This effect is not unique to alcohol but can also occur with long-term use of drugs which have a similar mechanism of action to alcohol such as the benzodiazepines, which are sometimes prescribed as tranquillizers to people with alcohol problems.
The topic of allergies has become routine in our lives, and certainly most everyone has an idea of what an allergy is. Allergies are so common a subject in fact, it seems acceptable to discuss your allergies at a cocktail party with strangers. An allergy is an abnormal reaction by a person's immune system against a normally harmless substance.
An allergy is a reaction by your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm.