Why fo i get a red rash when i drink wine?

May be Rosacea: You may have something called rosacea. This is when some blood vessels are closer to the top layer of skin than usual. It usually occurs on the nose and cheeks but it can involve the entire face. When any person drinks alcohol, it causes blood vessels in the body to dilate. Thus, if you have rosacea and you drink alcohol, you may see those blood vessels get redder & thicker-- looking like a rash.

Dr Altman agreed

Impossible to say: But may be do to one of the "congeners" found in wines, particularly red wines, including sulfites and similar chemicals which can cause a variety of reactions, including allergic ones with hives and other rashes. If you are drinking socially (2 or fewer drinks/day) and it occurs with red wine, try using white wine instead. If you are a heavier drinker, you need to cut down to safer levels.