Alcohol intolerance is a genetic condition that prevents the body from being able to break down alcohol effectively. Genetic testing, either at home or at a medical facility, can confirm if a person has the condition.

However, a doctor may also be able to diagnose alcohol intolerance based on symptoms and a person’s family history.

It can be easy to confuse alcohol intolerance with alcohol allergy or other conditions that have similar symptoms. As a result, it is a good idea to speak with a doctor about any symptoms, as they will know how best to identify the cause.

This article looks at alcohol intolerance and testing.

A doctor swabbing a person's inner cheek to test for alcohol intolerance.Share on Pinterest
Dusan Petkovic/Shutterstock

If a person has alcohol intolerance, they experience immediate symptoms after consuming alcohol. These typically include:

This occurs because a genetic variation affects how the body breaks down alcohol.

Typically, the body breaks down alcohol in several ways. The most common involves two enzymes, known as alcohol dehydrogenase (ADH) and alcohol dehydrogenase 2 (ADH2).

The first enzyme turns alcohol into acetaldehyde, which is toxic. The second turns acetaldehyde into acetate, which the body breaks down into water and carbon dioxide and eliminates.

When someone has alcohol intolerance, the ADH2 enzyme does not break down the alcohol efficiently, leading to a build-up of acetaldehyde. This triggers alcohol intolerance symptoms.

Alcohol intolerance is not the same as an alcohol allergy or food intolerance, which doctors can test for by measuring the presence of immunoglobulin G (IgG) in the blood.

A person needs a genetic test to confirm alcohol intolerance. People can get this either from their doctor or from a company that provides at-home genetic testing kits.

A genetic test involves taking a blood, saliva, or tissue sample. A laboratory technician then analyzes the sample to look for changes in the genes that control ADH2 production.

Many different gene variants can affect alcohol metabolism. Some variants are more common among certain ethnicities than others. For example, a version known as ADH1B*2 is more common in people of East Asian descent.

If a person has the symptoms of alcohol intolerance and a known family history of the condition, they may not require genetic testing. A doctor may base a diagnosis on a consultation alone.

To help with this, a person should document all of their symptoms and note how long after drinking alcohol they occur. With alcohol intolerance, these symptoms begin soon after consuming alcohol.

If a person chooses to confirm their diagnosis via genetic testing, they can go through the healthcare system or order an at-home test.

There are several companies that offer alcohol intolerance tests, either as a single test or as part of a broader genetic test.

At-home alcohol intolerance test kits involve collecting skin cells from inside the cheek using a cotton swab and packaging the swab securely before sending it to a laboratory. People may receive the results in a few weeks.

Although these tests may be less expensive and more convenient than visiting a medical facility, they are not always as reliable. This is because they rely on self-collection of the sample, which can sometimes lead to cross-contamination of the swab.

In contrast, testing in a medical facility takes place in sterile conditions with a medical professional taking and storing the sample. This can help make sure the results are valid.

If a person does opt for an at-home testing kit, they should check that

  • the company is reputable
  • the tests are reliable
  • the test is for genetic alcohol intolerance and not for food intolerances or allergies

Some brands advertise alcohol intolerance tests that measure IgG reactions rather than analyzing a person’s genetics. This type of test will not show someone if they have a genetic alcohol intolerance.

Other conditions can cause symptoms that appear similar to alcohol intolerance, such as:

Histamine intolerance

Alcoholic drinks such as wine contain histamine, which occurs as a byproduct of fermentation. The body uses diamine oxidase (DAO) to break down histamine. However, people who do not have enough of this enzyme can develop histamine intolerance.

The symptoms of histamine intolerance vary, but they can be similar to the symptoms of alcohol intolerance. They include:

People may also experience these symptoms after eating or drinking other foods that contain or release histamine, such as:

  • cheese
  • cured meats
  • tomatoes
  • canned foods
  • pickled or preserved foods

For treatment, a doctor may suggest reducing histamine in the diet or taking a DAO supplement.

Sulfite sensitivity

Sulfites are preservatives that manufacturers add to some foods and alcoholic drinks, including beer and wine. Sulfites can also occur naturally in some foods.

People with a sulfite sensitivity may experience allergy-like symptoms after consuming something that contains it, such as:

Alcohol allergy

Unlike alcohol intolerance, alcohol allergies occur when the immune system mistakenly perceives alcohol as a threat. This begins an immune response that may cause:

  • hives
  • severe rashes
  • difficulty breathing
  • stomach cramps
  • anaphylaxis

True alcohol allergies are uncommon. If a person has allergic reactions to alcoholic drinks, it may be because of the alcohol itself, or the other ingredients it contains. A doctor can help with diagnosing the cause.

If a person suspects they have alcohol intolerance, they should speak with a doctor. The doctor may be able to make a diagnosis or recommend testing for allergies, intolerances, or genetics.

Some questions that a person may want to ask their doctor about alcohol intolerance include:

  • Do my symptoms match with alcohol intolerance?
  • Could it be another condition instead?
  • What tests do I need?
  • How soon will I get the results?
  • How should I manage my symptoms in the meantime?
  • Are there any treatments or home remedies you recommend?

Genetic testing can confirm if a person has alcohol intolerance. People can get kits to use at home or get tested at a medical facility if their doctor thinks it is necessary. Although at-home kits are convenient, they may not be as reliable.

If a person suspects they have alcohol intolerance, they should speak to a doctor. They may diagnose alcohol intolerance based on the person’s medical history and symptoms.

In some cases, they may recommend several tests to confirm or rule out similar conditions, such as an alcohol allergy or histamine intolerance.