Sudden Alcohol Intolerance

Understanding sudden alcohol intolerance

Enjoying alcoholic drinks on occasion is by no means a health risk for most individuals and can actually offer a number of health benefits, including reduced risk of heart disease and diabetes. And while excessive drinking can lead to a hangover the next morning, there are some who experience much more serious symptoms. Even if you have been safely consuming alcohol for years, the risk of sudden alcohol intolerance is real and can lead to severe discomfort with even moderate drinking.

There is still some substantial confusion over the subject, as the symptoms associated with sudden alcohol intolerance can overlap with the effects of a hangover. To compound the problem, alcohol allergies, which can also come about spontaneously, lead to similar effects that make it hard to distinguish from true intolerance. If you are experiencing your own sudden intolerance of alcohol, understanding the difference between the three is an ideal place to start.

To begin, learn about some of the key differences between alcohol intolerance and alcohol allergies. If symptoms persist and the root cause is still not understood, talking to a medical professional is the best course of action.

Alcohol Allergy

Alcohol allergies are quite rare, although the effects can be severe. Very pronounced alcohol allergies can be triggered by as little as a single milliliter of alcohol and can lead to a series of symptoms that are similar to other types of allergies. The symptoms include itchy hives, upset stomach, nasal congestion, difficulty breathing, and unconsciousness.

However, some individuals that experience a sensitivity to some alcoholic drinks and not others may not have a true alcohol allergy, but an allergy to one of the ingredients used in making alcohol, such as grapes or rye. Unfortunately, whether you have an alcohol allergy or experience allergic reactions to the ingredients used to make alcohol, there is little that can be done to prevent symptoms, other than avoiding alcohol.

Alcohol Intolerance

True alcohol intolerance is not connected to alcohol allergies but is the result of a deficiency of a particular enzyme, called Aldehyde Dehydrogenase, or ALDH. ALDH is used by the liver each time we consume alcohol to process it so that it can safely pass through our system. Using the enzyme, our liver converts the alcohol into vinegar. Different individuals' livers excrete different amounts of ALDH, which is one of the reasons for varying levels of alcohol sensitivity across populations.

Damaged livers can stop producing enough ALDH to come with alcohol intake, leading to a sudden intolerance to alcohol. While mild cases can be reversible, excessive liver damage can lead to long-term alcohol intolerance. In either case, those experiencing alcohol intolerance will face similar symptoms as those with an alcohol allergy, as the unprocessed toxin damages the digestive and circulatory system.

Alcohol intolerance can also be genetic. Some individuals produce malformed ALDH which is ineffective at processing alcohol. In these cases, the intolerance is not reversible and symptoms cannot be avoided.

What causes sudden alcohol intolerance?

Aside from allergic reactions and genetic forms of alcohol intolerance, sudden alcohol intolerance can be caused by a number of factors:

  • Certain types of antibiotics or antifungal medications can inhibit ALDH production. If you are experiencing sudden alcohol intolerance after recently starting one of these drugs, wait until your treatment is complete to begin drinking again.
  • Sulfates and other preservatives within alcohol are known to cause reactions.
  • Histamine, a byproduct in certain fermentation products, is known to cause unpleasant reactions in some cases.

Taking the next steps

If you think your sudden alcohol intolerance is the result of liver damage, then getting in touch with your doctor is the best way to find out for sure. And if your ALDH production does not seem to be the culprit, then getting a professional allergy test is the next option. Each of these can shed more light on the root cause of a recently experienced phenomenon. Unfortunately, neither of these cases comes with many solutions in the way of treatment, meaning that the only option is to reduce alcohol intake or quit completely.

Last Reviewed:
June 14, 2017
Last Updated:
October 09, 2017