What Causes Flaky Skin Along With Severe Itching On Testicles?

I have inverse psoriasis on about 80% of my body...this condition came on out of the blue about 7 years ago and has not gotten worse but not gotten any better, so today I went to take a shower and noticed that my testicles were extremely dry and flaky and itches like crazy.. I use regular Dove soap and when I get out of the shower I use a hair dryer on low to make sure my crotch is dry, and then I apply a small amount of Gold Bond body powder... Please tell me what I have to do to get this under control, it hurts and very embarrassing. Thank you for your help in advance. Brent