Alcohol Allergies and Alcohol Intolerance

Alcohol intolerance vs. allergy

If you have a reaction to an alcoholic drink, you may have one of two things—a true allergy or an alcohol intolerance. While both are reactions to alcohol and can sometimes cause similar symptoms, they are different issues.

An alcohol allergy means you’re allergic to an ingredient in the drink. For example, you may be allergic to red grapes in red wine, preservatives like sulfites, or to gluten in some beers. Your immune system is reacting to an ingredient in the drink.

An alcohol intolerance is when your body can’t process alcohol the way that it should.

The main treatment of both conditions is avoiding alcohol or the ingredients that trigger the allergy. For allergic reactions, taking an antihistamine like Benadryl for a mild to moderate reaction can help.

Anaphylaxis is a severe and life-threatening allergic reaction that can cause dangerously low blood pressure and problems breathing. Call 911 immediately. If you have a severe reaction and carry an EpiPen (epinephrine), use it and call 911.

Acetaldehyde plays a crucial role in alcohol intolerance. When you drink alcohol, your body breaks it down into acetaldehyde, a toxic substance that is normally converted quickly into harmless acetic acid by an enzyme called aldehyde dehydrogenase (ALDH). However, people with alcohol intolerance often have a genetic variant that causes ALDH to work less effectively. As a result, acetaldehyde builds up in their body, leading to uncomfortable symptoms. This accumulation can cause facial flushing, nausea, rapid heartbeat, and headaches – the telltale signs of alcohol intolerance. Interestingly, some researchers suggest that this acetaldehyde buildup may actually serve a protective role against heavy drinking, as the unpleasant symptoms discourage excessive alcohol consumption.

Alcohol intolerance

When you have an intolerance to alcohol, your body is lacking an enzyme that is needed to process alcohol. If you do not have the enzyme or the enzyme does not work properly, then the toxic product of alcohol, called acetaldehyde, will build up. That build-up causes the symptoms.

Alcohol intolerance is also known as alcohol flushing syndrome, alcohol rash, or aldehyde dehydrogenase 2 deficiency. The condition is often inherited from your parents and common in people of East Asian descent.

A sign that you may have an intolerance is that you have symptoms no matter what type of alcohol you drink.

Symptoms of alcohol intolerance

• Skin flushing, especially to the face
• Nausea
• Rapid heart rate or abnormal heartbeats
• Runny or stuffy nose
• Vomiting
• Diarrhea
• Headache
• Worsening of asthma (only if you already have asthma)

Spotting the signs of an adverse reaction to alcohol

If you have alcohol intolerance, drinking even tiny amounts of alcohol can cause you to flush, usually within 20 to 30 minutes of drinking. “Flushing” is when your face gets red and warm. It can be mild or severe. Severe flushing can be very uncomfortable, but it is not dangerous. 

You may also have other symptoms, such as nausea, vomiting, diarrhea, dizziness, heart flutters, and a stuffy or runny nose. It can feel like you have an instant hangover.

If you have an alcohol allergy, you can develop an itchy rash, swelling, nausea, and even breathing trouble. A severe alcohol allergy can be life-threatening.

Risk factors

You may be more likely to have reactions to alcohol if you have any of these factors.

• East Asian descent (alcohol intolerance affects 30% to 40% of East Asians)
• Family history of reactions to alcohol (alcohol intolerance)
• Having allergies to grains or to other foods (alcohol allergy)
• Having asthma or a runny nose (alcohol allergy)

Treatment

If you have alcohol intolerance, you should avoid drinking. If you do choose to drink, limit how much you drink and stop drinking at the first sign of symptoms. The symptoms will pass on their own. You can treat symptoms, like headache, with certain over-the-counter (OTC) medicines.

If you are having an allergic reaction to a drink, immediately stop drinking it. You may need to take an OTC antihistamine. Antihistamines block the body’s release of chemicals like histamine that cause hives, itching, and other allergy symptoms.

Monitor yourself for any changes in your breathing. If symptoms are getting worse, you have swelling, or you have breathing trouble, go to an ER. Follow your allergy action plan if you have one, which may include using an EpiPen.

Medication

• For an allergic reaction: Take OTC antihistamines such as cetirizine (Zyrtec), fexofenadine (Allegra), or loratadine (Claritin). Be cautious if you use certain antihistamines like diphenhydramine (Benadryl), which can make you very sleepy, especially if you have had alcohol. It can also cause potentially dangerous side effects if you take too much.
• For severe allergic reactions: You may need prescription medications like epinephrine (EpiPen) or prednisone (Deltasone) if you have trouble breathing or swelling. If you need to use an Epi-Pen—or even feel like you need to use it—go to the ER immediately as you may be having a severe allergic reaction.
• For headache: Take OTC acetaminophen (Tylenol) or non-steroidal anti-inflammatories like ibuprofen (Advil, Motrin).
• For nausea: You may feel better just by letting yourself vomit. You may also try OTC remedies such as products with ginger (ginger ale) or prescription anti-nausea medicines like ondansetron (Zofran).

Preventative tips

If you don’t know if you have alcohol intolerance or alcohol allergy, see your doctor or an allergist. The only way to prevent an allergic reaction is to avoid the substance that causes it. Seeing an allergist can help you figure out what you’re allergic to.

For severe allergies, avoid the allergen completely, and always carry your EpiPen with you in case of an emergency.

The only way to prevent alcohol intolerance symptoms is to avoid alcohol completely. In addition, people with alcohol intolerance have a higher risk of certain cancers like throat cancer and Alzheimer's disease if they drink. To keep your risk as low as possible, avoid alcohol entirely.

Some people take medicines like the antihistamines diphenhydramine (Benadryl) or famotidine (Pepcid) about 30 minutes before drinking alcohol. This may be harmful because it can mask severe symptoms that could be brewing like shortness of breath.

Taking antihistamines regularly before drinking could also cause your body to build up a tolerance to the medicines. Your judgment may be impaired and you may continue to drink even when your body is trying to tell you to stop. Talk with your doctor before taking any medications to help prevent allergic symptoms from alcohol.