How do you cure urticaria? Nothing is working.

Find the cause. The itchy rash is a symptom of something else going on, either irritation, allergy, or something. In order to get the urticaria to go away, you have to find the cause and deal with that. An allergist or dermatologist would be a good place to start.
Urticaria. High dose antihistamines is the first line treatment. If this doesn't work you need to see your doctor for further evaluation.