I'm glad this worked for you. I do not recommend your course of action to others.
I am allergic to foods and I take antihistamines if I accidently eat them and have a reaction, I dont' think a liquid diet will help. Once the food is in your bloodstream drinking a liquid diet can not stop the reaction once its started. I drink lots of water, but that is because my lips swell a bit and they burn because of it so it makes me thirsty.
My point is that if you are allergic to penicillin or sulfa drugs - don't eat foods that have these drugs in them. Forget the liquid diet if you don't think it will do any good, but avoid foods that contain these drugs if you are allergic to these drugs. That is the message I'm trying to convey. It may seem like common sense but you can't believe how few doctors warn their patients who are allergic to penicillin to avoid foods that may contain penicillin - and that would be most poultry products, other commercial meat products and possibly dairy products. Buy food that are antibiotic free - believe me it works to avoid allergens.