This is a natural question that may arise while studying the basics of allergy. It’s a fact that some people may be affected by a certain allergen, while the others are not. This means that everyone does not have allergies.

People who are allergic produce more IgE (Immunoglobulin E) compared to the quantity produced by a non-allergic individual. The primary cause behind the excess production of IgE is genetic. In most cases, the allergy history of parents decides whether the child is going to be allergic to a certain substance or not. If your parents are not allergic to anything, your chance of getting allergy attacks is about 15%. On the other hand, if any one of your parents has suffered from allergies at some point of time, then the risk of you getting such attacks mounts up to 30%. When both parents are allergic, the probability of occurrence of allergies in their children becomes 60%. However, it’s still unclear why a particular substance acts as an allergen and others does not do so for the same person.

Environment also plays a major role in triggering allergic symptoms. A person who gets exposed to a particular allergen intensely and repeatedly much earlier in life has high chances of getting allergy attacks.