Rashes and Alcohol Flush Reaction
Some people may experience face reddening (flushing) when they drink alcohol. This alcohol flush reaction is more common in those of Asian descent, due to polymorphism. Facial flushing is not an allergic reaction, just a side effect of alcohol intake in some people.
According to a 2010 study published in BMC Evolutionary Biology, the gene change responsible for the polymorphism is linked with the domestication of rice in southern China several centuries ago. People with the changed gene are at lower risk for alcoholism than others, largely because of the unpleasant reaction that happens after drinking alcohol.
While reddening of the face may happen to people with an ALDH2 deficiency, some people develop red, warm, blotchy skin after drinking an alcoholic beverage. This symptom is often related to sulfur dioxide. Sulfur dioxide is commonly used to process and help preserve alcohol. This agent may trigger reactions to allergens such as wheat or sulfites. Histamines and the tannins found in wine may also cause rashes in some people.