True alcohol allergies are rare but the reactions can be severe. What most people believe to be alcohol allergy is actually a reaction to an allergen in the alcohol. Common allergens in alcohol include:
- histamines (often found in red wine)
- sulfites (often found in white wines)
People often call alcohol intolerance an alcohol allergy — and vice versa. People who have a true alcohol allergy should avoid drinking.
Research into alcohol allergies is limited. It has mostly focused on aldehyde dehydrogenase (ALDH2). ALDH2 is the enzyme that digests alcohol, turning it into acetic acid or vinegar in the liver. Someone who has a vinegar allergy may have a severe reaction after drinking alcohol. Research shows that a gene change called a polymorphism, more common in people of Asian descent, inactivates the enzyme ALDH2. It’s then impossible to turn alcohol into vinegar. This condition may be referred to as an ALDH2 deficiency.
Alcohol can also trigger allergic reactions or irritate existing allergies. A Danish study found that for every additional alcoholic drink consumed in a week, the risk of seasonal allergies went up 3 percent. Researchers believe that bacteria and yeast in the alcohol produce histamines. These caused symptoms such as itchy eyes and stuffy nose.
People who suspect they've had a reaction to alcohol should see an allergist.
Even a small amount of alcohol can cause symptoms in people with true alcohol allergies. These can include stomach cramps, difficulty breathing, and even collapse.
Reactions to various ingredients in alcoholic beverages will cause different symptoms. For example:
- someone who is allergic to sulfites may experience hives or anaphylaxis
- someone who is allergic to histamines may experience nasal swelling and congestion
- alcohol high in sulfates may increase asthmatic symptoms in those with asthma
- alcohol may increase the reaction to food allergies
Other symptoms related to the ingredients found in alcoholic beverages may include:
- nasal congestion including runny or stuffy nose
- abdominal pain
- rapid heartbeat
Rashes and Alcohol Flush Reaction
Some people may experience face reddening (flushing) when they drink alcohol. This alcohol flush reaction is more common in those of Asian descent, due to polymorphism. Facial flushing is not an allergic reaction, just a side effect of alcohol intake in some people.
According to a 2010 study published in BMC Evolutionary Biology, the gene change responsible for the polymorphism is linked with the domestication of rice in southern China several centuries ago. People with the changed gene are at lower risk for alcoholism than others, largely because of the unpleasant reaction that happens after drinking alcohol.
While reddening of the face may happen to people with an ALDH2 deficiency, some people develop red, warm, blotchy skin after drinking an alcoholic beverage. This symptom is often related to sulfur dioxide. Sulfur dioxide is commonly used to process and help preserve alcohol. This agent may trigger reactions to allergens such as wheat or sulfites. Histamines and the tannins found in wine may also cause rashes in some people.
The only way to avoid symptoms of an alcohol allergy is to avoid alcohol. Switching to a different drink may solve the problem if you’re allergic to a particular ingredient. Antihistamines (either over-the-counter or prescribed) may be helpful to treat minor symptoms in some people. People who've had a severe allergic reaction to certain foods should wear a medical alert bracelet and ask their doctor if they need to carry an emergency epinephrine (adrenaline) auto-injector like an EpiPen in case of a severe allergic reaction.