Bright red skin after drinking, caused by dilated capillaries, is almost certainly an example of the alcohol flush reaction, related to the incomplete metabolism of alcohol. The condition is often genetic and is especially common in people of Chinese, Japanese and Korean descent, therefore described colloquially as the “Asian flush”.

Recent research on the genetically coded enzyme deficiency involved in the reaction has linked it to a higher risk of esophageal cancer in East Asians.

When alcohol is ingested, it is first metabolised primarily by an enzyme called alcohol dehydrogenase, or ADH. The resulting chemical, acetaldehyde, is a carcinogen. The next step in metabolism is normally for the acetaldehyde to be metabolised to acetate, chiefly by the enzyme ALDH2.

If the drinker's body makes that enzyme in a faulty variety, however, its action is weak or absent, and acetaldehyde builds up in the body. This leads to the flushing reaction, as well as to nausea and rapid heartbeat.

Those who get the gene for the faulty enzyme from both parents have reactions so severe that it limits drinking and actually protects against the greater cancer risk. Inheriting one faulty gene means a milder flushing reaction, which allows drinking and has been linked to a much higher risk of esophageal cancer among even moderate drinkers.

For most, however, it's a condition one can get used to, after regular moderate drinking, wherein repeated exposure to alcohol eventually lessens the effects, according to many sufferers.  So should you find yourself drinking with a friend who isn't so lucky, remember there's no need to tell her she is red. Her burning-hot face, pounding heart and creeping nausea have already told her everything she needs to know.

—©2014 The New York Times