But don't use cold water in the near future anyway. Do not drink cold water! Urticaria is an immune system disease. I think it's best to use warm water if you have to take a shower and wash your hair. Never use hot water (the very hot kind). Hot water will further stimulate the rash.
I used to be a patient with severe systemic chronic urticaria, and I was sent to the hospital for emergency treatment due to tracheal edema and suffocation. After playing for several years, I seem to have really recovered. So although I am not a doctor, these experiences are still worth listening to.
So you should avoid eating seafood, beef and mutton and spicy food recently. Get better early, so as not to itch. Also, if you are sure it is acute, it is a good choice to use western medicine, which is good and fast. However, if you are unfortunately chronic, or you and your doctor are not sure whether you are acute or chronic, I advise you not to use hormones even if you have to use western medicine. I just started using western medicine. It's good and fast, and it's getting worse. It was discovered that it was chronic, and chronic urticaria must be seen by Chinese medicine.