According to the experts here’s why this happens.
Flushing can happen when alcohol is not digested completely, this happens because of a genetic mutation that causes a decrease in the expression of an enzyme called ALDH2. "Some people may have a deficiency in ALDH2 (lower levels of ALDH2), which causes an inability to break down acetaldehyde, which then builds up in the body and can cause unpleasant effects, one of which is flushing but also nausea and headache." As Dr. Maxine Warren explains.
You can experience flushing when having some specific drinks and not all of the times you drink alcohol. According to Dr. Dendy Engelman, something as simple as dehydration and a “poor water balance” could contribute to flushing. According to Dr. Dendy Engelman, something as simple as dehydration and a “poor water balance” could contribute to flushing.
Some wines also have more sulfites than others, and this can also create flushing. However, sulfites are naturally present in many things that we consume, including food, so their effects may be overestimated." Flushing could also occur for other types of intolerances, like those who have gluten intolerance and experience flushing while drinking beer.
Another possibility is rosacea, this chronic inflammatory skin disorder can cause facial redness from enlarged blood vessels on the face, especially in the cheeks. Red wine has long been known to trigger flare-ups of rosacea because it causes an enlargement (dilation) of the blood vessels, “However, a study published in the American Journal of Dermatology in April of 2017 showed that white wine could also trigger a flare-up of this condition.”
If you experience flushing after drinking alcohol more often than not it’s high time you go and see your doctor. Something as simple as keeping track of which drinks trigger reactions will be very helpful for your doctor to find the exact reason for it.