Removing all foods from diet. Fast for a day then one week at a time add one staple food to your diet. If no reaction then add second food and each week add one at a time to eliminate foods you are allergic to. Or you can go to the Dr's and get a simple blood test and that will tell you. Simple. That will let you know if your liver is shutting down also. Blood tests are easy to perform.
Keeping your diet simple and clean is an easy way to heal yourself.