Suggest Treatment For Severe Itchy Scalp

Over 4 months ago I suffered an itchy scalp which became unbearable. I have had several medications and the one I am using now is clobetasol propionate suggested by a dermatologist. Then I suffered a sever itching sensation under my right arm then it spread under the breast area on both breasts. The dermatologist gave me trim ovate cream for this, which after 10 days cleared the rash but i was still itching on and off. This has now spread down my torso around my hips then it eased off around my hips but is now further down my body and also on the inside of my knees and my elbows. There are only a few spots, it doesn t look like anything to complain about but for me the itching which usually starts early evening is unbearable. I feel totally depressed as no one can tell me what it is.