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Alcohol Allergies and Alcohol Intolerance

Knowing the difference can help you manage what you drink.
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Written by Elliot Stein, MD.
Internal Medicine Resident, Vanderbilt University Medical Center
Medically reviewed by
Assistant Clinical Professor of Emergency Medicine, Columbia University
Last updated August 15, 2024

Alcohol allergies quiz

Take a quiz to find out if you have alcohol allergies.

Alcohol allergies quiz

Take a quiz to find out if you have alcohol allergies.

Take alcohol allergies quiz

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.

Pro Tip

Alcohol intolerance and alcohol intoxication are not the same. Alcohol intolerance is a life-long condition that you can’t control. You may feel like you have an instant hangover due to buildup of the same chemicals that a person without alcohol intolerance experiences when he or she drinks way more than the body’s metabolism can handle. —Dr. Petrina Craine

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

Alcohol allergies quiz

Take a quiz to find out if you have alcohol allergies.

Take alcohol allergies quiz

Alcohol allergy

When you have an allergic reaction to alcohol, your immune system is overreacting to an ingredient in the drink. It is extremely rare to be allergic to alcohol itself. If you have other allergies, you are more likely to have an allergy to alcohol, according to research from Switzerland.

If you ever have trouble breathing or an itchy rash with alcohol, you likely have an allergy. If you sometimes get symptoms with certain drinks but not with others, then you are more likely to have an allergy.

Symptoms of alcohol allergy

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.

Dr. Rx

If you’ve never before experienced alcohol intolerance and suddenly start having symptoms like facial flushing and nausea after drinking alcohol, check your medications. Particularly if you recently started a new one. There are some medications, like for treating bladder and vaginal infections, that can produce the same uncomfortable symptoms after drinking alcohol. Avoid alcohol while taking these medicines. —Dr. Craine

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).

Alcohol allergies quiz

Take a quiz to find out if you have alcohol allergies.

Take alcohol allergies quiz

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.

Pro Tip

Although it can be disappointing to have an intolerance or allergy to alcoholic drinks, don’t be discouraged! There are many interesting and tasty non-alcoholic beverages. Get creative and try “mocktails” and even sparkling drinks. But always be mindful of the ingredients, as people with an alcohol allergy to an ingredient like sulfite, may unintentionally consume beverages that may still contain potential allergens. —Dr. Craine

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.

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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Assistant Clinical Professor of Emergency Medicine, Columbia University
Dr. Petrina Craine is an emergency medicine physician who hails from Memphis, TN. After graduating as valedictorian of her high school, she moved to Durham, NC to pursue a degree in Biology and a certificate in Global Health. After college, she returned to her birthplace to attend the University of Tennessee Health Science Center College of Medicine. She successfully completed her medical degree a...
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References

  1. Edenberg HJ, McClintick JN. Alcohol Dehydrogenases, Aldehyde Dehydrogenases, and Alcohol Use Disorders: A Critical Review. Alcohol Clin Exp Res. 2018;42(12):2281-2297. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872347/
  2. Cleveland Clinic. Alcohol Intolerance. https://my.clevelandclinic.org/health/diseases/17659-alcohol-intolerance