Alcohol intolerance occurs when the body struggles to process alcohol effectively. It is not the same as an alcohol allergy, but both can cause uncomfortable reactions. A common symptom of alcohol intolerance is facial flushing, which happens when blood vessels dilate after consuming alcohol.
People with alcohol intolerance may also experience nasal congestion, headaches, or nausea after drinking even a small amount of alcohol.
This condition is often linked to genetic factors that affect enzymes responsible for metabolizing alcohol. It is more common in those of Asian descent due to a variation in the enzyme ALDH2, which breaks down acetaldehyde, a byproduct of alcohol.