Allergic conditions such as asthma have increased by many hundreds of percent over the past forty years in the United Kingdom, where a child born today is six times more likely to develop eczema and three times more likely to develop asthma compared to a child born in the mid-1940s.

Allergy is an over-enthusiastic reaction of the immune (defence) system of the body to any substance it considers to be dangerous. The substance could have entered the body by any route, through being eaten, breathed or absorbed from the skin, and resulting in a typical chain-reaction of biochemical alterations starting in the immune system, which can be easily monitored medically.

The person who suffers from an allergy will usually produce physical symptoms such as skin reactions, digestive disturbances, headache or breathing difficulties in response to the particular substances to which they are allergic, and all too frequently there are also mental and emotional disturbances accompanying these reactions.

However when such a reaction occurs to something consumed, contacted or inhaled, which does not involve a 'true' allergic response, it is known as an intolerance or sensitivity which can produce many of the same symptoms as a true allergy.

Intolerance commonly causes symptoms such as joint pain, arthritis-like changes, chronic fatigue and a host of emotional states involving an inability to concentrate, feeling `spaced-out` and woolly-minded, irritable, anxious or depressed?

Although the symptoms of intolerance may be indistinguishable from those which occur in allergy a problem may arise for the patient because the biochemical changes in the blood-stream, which are always present with allergy will not be found, so that the reality of their condition may be questioned by medical personnel, with the condition frequently being labelled `psychosomatic`.

Why are Allergies and Intolerances Increasing?
There seem to be a great many answers to this question, with no two people having quite the same pattern of causes. These might include deficiencies, toxicities, stress factors, various forms of infection, immune depression as well of course as inherited features.

Where food allergy and intolerance is the problem there is often a background in which early feeding patterns seem to be implicated.

At weaning, when solid foods are first introduced to a child, there often occurs a degree of indigestion (colic, loose bowel etc) or behaviourial change (crying, restlessness etc) or catarrhal symptoms (cough, wheezing, runny nose, earache etc) or a skin reaction (redness, eczema etc) or any combination of these, none of which would necessarily be considered by the parents to involve allergy at the time, who often think of these symptoms resulting from infection or `teething`.

These symptoms may be evidence of the infant being allergic/intolerant to one or other of the foods to which (s)he is being exposed for the first time. By repeated exposure, eating that same food daily or even more frequently (cows' milk, wheat, citrus etc) the acute response to the food/substance(s) would usually diminish, leaving a background, so-called `masked`, reaction which produces no obvious symptoms for a long time.

In time though, often following some additional stress factor such as an infection (or the antibiotic treatment of an infection), or vaccination, far more obvious symptoms might appear, such as asthma or eczema.