Key takeaways:
A true allergy to alcohol is very rare. Most reactions after drinking are caused by alcohol intolerance or sensitivity, which can happen when your body doesn’t break down alcohol well.
Symptoms of alcohol intolerance include skin flushing, a stuffy nose, nausea, headache, or a fast heartbeat soon after drinking alcohol.
Avoiding alcohol is the best way to prevent reactions from alcohol intolerance or an alcohol allergy.
If you’ve ever had an alcoholic drink only to find your nose running and your stomach roiling, you may have alcohol intolerance. You could also be reacting to another ingredient in your drink. A true allergy to alcohol is possible, but it’s quite rare.
Alcohol intolerance or sensitivity can cause symptoms after just a few sips. Here’s how to recognize a reaction, understand what might be causing it, and prevent it from happening again.
What is the difference between an alcohol allergy and alcohol intolerance?
A true allergy to alcohol is possible, but it’s rare. Some people who think they have an alcohol allergy may actually have an alcohol intolerance, also called alcohol sensitivity.
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The key difference is how your body reacts to alcohol. A true allergic reaction happens when your immune system goes into overdrive to attack something it sees as a threat. Allergic reactions can cause hives and facial swelling. It can also cause nausea and vomiting. When severe, an allergy can also lead to a life-threatening reaction called anaphylaxis.
But alcohol itself rarely causes an allergic reaction. If you develop allergy symptoms after drinking, you may be reacting to another ingredient in the beverage, like wheat, barley, grapes, or yeast.
Alcohol intolerance doesn’t involve your immune system. It happens because your body has trouble breaking down alcohol or one of its byproducts. You may develop uncomfortable symptoms, but alcohol doesn’t cause anaphylaxis.
Alcohol allergy | Alcohol intolerance | |
Cause | An immune system reaction to alcohol or, more commonly, another ingredient in the drink | Difficulty breaking down alcohol or its byproducts |
Symptoms | Hives, swelling, itching, nausea, vomiting, wheezing, trouble breathing, or low blood pressure | Facial flushing, headache, stuffy nose, nausea, rapid heartbeat, or low blood pressure |
Prevalence | Rare | More common |
Symptoms of alcohol allergy
A true allergy to alcohol or another ingredient in an alcoholic drink may cause:
Hives or an itchy rash
Swelling of your face, lips, tongue, or throat
Nausea or vomiting
Wheezing or trouble breathing
Dizziness, fainting, or a weak pulse
Good to know: A severe allergic reaction can lead to anaphylaxis. Call 911 if you have trouble breathing, swelling of your throat or mouth, or other severe symptoms after drinking alcohol.
Symptoms of alcohol intolerance
Symptoms of alcohol intolerance often begin soon after you drink alcohol — sometimes after only a few sips. Common symptoms include:
Skin redness or warmth
Runny or stuffy nose
Nausea or vomiting
Indigestion or stomach discomfort
Rapid heart rate or palpitations
The symptoms you experience may depend on what’s causing the reaction.
What causes reactions to alcohol?
Several things can cause an unwanted reaction after you drink alcohol.
Low aldehyde dehydrogenase
When you have an alcoholic drink, your body first turns alcohol into acetaldehyde, a toxic chemical. Then, an enzyme called aldehyde dehydrogenase (ALDH) helps break down acetaldehyde so your body can get rid of it. But some people inherit a version of ALDH that doesn’t work well to break down this toxic chemical. As a result, acetaldehyde builds up and leads to symptoms of alcohol intolerance.
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These genetic changes to ALDH are more common among people of East Asian ancestry. But they can happen to people of all backgrounds.
Sulfite and histamine sensitivity
Alcoholic drinks contain ingredients like sulfites, tyramines, and histamines. These ingredients can cause reactions even when alcohol itself isn’t the problem. For example, histamine may trigger headaches, nasal congestion, wheezing, or stomach symptoms. Sulfites can cause breathing symptoms, especially if you have asthma.
One study showed that people who have a history of allergic rhinitis (hay fever) or asthma are more likely to develop symptoms of alcohol intolerance. People with aspirin-exacerbated respiratory disease (AERD) are also more likely to have alcohol intolerance.
Medication
Some medications can cause unpleasant reactions when combined with alcohol. Depending on the medication, these can lead to symptoms like flushing, nausea, vomiting, headache, and low blood pressure. These reactions can look similar to alcohol intolerance, but they don’t all result from changes to ALDH activity.
Medications that can trigger alcohol intolerance or similar reaction include:
Metronidazole (Flagyl)
Sulfamethoxazole (Bactrim, Septra)
If you’re starting a new medication, talk with a healthcare professional about how your medications interact with alcohol.
