I have hives but im not allergic to anything. how did i get it?

Hive triggers: Hives can be a manifestation of allergies, viral infections (especially in children), bacterial infections such as strep, physical triggers like cold and heat. If hives persist beyond 6 weeks, then autoimmune trigger is possible and there continues be a large group of patients with "idiopathic" hives (cause unknown).

Many causes: In fact although acute hives are at times caused by drugs or food allergy, chronic hives often do not have an allergic cause but a presumably autoimmune cause. For most cases, we cannot find a cause despite exhaustive studies. Aside from that, there are also many so-called physical urticaria - discussion >400 words allowed in this forum.