allergic urticaria
"I was prescribed hydroxyzine 25 mg (one or two tablets at bedtime) for a very itchy rash. I have also had insomnia for years, it is not unusual for it to take 3 or  4 hours for me to fall asleep. The first time I took this medicine I was sound asleep within an hour after taking it, and I slept through the night.  I have been taking it for about 2 months and wish I had known about it sooner."