Suggest Treatment For Dermatographic Urticaria

I have dermatographic ulticaria since I was 13 years old and now I am 27 years old. If i scratch anywhere or get scratched by mistake wheals appear which disappear in 15-20 mins. My problem started a year ago when I developed intense full body itching without rashes. I would itch and wheals would appear and then it used to subside but the itching was continuous. I went to dermatologist, he gave me levocetrizine twice daily for 1 week. After taking that I got no permanent relief, it was only symptomatic. I used homeopathic medicine and it was cured. Now again since 20 days I am experiencing the same problem which has only intensified with passing days. I took levo cetrizine for 1 week and now it also does not provide symptomatic relief. Wherever I itch it gives burning sensation. But the itching is intense and full body. Im fed up. Please help. I am a working person so managing has become very hard.