system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible for someone to 'grow out' of an Allergy?
gpt
Sensitization to a certain allergen is something your body will never forget, there are a sort of memory cells in your immune system that will forever remember how to produce antibodies to a certain allergen. 

However, the presence of IgE antibodies is what determines whether or not you have an allergic reaction. The memory cells that determine whether or not your immune system will make massive amounts of IgE are activated by an IgE receptor, which means some IgE has to be present in the patients blood for the immune system to kick in.

After prolonged abstinence of whatever the patient is allergic to, it is possible that the IgE concetration is too small to be sufficient to start up the allergic reaction. You have de facto outgrown your allergy.

Some patients that suffer from more severe types of allergy are tested every two years in our lab to check for IgE concentration in blood.