Greetings .Hives (chronic urticaria) is a condition where an itchy rash persists on and off for six weeks or more. 'Chronic' means persisting for a long time or constantly coming back.In many cases the cause may be an autoimmune problem.Stress, infections,some food items or medicines may be a trigger in some cases and without seeing can't say much.I hope this information helps you in some way. Regards Dr Shuhaib MP(Pune)