What are alcohol intolerance treatment options?
There’s no cure or medication that fixes an underlying alcohol intolerance or sensitivity. The only reliable way to prevent symptoms of alcohol intolerance is to avoid alcohol or limit how much you drink. If you react only to certain drinks, a healthcare professional can help you figure out whether another ingredient may be responsible.
If a medication is contributing to your symptoms, ask a healthcare professional if it’s safe to drink alcohol while taking it. Don’t stop taking prescribed medication without medical guidance.
An antihistamine may be able to lessen symptoms like flushing. But this isn’t really treating the problem. It may only mask the reaction.
Can you get tested for alcohol intolerance?
Yes, there are a few ways to test for alcohol intolerance. But there isn’t one test that can diagnose every type of reaction to alcohol. A healthcare professional will usually start by asking what you drank, how much you had, what symptoms you experienced, and how quickly they showed up.
Genetic testing can identify certain types of changes in the ALDH gene. But it can’t identify every possible cause of a reaction to alcohol. A healthcare professional can order DNA testing, or you can buy a test through a private vendor.
If your symptoms seem more like a true alcohol allergy, a healthcare professional may recommend allergy testing. This can also tell you if you have an allergy to another ingredient in alcoholic beverages, like wheat, grapes, or barley.
There are no skin or blood tests for sulfite sensitivity, but an allergist may recommend a medically supervised challenge. There also isn’t a test that can reliably diagnose histamine intolerance.
Frequently asked questions
Symptoms of alcohol intolerance may begin within minutes of drinking alcohol and last for several hours. How long they last depends on how much you drank, what caused the reaction, and how quickly your body processes alcohol. Get medical help if your symptoms are severe or get worse. You should also get help if your symptoms include trouble breathing, fainting, or swelling of your throat or face.
Cancer doesn’t usually cause alcohol intolerance. Some people with Hodgkin lymphoma get pain in affected lymph nodes after drinking alcohol. But this type of reaction is rare and doesn’t prove you have cancer. If you’re concerned about new symptoms, like swollen glands, fever, or unintentional weight loss, talk with a healthcare professional.
Yes, it’s possible to develop an allergy to an ingredient in an alcoholic beverage later in life. But a true allergy to alcohol is rare. If you develop a new reaction to alcohol, it may be related to a medication you started taking or another health condition. When in doubt, ask your healthcare professional.
Symptoms of alcohol intolerance may begin within minutes of drinking alcohol and last for several hours. How long they last depends on how much you drank, what caused the reaction, and how quickly your body processes alcohol. Get medical help if your symptoms are severe or get worse. You should also get help if your symptoms include trouble breathing, fainting, or swelling of your throat or face.
Cancer doesn’t usually cause alcohol intolerance. Some people with Hodgkin lymphoma get pain in affected lymph nodes after drinking alcohol. But this type of reaction is rare and doesn’t prove you have cancer. If you’re concerned about new symptoms, like swollen glands, fever, or unintentional weight loss, talk with a healthcare professional.
Yes, it’s possible to develop an allergy to an ingredient in an alcoholic beverage later in life. But a true allergy to alcohol is rare. If you develop a new reaction to alcohol, it may be related to a medication you started taking or another health condition. When in doubt, ask your healthcare professional.
The bottom line
Some people experience flushing, headaches, or nausea shortly after drinking alcohol. These symptoms are more likely to be caused by alcohol intolerance or a reaction to another ingredient in the beverage than by a true alcohol allergy. Inherited alcohol intolerance happens when your body doesn’t break down acetaldehyde as it should. Avoiding alcohol or the beverage that triggers your symptoms is the best way to prevent an uncomfortable or even life-threatening reaction.
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References
American Academy of Allergy Asthma and Immunology. (2022). Sulfite allergy evaluation.
Australian Society of Clinical Immunology and Allergy. (2024). Alcohol allergy.
Cardet, J. C., et al. (2014). Alcohol-induced respiratory symptoms are common in patients with aspirin exacerbated respiratory disease. The Journal of Allergy and Clinical Immunology. In Practice.
Dribin, T. E., et al. (2022). Overview of allergy and anaphylaxis. Emergency Medicine Clinics of North America.
Hrubisko, M., et al. (2021). Histamine intolerance-the more we know the less we enow. A Review. Nutrients.
National Library of Medicine. (n.d.). Alcohol intolerance.
Patel, K. K., et al. (2026). Classic Hodgkin lymphoma a review. JAMA Network.
ScienceDirect. (n.d.). Alcohol intolerance.
Wall, T. L., et al. (1995). Genetic influences affecting alcohol use among Asians. Alcohol Health and Research World.
