Urticaria common causes are food allergy infection or drugs. It presents with itching resulting in formation of red rashes which we  call hives or wheals. Although in most cases cause remains unknown in spite of a thorough search. It can be symptomatically treated so that you do not get any new hives and the treatment should be prolonged until it resolves which usually takes 1 to 6 months. Please consult me in private for further details or visit a nearby Dermatologist