l know that adults have relatively less food allergies as compared to kids. Let is say.. If l am allergic to butter when l am 2yrs old. At 20 years of age, would my allergies be gone? Or would it stay dominant in my body and l will have to refrain from butter for the rest of my life?
erm.. ic.. But if the allergy is there, it will always be there?

There is no way to tell. Some people outgrow their allergies, some people don't. New allergies can appear at any age for no reason. The safest way to find out is to see an allergist every so often & have the tests run to see what u r still allergic too.

To answer u question in the additional details: what l am saying is there is no way to know if it will always be there. It might go away, it might not. Some do, some don't. To find out if it is still there, rather than eating butter & seeing if u have a reaction, u should go to an allergist who can test u & see if u still have it.