Good question, ann455. I know a little bit about this subject. Allegies can be inherited from your parents. What might be helpful is googling the question what causes allergy? That's what I ususally do when I want to know about a particular subject.
Normally, during the course of evolution from a baby to an adult, we develop a mechanism by which we desensitize ourselves to all the materials we are exposed to. But sometimes, the desensitization may not be perfect and we develop allergic reactions to those few substances. On exposure to the allergen, an Immunologic (IgE) or a non-immunologic reaction is set in process, which ultimately releases histamine, which acts at the peripheral receptors, resulting in allergic reactions and rashes.
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