Some people have allergy-like symptoms after ingesting alcohol, but because alcohol allergy is rare, it's possible these symptoms are more likely to be due to alcohol intolerance.
Is it an allergy or intolerance?
A true alcohol allergy will involve the immune system mistakenly producing IgE antibodies to fight off the allergen, thinking that it is a dangerous invader such as a virus or bacteria. For people with a true alcohol allergy, symptoms can be triggered by consuming only 1ml of pure alcohol - this is the equivalent of a mouthful of beer or 10ml (2tsp) of wine. Symptoms include skin rashes, stomach cramps, difficulty breathing and collapse. They can occur when drinking any type of alcohol or they might be triggered when drinking only a certain alcoholic drink such as a specific type of wine.
Alcohol can also make symptoms of other food allergies worse and lead to anaphylaxis, a potentially fatal condition. In people with asthma, alcohol can cause wheezing.
However, a true alcohol allergy is rare. Adverse reactions when ingesting alcohol, such as headaches, skin flushes and nasal and digestive problems, are more often caused by alcohol intolerance. This condition occurs when the body cannot produce a specific enzyme used in the digestion and elimination of certain substances. People of an Asian background, for example, may have a mutated gene that affects how alcohol is converted to acetic acid (vinegar) by the liver, so they may have symptoms such as skin flushes, nausea and rapid heartbeat when drinking alcohol. In people with alcohol intolerance, the food substance that triggers a reaction can be either the alcohol itself or an ingredient in the drink.
Alcohol increases the digestive system's ability to absorb food molecules into the body. This means that for people who have mild food intolerance and do not normally have a reaction, they can experience symptoms if they combine alcohol with a food trigger.
Symptoms that may indicate an alcohol sensitivity include:
What ingredients might trigger symptoms?
The alcoholic drink that is most likely to trigger symptoms is red wine. Whisky is the second most common trigger, followed by beer, then other wines. A reaction can be to a specific food substance in an alcoholic drink, such as a grain used to make whisky or the grapes used in producing a certain type of wine, such as a Shiraz. It is thought that the congeners (by-products of fermentation in some alcohol) that add body, aroma and flavour to the drink are also triggers.
Ingredients and chemicals in alcohol that can cause symptoms include:
- Fruits and flavourings, used in making the drink, including grapes, apples, juniper berries, hops, coconuts and oranges, can trigger a true allergic reaction. As well as wine and champagne (the most obvious drinks made from grapes), ouzo, vermouth and cognac are made with grapes and should be avoided by people allergic to this fruit.
- Grains, such as malt, barley or wheat, can trigger a true allergic reaction.
- Yeasts, used to ferment beer, wine, cider, sake and other drinks, are a possible trigger for a true allergic reaction.
- Mould, in the form of fungal spores that form on the corks used in wine bottles, can trigger a true allergic reaction.
- Histamine, used especially in red wines but also in many other alcoholic drinks, can trigger headaches, flushes, nasal symptoms and digestive problems and affect asthma.
- Sulphur dioxide/sulphites, often added to home-brewed beers and wines in the form of sodium metabisulphite, can trigger wheezing in people with asthma and also lead to anaphylaxis in some people.
- Additives, such as tartrazine and sodium benzoate, can trigger urticaria and asthma.