Urticaria problem. It be bile problem?

I have been suffering from urticaria for Las 3 months. There is this hives which spreads all over my body with itching sensation. I had got my blood and stool tested all came out normal. However as far as my bowel movement is concerned it is not really consistent. Could it be bile problem? The hives go away once I sleep and comes back after I about couple of hours after I wake up. I was taking Allegra 180 which was helping me for some time but the hives come back again after I guess the effect of medicine is gone. I have been refraining from taking this medicine for few days now. It is also not that the hives are always there throughout the day. The severity of this keeps changing throughout the day for no apparant reason. Please advise what kind of treatment I should go for. Thanks