MECHANISMS OF ALLERGY

General Adaptation Syndrome

No reference to allergy and environmental medicine could be complete without some reference to Hans Selye’s hypothesis of stress adaptation. It is something that environmental medicine doctors have taken very much to heart, because it seems to fit our daily observations and explains a great many of the phenomena we encounter. The fact that so much to heart, because it seems to fit our daily observations and explains a great many of the phenomena we encounter. The fact that so much experience matches the theory suggests that it is ‘true’.

Hans Selye, a Viennese by birth who moved to Canada and practiced medicine in his adopted country, began with the observation that many people ill from different causes had similar symptoms. These were general symptoms, which seemed common to all afflictions, such as pallor, fatigue, loss of appetite, vague pains and a coated tongue. Selye, still a medical student, likened this to the ‘syndrome of being ill’ and he couldn’t’ understand why his teachers didn’t pay more attention to these symptoms: they were obviously important, since everybody got them, no matter the illness.

Selye eventually pursued his interest to the point of describing a mechanism of stress and adaptation that seems to be universal. It is not just applicable to humans but to all life: any organism, any stress – from an amoeba crawling into tainted water to a busy executive having a tough time at board meetings. The stages of ‘adaptation’ to outside stress he called the General Adaptation Syndrome, or GAS for short.

Briefly, stage one is the first encounter, when the body reacts and alarm signals herald the onset of some adversity (a stressor). These signals we know as symptoms: These signals we know as symptoms: pain, discomfort, etc,; some unpleasant response that entails a desire to limit the exposure by escaping from whatever is causing the symptoms.

Avoidance brings the reaction to an end and the symptoms go away. But if the individual does not desist and instead keeps on, eventually he or she might learn to tolerate the stressor and find it doesn’t worry him or her too much. For example, someone moving to a much hotter climate might feel very unwell at first, but with persistence learns to tolerate heat at a level that would have been dangerous to him or her on first arrival. We call this adaptation process stage two.

It might be possible to go on coping with a stressor to which we are adapted for a long time, perhaps indefinitely. But circumstances may come about where there is too much load at one time, or something might cause resistance to run down (a virus infection, too many late nights, intemperate drinking or even the gradual process of ageing). The adaptation is then lost and the stressor begins to produce symptoms once again. This is stage three.

But this time, the consequences are more serious. The individual concerned no longer has any powers of resistance. His or her body has run out of fight and the stress can become overwhelming. This is the stuff of coronary heart disease, perforated ulcers, cancer and strokes. When the effect is less threatening to life, increased allergies can certainly be a possible outcome. If stage two is ‘adaptation’, this stage could be termed maladaptation.

We can illustrate this with an example from an allergy doctors’ experience: If an individual, as a child, is allergic to milk, he or she will experience unpleasant symptoms when ingesting it, such as mood changes, rashes, hyperactivity or whatever (stage one).

If the parents insist that the child must continue to drink milk ‘because it is good for you’, not knowing that is the cause of the condition affecting the youngster, the child may get used it and learn to tolerate it. The rash or other symptoms may even clear up. Doctors often say that a patient can ‘outgrow’ an allergy this way. He or she is now adapted to the milk allergen (stage two).

As the years go by, little of note may be observed; perhaps just the occasional bout of illness or digestive disorder, probably made worse at examination times and other periods of stress. But gradually the clock is running down. That individual’s intolerance of milk is slowly wearing out the body’s resistance. Trouble will inevitably follow.

Either because of ageing or at a specific trigger, the milk allergy will return and symptoms start up all over again. This time it could be asthma, migraine, arthritis or any one of dozens of conditions. The patient may be quite unwell and yet never suspect milk – because he or she has always drunk it and has never had any previous trouble.

In fact patients often become addicted to their allergy food and may find that avoiding it for any period results in unpleasant withdrawal symptoms. This encourages further ingestion of the food; the patient may even feel it ‘does me good’ since it tends to relieve the symptoms. At this stage eating the food ‘masks’ unwanted symptoms; it keeps them at bay. Providing he or she eats the food regularly, ill effects are kept at a minimum. This is what we mean by a masked allergy.

You probably know that milk is often said to soothe stomach ulcers; patients who suffer this complaint are encouraged by their surgeon to drink it in great quantities. It does sometimes appear to work – you now know why!

One other example might serve, and that is smoking. Those who smoke will doubtless remember that their first attempt was accompanied by unpleasant consequences: headache, dizziness and nauseas are not uncommon (stage one). But by persisting, the would-be smoker gets used to tobacco and the symptoms are no longer experienced (stage two). Finally, as the addiction takes hold, the individual will find that unpleasant symptoms come on with a vengeance when going too long without a ‘fix’ for the nicotine craving. This is stage three and one of the hardest of all addictions to break.

Signs of Danger

TSelye published a list of warning signs that patients should look for when they are under stress and about to become maladapted to foods and other stressors. It is remarkably similar to the lists that allergy doctors have arrived at, traveling via a different route.

I reproduce them here without any comment:

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