Urticaria The first, most important investigation is to take a detailed history, says Dr Harry Brown. by Dr Harry Brown Sign in to continue Sign In Email address Password Stay signed in Trouble signing in? Reset password: Click here Need help? Email us Register FREE Limited free articles a month Free email bulletins Register Now Register Now Take a 30-day trial Join MIMS now and pay nothing for the first 30 days Join GPOnline now and pay nothing for the first 30 days Sign Up Sign Up