Alcohol Intolerance: Signs, Symptoms, & Causes

What Is Alcohol Intolerance?

Someone with an alcohol intolerance lacks the proper enzymes to metabolize alcohol’s toxins. This inherited genetic trait is most seen in Asian and Polynesian populations. The ALDH2 allele gene is specifically associated with aversive alcohol reactions.² However, it’s also possible that other ingredients in alcoholic drinks like grains, sulfites, histamine, or other preservatives can also cause a reaction or sensitivity to alcohol intake.

Someone with an alcohol intolerance experiences acute discomfort after drinking any amount of alcohol. Physical symptoms tend to be mild, but the most prevalent ones are skin flushing, and experiencing a stuffy or runny nose. The intolerance will occur regardless of the type of alcohol someone drinks. Alcohol intolerance is distinct from alcohol use disorder because it happens regardless of how much someone drinks. Alcohol use disorder, on the other hand, refers to a persistent pattern of being unable to control drinking.

Alcohol Intolerance Vs Alcohol Allergy

Alcohol allergies are immune-triggered responses activated by the presence of alcohol while an alcohol intolerance is triggered by the body’s inability to metabolize alcohol absorbed in the bloodstream. Alcohol allergies are relatively rare, and they are different from having an alcohol intolerance. An intolerance generally causes mild distress and flushing. However, an alcohol allergy will trigger serious reactions, including breathing problems, stomach issues, severe rashes, and possibly anaphylaxis. The response can be similar to those with severe food allergies, and it can occur from trace amounts of alcohol.³

Signs & Symptoms Of Alcohol Intolerance

Alcohol intolerance symptoms can emerge in different ways, and the symptoms generally tend to be mild. Facial flushing is the most common symptom, and the skin will temporarily feel warm and turn red or blotchy. Some people may also notice immediate head tension and a sense of fatigue immediately after drinking.

Signs and symptoms of alcohol intolerance include:

Immediate Symptoms

Most people with an alcohol intolerance will notice immediate symptoms that arise just after drinking. Sometimes these symptoms can be confused with other medical conditions, and people might also assume they have an allergy to drinking. Generally, based on the severity of the intolerance reaction, the symptoms will dissipate after a few hours.

Immediate symptoms of alcohol intolerance may include:

• Hives: Hives is a skin rash that entails itchy, red bumps. They are generally not dangerous and disappear on their own. However, they can be physically uncomfortable.
• Rapid heartbeat: Alcohol can cause the heartbeat to increase. This also usually corrects itself quickly. However, if you have preexisting cardiovascular issues, medical complications could arise.
• Migraines: Some people with alcohol intolerance experience migraines after drinking. These tend to go away after a few hours or a day, but they can be physically distressing.
• Gastrointestinal distress: Alcohol can cause cramping, diarrhea, constipation, or other forms of stomach pain. This can be concerning if there are underlying digestive issues.
• Breathing problems: In more severe cases, people with alcohol intolerances may start wheezing after drinking. Or, they will have trouble breathing normally. If this is the case, it’s important to seek immediate medical attention.

Delayed Symptoms

Sometimes alcohol intolerance can lead to delayed symptoms that occur several hours after drinking alcohol. These symptoms may be more magnified in older people or people with more moderate or severe intolerances. They might also be heightened if someone with an intolerance drinks frequently or struggles with alcohol dependence.

Delayed symptoms of alcohol intolerance may include:

• Hangover: Alcohol intolerances may increase the risk of having a hangover. The hangovers can range in severity, but they might feel more intense than in people without such intolerances.
• Alcohol-related asthma: Research shows that alcohol may trigger asthma, even though experts aren’t exactly sure why.⁴ With that, people with alcohol intolerances might be more susceptible to asthma symptoms in asthmatic individuals.
• Diarrhea: Gastrointestinal problems may occur just after drinking, but it’s also common for people to experience them several hours or days later. In most cases, this symptom resolves itself and does need medical attention.

How Long Do Symptoms Last?

The exact duration of alcohol intolerance symptoms depends on many variables, including how much someone drank, the severity of their intolerance, and their physical health status. In most cases, the acute symptoms disappear after just a few hours. Delayed symptoms may persist for several days. If a symptom is not going away on its own, consider seeking medical guidance.

Causes Of Alcohol Intolerance

Current research suggests that alcohol intolerance is caused by a particular genetic condition in which the body can’t effectively metabolize alcohol. This particular phenomenon is most commonly seen in people of East Asian descent.² However, people of all ages, ethnicities, and demographics can experience this type of intolerance.

Causes of alcohol intolerance include:

Genetic Causes

ALDH is one of two primary enzymes associated with the alcohol metabolizing process. Within ALDH, there are several gene variants. Within all these gene variants, some people have a nonfunctional enzyme. Research shows that having one or two copies of defective genes contributes to alcohol intolerance reactions. The presence of nonfunctional enzymes has been exhibited at higher rates in Asians.⁵

Some possible genetic causes of alcohol intolerance include:

• ALDH2 deficiency: This specific deficiency is responsible for causing facial flushing in response to alcohol.⁶
• ADH enzyme variants: Research shows that ADH enzyme variants influence responsiveness to alcohol and impact the metabolic process of alcohol breaking down in the body.
• Certain ethnic groups: As mentioned, people of East Asian descent have higher rates of alcohol intolerance than other ethnic groups.⁵

Medications & Interactions

It’s crucial that people avoid drinking when they take certain medications. Mixing both can heighten physical reactions, and it can lead to serious health risks, including overdosing. It’s especially important that people with alcohol intolerances read medication labels, as some common cold medicines or laxatives can contain up to 10% alcohol.⁷

Histamine & Sulfite Sensitivity

It’s possible to confuse an alcohol intolerance with certain ingredient insensitivities. Some people unknowingly have issues breaking down histamines and sulfites. Someone sensitive to sulfites may need to avoid specific beers, ciders, and wines. Furthermore, all alcoholic drinks contain histamines, but certain types of red wine tend to have the highest amounts.

