If you experience an unpleasant physical reaction (usually flushed skin and/or nasal congestion) when drinking alcohol, it may be “alcohol intolerance.” This isn’t a true allergic reaction but an inherited inability to break down or metabolize alcohol.
An actual allergy to alcohol is rare. Symptoms may be as mild as a rash or as severe as life-threatening anaphylactic reaction. In most cases, if there is a bona fide allergy, it isn’t to the actual alcohol but to ingredients in the alcohol such as barley, hops, corn, yeast, rye, wheat, and gluten. Allergies to these other sources can cause hives, hay fever, and stomach cramping.
Alcohol can also exacerbate existing allergies. That’s because alcohol can contain histamine—a chemical which is responsible for inciting allergic reactions. Thus, if you already have seasonal or food allergies, you may find them worsen with too many drinks.
Talk to your doctor if you suspect an alcohol intolerance or allergy. He or she can help you know whether you need to lay off the drinks altogether or if allergy treatment for food allergies (in the form of sublingual immunotherapy) can help lessen your symptoms.