Hi i have allergy without cause red patches suddenly and disappear it happen with eat and some times without cause?

Sounds like Hives: Sounds like you are having hives, and that may be due to an allergy, but frequently it is non-allergic. If you are having difficulty finding a consistent triggering exposure that causes an outbreak, there is good chance the hives are non-allergic. I recommend an evaluation by a board certified allergist who will take a thorough history to help determine if there is an allergic cause.