Applying something like steroids to the skin surface has the effect of pushing the problem back into the system whereas urticaria is indicating that something needs to clear through the skin and needs to be encouraged to do so.
The condition you have is likely to be related to an allergic reaction to something in your diet or environment. I would suggest trying kinesiology which can test for allergies, but also discover what may be required to rebalance your system. Another option would be homeopathy - there is a remedy called Urtica Urens which is used to treat urticaria - a homeopath would be able to suggest other remedies to help to clear this from your system.
Hope this is helpful. Helen Fogg