Alcohol intolerance is a relatively rare condition that causes a person to experience abnormal side effects after drinking alcohol. A person can be born with alcohol intolerance, but it can also be caused by certain medications or medical conditions. Alcohol intolerance will normally cause people to avoid alcohol, as the unpleasant symptoms are quite undesirable. What Is Alcohol Intolerance? Alcohol intolerance, also known as alcohol sensitivity, is typically caused by a change that affects an enzyme called alcohol dehydrogenase. This enzyme is part of the body’s process for breaking down alcohol, and it converts a chemical called acetaldehyde to another chemical called acetate. The change caused by alcohol intolerance makes it impossible for the body to break down acetaldehyde as it should, causing this chemical to build up in the body. The symptoms of alcohol intolerance are all related to this buildup of acetaldehyde. Alcohol Allergy vs. Intolerance Alcohol intolerance is not the same as an alcohol allergy. While both of these conditions cause unpleasant symptoms after using alcohol, the cause of these symptoms is very different. Alcohol intolerance is due to the buildup of acetaldehyde, which is caused by a problem affecting alcohol dehydrogenase. Alcohol allergy occurs when someone’s immune system reacts to the presence of alcohol, causing the body to attack the alcohol. Most alcohol allergies are actually a reaction to a component of the alcohol, such as grapes, hops or wheat, instead of the alcohol itself. Alcohol intolerance symptoms are unpleasant but rarely actually dangerous. However, alcohol allergy symptoms can range from mildly unpleasant to life-threatening. Mild symptoms include rash, but more dangerous symptoms include swelling in the face and throat, which can affect the ability to breathe. If you suspect that you or someone you know is having a serious allergic reaction, immediately call 911. Symptoms of Alcohol Intolerance The main symptom that alcohol intolerance is known for is sudden flushing in the face. Often, alcohol intolerance also causes a stuffy nose and symptoms similar to a hangover. Common symptoms of alcohol intolerance include: Redness in the face Stuffy or runny nose Hot flashes Abdominal pain Nausea or vomiting Diarrhea Headaches Alcohol Intolerance Test Alcohol allergy can be diagnosed using allergy testing specifically for alcohol and the sources that alcohol often comes from. Alcohol intolerance, however, is more difficult to test for. Physicians often diagnose alcohol intolerance based exclusively on the symptoms experienced and the fact that the symptoms develop immediately after drinking alcohol. Doctors also tend to rule out alcohol allergy before diagnosing alcohol intolerance. Genetic tests can also be done to evaluate if there are problems with the genes that make alcohol dehydrogenase. However, this is not always the cause of alcohol intolerance. What Causes Alcohol Intolerance? Alcohol intolerance can be caused by anything that affects the function of alcohol dehydrogenase. Incorrect function in alcohol dehydrogenase enzymes can be caused by genetic changes, chemical changes or heredity. Genetic Alcohol Intolerance Genetic alcohol intolerance is inherited from one’s parents, and it is caused by a mutation in the gene that the body uses to create alcohol dehydrogenase. This condition is most common in those of Asian descent but can affect anyone, regardless of their ethnic background. This genetic condition will create alcohol intolerance throughout an individual’s entire life. Alcohol Intolerance as a Result of Disease Certain diseases can affect how well alcohol dehydrogenase functions. Hodgkin’s lymphoma, ovarian cancer, breast cancer and other diseases can all cause a sudden onset of alcohol intolerance in those who never before experienced difficulty drinking. The sudden development of alcohol intolerance does not necessarily mean that a new disease is present. However, a person in this situation should still seek medical attention to ensure that a health problem has not recently developed. Alcohol Intolerance as a Result of Medications Certain medications can create alcohol intolerance by inhibiting the action of alcohol dehydrogenase. The most common medication that creates this side effect is metronidazole (Flagyl), a commonly used antibiotic. Another medication that causes alcohol intolerance is disulfiram (Antabuse). The sole purpose of this medication is actually to create alcohol intolerance, and it is used to deter alcohol use in people struggling with alcohol addiction. Alcohol Intolerance Treatment Treating alcohol intolerance depends entirely on its cause. If alcohol intolerance is due to a disease or the use of a medication, successfully treating that disease or stopping the medication will typically help resolve alcohol intolerance. If alcohol intolerance is due to genetic causes, then there is no treatment that will make it go away. Stopping alcohol use will be the only way to avoid alcohol intolerance symptoms. Though alcohol intolerance is untreatable, there may be ways to reduce the symptoms that will inevitably occur when using alcohol. This will typically involve using medications to treat the symptoms that are particular to each individual. However, drinking is usually highly discouraged in those with alcohol intolerance, as the buildup of acetaldehyde can lead to an increased risk of cancer and other serious health problems. If you or someone you love is struggling with alcohol abuse despite an alcohol intolerance, The Recovery Village at Baptist Health can help. Contact us today to learn more about alcohol addiction treatment programs that can work well for your situation. Sources Igumnova, Anastasia. “Alcohol Flush Reaction: Do You Have Alcohol Intolerance?” Atlas Blog, December 1, 2021. Accessed February 18, 2022. U.S. National Library of Medicine. “Alcohol.” MedlinePlus, February 3, 2022. Accessed February 18, 2022. Genetic and Rare Diseases Information Center. “Acute alcohol sensitivity.” July 6, 2015. Accessed February 18, 2022. EPA. “Acetaldehyde.” January 2000. Accessed February 18, 2022. Luo, Elaine K. “Alcohol Allergies.” Healthline, November 12, 2018. Accessed February 18, 2022. Australasian Society of Clinical Immunology and Allergy. “Alcohol Allergy.” March 2019. Accessed February 18, 2022. Meth, Marc. “What to know about alcohol allergies.” MedicalNewsToday, January 27, 2021. 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