of the New York Academy of Medicine, September 1981.)
Obviously, any treatment based on a shaky diagnosis will be doomed from the start.
‘Undoubtedly, thousands of persons are receiving “allergy shots” on the basis of skin tests that were incorrectly performed or erroneously interpreted, or both,’ stated Postgraduate Medicine.
Incidentally, immunotherapy is only available for a few select allergies and doesn’t always bestow complete protection. So, many allergy patients are routinely prescribed drugs like antihistamines and steroids to relieve their symptoms. However, drugs do not cure allergy either and they all have unpleasant side effects.
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