Suggest Cure For Painful Itchy Rash In Underarms And Groin Area

I have a painfully itchy burning rash that developed suddenly in my underarms and groin area about 3 - 4 months ago. The skin is very red but no lesions or bumps etc. I've tried various things to treat and hopefully cure it. Stopped using deodorant recently, applied white vinegar to the areas before showering, gold bond powder etc. At times the rash seems to diminish some but never really goes away and flairs up constantly for months now.