when an alcoholic ingests alcohol, a specific allergic reaction occurs and... pffffff BWAHAHAHAHA just kidding, never believe anyone giving you this bullshit, their head is stuck so far up their ass

An allergy is a response by the immune system to a particular substance to which a person is hypersensitive;
an allergic reaction is characterized by a massive histamine release causing swelling, hives, rashes, itching, etc..

Nothing about alcoholics ingesting alcohol relates to anything regarding allergies or allergic reactions