Alcohol Intolerance

It is not unusual to experience allergy-like symptoms following ingestion of alcohol. The reaction can be very specific, for example to a certain type of wine, or can be caused by different types of alcohol.

True allergy is caused when the body mistakenly makes antibodies against a substance, which causes a reaction next time the substance is taken.

True allergy to alcohol is extremely rare, although cases of skin rash reactions have been recorded. More often, the alcohol molecule exacerbates underlying conditions such as asthma, urticaria and rhinitis because it opens up blood vessels. Allergic people may get wheezy, headaches and skin flushes.

More commonly, symptoms are caused by an intolerance to alcohol, or to the food on which the drink is based (e.g. grapes for wine, grains for whisky etc), or to another substance in the drink (see below). An intolerance may arise when the body is lacking an enzyme that is needed to properly digest and eliminate a food or substance (or in this case, the alcohol itself). If the alcohol molecule cannot be effectively dealt with by the body, it can cause unusual symptoms to occur.

Alcohol also increases the permeability of the gut, which allows more food molecules into the body. This may explain the reactions of mildly food sensitive individuals who may not react to the food alone but only when it is combined with alcohol.

Red wine seems to cause the most problems, followed by whisky, then beer and then other wines. Most frequently, the likely cause of a reaction is not the alcohol itself but the chemicals - congeners - which give the drink its body, aroma and flavour. Again, the reactions are only rarely true allergic reactions.

Some of the major culprits are:

Histamine

This is present in many alcoholic drinks, particularly red wines and can cause headache, flushing, nasal symptoms, gut symptoms or asthma. Some people are particularly intolerant of histamine because of a deficiency in the breakdown and elimination of histamine from the body.

Yeasts

Yeasts are a possible cause of a true allergic reaction to alcoholic drinks. However, studies show that there are only low levels of yeast allergens present in alcoholic drinks.

Sulphites/Sulphur Dioxide

Sulphur dioxide is particularly common in home brewed-beers and wines as sodium metabisulphite. This is used in the cleansing of equipment and remains in very high levels and resulting brew. Around 1 in 10 asthmatics are sensitive to sulphites and may have a wheezy reaction to alcoholic drinks. Rashes and anaphylactic reactions are rare.

Additives

Additives e.g. tartrazine, sodium benzoate - can trigger urticaria and asthma.

Plant-Derived Allergens

The fruit (grapes, apples, juniper berries, coconuts, and oranges), flavours (hops) or grain (malt) from which the drink is made can also be the cause of a true allergic reaction. However, fruit and other plant-derived allergens are mostly destroyed by processing. One unusual potential source of trouble is fungal spores (mould) from the corks of wine bottles. Sensitivity to this fungus is rare. However, if you are sensitive and draw a cork with visible mould, you potentially expose yourself to a dose of allergen. Running the neck of the bottle under a cold tap before drawing the cork would probably be the best way of dealing with this.

At present, avoidance is the only real way of controlling symptoms arising from allergy or intolerance to alcoholic drinks. If you suspect you are reacting, make a note of the type of drink (and anything else consumed at the same time) and whether or not you took exercise. If all alcoholic drinks affect you, it is probably an exaggerated response to the alcohol itself or an exacerbating effect on your underlying condition. If not, try to narrow the field down to specific drinks or drink/food combinations, so that you can avoid the culprits.