Allergic tendencies are generally inherited. Studies have demonstrated that strongly positive allergy test results are the single most important predictor for the persistence of asthma in childhood. Scientists have been investigating the genes responsible for allergies. Currently, many promising genes have been reported and the allergic diseases result most likely from the interaction of these multiple genes and environmental factors. The following information may serve as a useful guide.
- 20% of the population have allergic tendencies
- If one parent has an allergy, 30-50% of the children are affected.
- If two parents have allergies, two-thirds of the children are affected.
It has been the focus of investigation why the incidence of asthma has been on the rise in the industrialized countries. Is it due to environmental pollution? The answer seems to be “no”, since the developing countries have the worse pollution, but the lower incidence rate.
Epidemiological evidence suggests that viral infections during early childhood play a suppressive role in the development of allergies. In other words, children growing up in the developed countries are more vulnerable to the allergic diseases because they are protected against infections by improved vaccines and hygiene