A red, raised, itchy rash that comes suddenly, lasts for some time and then disappears without any trace is the typical history any patient of Urticaria will provide. The rashes may come and go with no apparent trigger at times. They can occur anywhere on the body and have the following features:
Some of the variants of Urticaria that differ in presentation are discussed here:
Symptoms to watch out for (report to your physician immediately if you experience any of these)