Sudden Alcohol Intolerance: Symptoms and What to do

Table of Contents

Sudden alcohol intolerance is an inherited metabolic disorder in which the metabolism or breaking down of alcohol is altered. Due to these changes in metabolism, your face starts to become red, and you would feel warm and nauseous even with a negligible amount of alcohol. It is a condition that can be genetically transferred from one generation to the next. It could appear as soon as you start drinking or might also occur later in life.

It is also important to note that alcohol intolerance is not the same as being intoxicated or drunk.

Alcohol intolerance does not mean you have become drunk faster or drinking less alcohol. It is a different condition altogether. 

A study found that the prevalence of alcohol intolerance is about 7.2% in general. The study also found it more common in women than men. It is also seen more in people of Asian origin. A few risk factors worsen the symptoms of the condition, like being asthmatic and having a condition called Hodgkin's lymphoma.

Is it the Same as Alcohol Allergy? 

Sudden alcohol intolerance can sometimes be confused with alcohol allergy, but these two are very different conditions.

Alcohol inheritance is a genetic condition with a disorder in the metabolism or digestion of alcohol. Because of this, toxic products like acetaldehyde accumulated are the reason for the unpleasant alcohol intolerance symptoms you experience.

Alcohol allergy is a disorder related to the immune system. The immune system might overreact to one or multiple ingredients of alcohol. The ingredient might be alcohol, grain, or preservatives.

The symptoms of alcohol allergy are rashes, itchiness, swelling, and severe stomach cramps. Both these conditions can develop nausea, but the hallmark of alcohol intolerance is the flushing of the skin of the face, neck, or chest. Alcohol allergy can also be life-threatening if left untreated, and symptoms associated with alcohol allergy are usually more severe and painful than sudden alcohol intolerance.

Causes of Sudden Alcohol Intolerance

When you drink alcohol, firstly, the enzyme called alcohol dehydrogenase (ADH) breaks down alcohol into a product called acetaldehyde. Acetaldehyde is toxic to the body.

Causes of Sudden Alcohol Intolerance

In the process of breaking down acetaldehyde, there is an involvement of an enzyme called Aldehyde dehydrogenase (ALDH2). It turns acetaldehyde into acetic acid, which is a vinegar-like compound, non-toxic to the body. 

In people with alcohol intolerance, the gene involved in making this enzyme is defective, leading to decreased production of the active form of the ALDH2 enzyme. This leads to an increased accumulation of intermediate metabolic products called acetaldehyde. Acetaldehyde is responsible for the symptoms associated with sudden alcohol intolerance. When you have consumed too much alcohol, the build of acetaldehyde can produce similar symptoms even if you don't have alcohol intolerance. 

A study has suggested that rice being a common diet of people in southern China, might be responsible for a mutation that causes Aldehyde dehydrogenase (ALDH2) to be inactive.

The primary risk factor for having a problem with ALDH2 is being of East Asian descent, especially Chinese, Korean or Japanese.

Symptoms of Sudden Alcohol Intolerance

The symptoms of sudden alcohol intolerance develop as soon as you start drinking, even a tiny amount of alcohol. The symptoms can be mild to severe. Mild symptoms can be managed by avoiding alcohol consumption or limiting alcohol intake. 

The most common immediate symptom that might be noticed is warm flushing of the head, neck, and chest skin, followed by other symptoms. However, severe symptoms might require professional consultation. It's also important to note that the symptoms might vary from person to person.

Some common symptoms of sudden alcohol intolerance are:


  • Flushed skin: Skin of the head, neck, and chest might appear pink or red
  • Itchy skin or hives
  • Nausea: It can be defined as the uneasy feeling of the stomach with an urge to vomit.
  • Vomiting: It is throwing up stomach content through the mouth
  • Diarrhea: Loose and/or watery stool with increased frequency of defecation
  • Headaches
  • Fast heartbeat: Heart rate is typically less than 100. If it becomes more than 100, it's called tachycardia which is also a sign of alcohol intolerance.
  • Palpitation: Heart palpitations are a feeling like your heart is racing, pounding, or like you have missed heartbeats. It can be associated with tachycardia.
  • Low blood pressure: Blood pressure below 90/60 mm of hg is considered to be low. Some of the symptoms of low blood pressure are dizziness or fainting.
  • A stuffy nose, runny nose, or feeling of nasal blockage.
  • Fatigue: Feeling tired.
  • Worsening of asthma symptoms.


What to do if You Suspect Having Sudden Alcohol Intolerance?


Firstly, you must see your health care provider if the symptoms are severe or bothering you. Your healthcare provider might ask you about the symptoms that you are experiencing.

