I have been suffering with an itch like you descibe all my adult life, I'm now 45. I have been to every allergy expert, dermo, etc in NSW Australia. They call it urticaria but I don't get the rash that goes with it, just the unbearable itch. I was put on cortisone tablets for 6 years which stopped it but now they have caused lots of damaging side effects so stay off that if you can stay sane without them. I now take Telfast 180 (4 a day) without any side effects. These help if I get as cold as possible before and after showering & try not to stress about it. Best of luck, you have my deepest sympathy.