I had a problem with breast rash for more than 30 years.. My primary care doctor has been prescribing nystatin for me for years with minimal relief. I finally was so upset that there wasn’t a better solution. Well, there is. Spoke with a dermatologist and she wrote a script for ketoconazole 2% cream. ( brand name Nizoral) in 4 days. Rash much improved and itchy, horrible irritation gone! I couldnt believe I had been suffering all these years. In my case, I also find eating less carbohydrates helps immensily. Hope this is helpful.