I get rashes during all my fasts. It is a sign of detox, but also it means your liver is not functioning properly. Use coconut oil on your skin, it will minimize itching.
After you complete your fast, eat raw fruits and vegetables for 1X, if not 1.5X the number of days you fasted, then do liver flush. It will take a few Liver Flushes for you to clean your liver. Also include all liver function enhancing herbs and foods in you diet.