Following that, a test might be done if deemed necessary. The test is known as the alcohol patch test. In this test, a drop of alcohol (ethanol) is placed on a cotton pad and tapped into your arm.


The cotton gauze pad is left in your arm for around 7 minutes. After that, the pad is removed, and your skin will be examined for any redness, hives, or swelling. If these signs are present in the skin, sudden alcohol intolerance is diagnosed, and you can discuss further management plans with your healthcare provider.


Unfortunately, there is no cure for sudden alcohol intolerance. The most effective treatment is avoiding alcohol or alcohol-based food altogether. You can consider some nonalcoholic substitutions for your preferred alcoholic beverage.

Sometimes medicines like antihistamines and antacids are prescribed to mask or reduce the symptoms. But it is important to remember that these medicines do not treat the condition. You may end up drinking more, worsening the condition.

In addition, you might also need to avoid:

  • Smoking or tobacco consumption: Smoking could increase the level of acetaldehyde in the body, worsening the symptoms and increasing the risk of cancer. Furthermore, it would be best if you also avoid passive smoking.
  • Alcohol use when taking certain medications: Some medicines like metronidazole can worsen the symptoms of alcohol intolerance or can show similar symptoms when you consume alcohol while taking these medicines.


Sudden alcohol intolerance is an inherited condition. So, it is passed down from your parents to you. Therefore, you cannot do anything to prevent the disease. Still, you can prevent yourself from experiencing unpleasant symptoms of sudden alcohol intolerance by avoiding alcohol intake and following your healthcare provider's advice.

Complications of Sudden Slcohol Intolerance

This is a lifelong condition and cannot be cured. If you continue consuming alcohol, especially in large quantities, despite having this condition might lead to certain complications. The studies have suggested that even if you have mild symptoms of sudden alcohol intolerance, you must avoid alcohol consumption. It is because when you continue drinking, acetaldehyde gets accumulated over a while which could be toxic and increase the risk of developing cancer. 

Some of the complications of sudden alcohol intolerance are:

  • Pancreatitis
  • Late-onset Alzheimer's 
  • Liver disease (Cirrhosis)
  • Cancer ( most-commonly head and neck cancers)
  • High blood pressure 


Living with Sudden Alcohol Intolerance

Sudden alcohol intolerance has no treatment. Additionally, it is an inherited disorder. That also suggests you can do nothing to prevent sudden alcohol intolerance. So, the best way to live with the condition is to avoid alcohol as much as possible. There are nonalcoholic substitutions if you want to enjoy your favorite alcoholic drink. You can live a healthy, active, enjoyable life avoiding unpleasant symptoms of sudden alcohol intolerance.

If you have sudden alcohol intolerance but still drink heavily, despite the discomfort of the symptoms of sudden alcohol intolerance, you need to talk to your healthcare provider. Help is available to help you quit alcohol and lead a healthy life.


The Takeaway

Sudden alcohol intolerance is an inherited condition in which your body cannot break down alcohol with the accumulation of a toxic compound known as acetaldehyde which is responsible for unpleasant symptoms such as alcohol flushing over the skin of the face, neck, and chest. These symptoms appear rapidly after intake of a small amount of alcohol. There is no treatment for the condition. But you can avoid having these unpleasant symptoms by avoiding alcohol.

If you continue taking alcohol despite these symptoms, you may experience severe health complications.

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References used

  1. Wigand, P., Blettner, M., Saloga, J., & Decker, H. (2012). Prevalence of wine intolerance: results of a survey from Mainz, Germany. Deutsches Ärzteblatt International, 109(25), 437.
  2. Peng, Y., Shi, H., Qi, X. B., Xiao, C. J., Zhong, H., Ma, R. L. Z., & Su, B. (2010). The ADH1B Arg47His polymorphism in East Asian populations and expansion of rice domestication in history. BMC evolutionary biology, 10(1), 1-8.
  3. Vally, H., & Thompson, P. (2003). Allergic and asthmatic reactions to alcoholic drinks. Addiction Biology, 8(1), 3-11

Author: Dr. Sony S. | Panel Expert, Medical Doctor Dr. Sony is known for her medical articles, written with in-depth detail and accuracy owing to her vast medical knowledge and thorough research of each article. She completed her degree with multiple scholarships from Guangzhou Medical University and is a board-certified Clinical Doctor. She is currently working as a Medical Officer in the emergency department of a renowned hospital and continues to publish numerous medical papers and articles. Dr. Sony continues to lead the way in medical breakthroughs, unparalleled by her high level of detail, knowledge and passion for discovering new sciences and innovative healthcare treatments.

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