what might be the cause regarding my urticaria ?

[kuntalsaha02]

i am 23 years old .i have urticaria for 40 days. my blood report showa slight neutrophiloc leukocytosis (75-76% differential count),no eosinophilia & other parameters are normal. My serum Ig E is also normal . I have also done ANA test within this time which is normal. The rash appears each day involves all over body surface,especially the limbs. I have taken antihistamin(first,second generation H1 blocker, also H2 blocker), mast cell cell stabilizer(monokast) which are not responding to the hives . I have started taking glucocorticoid(prednisolone, deflacort) which are doing good. I have not found any trigger for this hives, which appear everyday and go away after taking steroid. What should be your advices regarding cause, treatment and remedy