Can you be allergic to alcohol? if so, what are the symptoms and how soon are they noticed?

Alcohol allergy: Alcohol can cause reactions. A hangover is really a toxic reaction. Some people have an enzyme deficiency which makes them prone to flushing of the skin especially face after drinking. Many people have nasal congestion after drinking beer or wine. Reactions to additives like sulfites can cause wheezing. True allergy to alcohol is very very rare but can cause anaphylaxis which can be severe.