Underlying Disease & Health Conditions

Alcohol is known to aggravate inflammation throughout the body. This phenomenon can be especially problematic for people who have autoimmune conditions like multiple sclerosis, lupus, rheumatoid arthritis, irritable bowel syndrome, and Type 1 diabetes. Drinking may cause distressing flare-ups. Alcohol can also intensify the side effects associated with cancer treatment and chemotherapy.

How Long Does It Take For Alcohol Intolerance to Show?

Most people with alcohol intolerance experience physical symptoms just after drinking (about 10-30 minutes after consuming alcohol). The first symptom tends to be a red, flushed face, and then it’s common to experience a runny nose, breath shortness, and a quickening heartbeat. Delayed symptoms of alcohol intolerance may emerge a few hours later.

Can You Develop a Sudden Intolerance to Alcohol?

If someone has a genetic intolerance to alcohol, they will not suddenly develop intolerance symptoms. They were born with that intolerance, although certain physical symptoms may become heightened over time. If sudden intolerance appears to occur, it could be due to other factors, such as medication interactions or other health conditions.

It’s also important to note that aging changes how people react to alcohol. In general, most people simply become more sensitive to toxins as they age. This can happen due to weakening liver functionality and body composition changes. In addition, other health issues may exacerbate how the body responds to drinking.

Risk Factors of Alcohol Intolerance

In most cases, alcohol intolerance is not inherently problematic or dangerous. If someone avoids drinking, they will not experience any issues. However, some people choose to drink despite their intolerance. With that in mind, it’s important to be mindful that the effects of alcohol intolerance may be intensified under certain conditions.

Risk factors for alcohol intolerance include:

• Having asthma or hay fever
• Having an autoimmune condition
• Being older
• Having a past or current alcohol use disorder
• Having other allergies or sensitivities

Complications of Alcohol Intolerance

In most cases, alcohol intolerance is not serious. While the symptoms may feel uncomfortable, they are generally not dangerous. However, if someone continues to chronically drink despite alcohol intolerance, they may be more prone to mental or physical health issues. It’s well-known that alcohol use disorder has numerous short-term and long-term consequences.

Prevention of Alcohol Intolerance

There isn’t any current evidence indicating that someone can prevent alcohol intolerance. Because it’s genetic, the only known way to avoid an intolerance reaction is to avoid alcohol as much as possible. It may also be necessary to scan various beverage labels to ensure they don’t contain any trace amounts of alcohol.

Diagnosis For Alcohol Intolerance

Some people can loosely self-diagnose alcohol intolerance based on their immediate symptoms of facial flushing, feeling hot, and having a stuffy or runny nose. They may also have family members with alcohol intolerance. Genetic tests can confirm an alcohol intolerance, and people can order these exams from either their doctor or from various at-home genetic test kits.

Tests that can help diagnose alcohol intolerance include:

Skin Test

Skin tests help pinpoint if you are allergic to something within alcoholic beverages. This quick process entails pricking the skin with a specific substance like wheat. If the person is allergic to that substance, their skin will react by turning red or developing a small, raised bump within about 15-20 minutes.⁸ The provider might also directly place ethanol onto the skin to assess for reactions.

Blood Test

Blood tests examine how the body’s immune system reacts to various substances. A blood test will measure the amount of allergy-based antibodies within the bloodstream. This data is then reviewed in a laboratory to assess reactions to certain ingredients. However, it’s important to note that allergy blood tests can result in false positives.

Neither skin or blood tests diagnose alcohol intolerance itself, they diagnose an allergy to something within the alcohol, such as wheat. These tests cannot diagnose the genetic mutation that causes alcohol intolerance.

Managing Alcohol Intolerance

To date, the only treatment for severe reactions to alcohol is avoiding alcohol altogether. Antihistamines like Benadryl or Zyrtec may help alleviate milder symptoms like itchiness. If you suspect you have an alcohol intolerance coupled with an alcohol addiction, you may be concerned about experiencing distressing alcohol withdrawal symptoms. If that’s the case, it’s best to consider seeking medical support.

Alternatives to Alcoholic Beverages

Fortunately, people have numerous options of nonalcoholic beverages available to them. Many bars and restaurants now serve various mocktails as well as nonalcoholic beers, wines, and ciders, but you should be careful as some non-alcoholic beer and drinks can contain trace amounts of alcohol.  Some people also prefer sipping sparkling water, soda, coffee, and tea. If you’re looking to cut back or stop drinking, consider experimenting with a few different brands to find your favorites.

When to Seek Professional Help

Alcohol use can become a slippery slope, particularly during times of stress. If you have alcohol intolerance and feel physically unwell after drinking, yet continue to consume alcohol, that might be a sign you need additional help and support. Unfortunately, problematic drinking often worsens with time if left unchecked. If you are struggling with your relationship with alcohol, it may be time to seek professional support. Consider consulting with a therapist specializing in addiction. They can offer guidance, tools, and support as you navigate your recovery.

You can use an online therapist directory or online therapy platform to find a provider near you. If you’d like to review medication options to help manage cravings or treat other mental health symptoms, consider meeting with a psychiatrist- many providers offer both in-person and online psychiatry options for medication management.