True alcohol allergies are rare but the reactions can be severe. What most people believe to be an alcohol allergy is actually a reaction to an allergen in the alcohol such as barley, hops, yeast, rye, wheat, gluten, histamines (often found in red wine), and sulphites (white wines). Often, people refer to alcohol intolerance as an alcohol allergy and vice versa. Those with a true alcohol allergy should avoid drinking.
Although research into alcohol allergies is limited, it has focused primarily on aldehyde dehydrogenase (ALDH2), the enzyme that metabolizes alcohol into acetic acid (vinegar) in the liver. First, an individual who has a vinegar allergy may have a severe reaction after drinking alcohol. Research has also looked at people with an alteration in the ALDH gene known as polymorphism, which renders the aldehyde dehydrogenase enzyme inactive, making it impossible for them to convert alcohol into acetic acid. That type of intolerance is more common in people of Asian descent.
In addition to alcohol intolerance and allergies themselves, alcohol can also trigger allergic reactions or exacerbate existing allergies, according to Dr. Sami Bahna, former president of the American College of Allergy, Asthma and Immunology (ACAAI) and current chief of Allergy and Immunology at Louisiana State University Medical School. A Danish study found that for every additional alcoholic beverage consumed each week, the risk of perennial allergic rhinitis—more commonly known as seasonal allergies—went up by three percent. Researchers believe that bacteria and yeast in the alcohol produce histamines, which caused symptoms such as itchy eyes and stuffy nose.
"In these cases, avoiding alcoholic beverages is the best way to avoid potential reactions," Bahna says.
People who suspect they've had a reaction to alcohol should consult an allergist.
In people with true alcohol allergies, even a small amount of alcohol can cause symptoms such as stomach cramps, difficulty breathing, and even collapse. A person with an aldehyde dehydrogenase deficiency will usually experience flushing and may also have symptoms such as nausea or rapid heartbeat. Reactions to various ingredients in alcoholic beverages will experience different symptoms, including the following:
- A person allergic to sulphites may experience hives or anaphylaxis.
- A person allergic to histamines may experience nasal swelling and congestion.
- Alcohol high in sulphates 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
A Note About Rashes
While flushing may occur in people with an aldehyde dehydrogenase deficiency, some people develop red, warm, blotchy skin after drinking an alcoholic beverage. This symptom is often related to sulphur dioxide, a common component in alcohol which may trigger reactions to allergens such as wheat or sulphites. 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. If a person is allergic to a particular ingredient, switching to a different beverage may solve the problem. Antihistamines (either over-the-counter or prescribed) may be helpful to resolve 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) autoinjector (EpiPen) in case of a severe allergic reaction.
Asian Alcohol Allergy
Asian alcohol allergy, also known as Asian flush syndrome or alcohol flush reaction, is caused by the aldehyde dehydrogenase deficiency as mentioned above. It is so named because it is more common in people of Asian descent than others.
According to a 2010 study published in BMC Evolutionary Biology, the gene mutation responsible for the condition coincided with the domestication of rice in southern China several centuries ago. Individuals with the mutation are at lower risk for alcoholism than others, however, due in large part to the unpleasant reaction that follows the consumption of alcohol.