Alcohol Reaction (Inconsistent)

Patient: Occasionally I will get a blotchy red semi-itchy face reaction after I drink alcohol. This does NOT happen every time and I have not been able to pin point a certain drink that causes it. The reaction, if I get it, will last about 15 min and then go away at which point I could drink 5 gallons of alcohol (I don’t) and it does NOT come back. If it happens it only happens right after my first couple sips and once its gone it does not surface again no matter what I drink. What is this!!

Symptoms: Red blotchy face, warm to the touch, itchy then disappears after a while

Doctor: