Allergy, asthma, eczema and hayfever often go together, and these conditions are more common in some families than others. So your genes are important. But that’s not enough, the following are all important too:
- The age you are when your body first comes into contact with the allergen eg food/drug/etc
- The way in which you come into contact with the allergen (on the skin, by eating it, etc)
- How much of the allergen there is
Unborn babies in the womb are also being exposed to foods their mothers are eating via the amniotic fluid.
Being allergic to one thing makes you more likely to become allergic to other things, particularly foods of the same type eg nuts, pulses (lentils, beans etc), fruit, grains (eg wheat, barley).
If your body is regularly coming into contact with something (by touching, eating, etc) then your chance of becoming allergic is much less.