What Causes Recurring Itchy Rash On Face, Head, Chest And Back?

I have a rash that occurs every month. I had shingles in Nov. 2013 and every since that time I get a rash on my face, head, chest, back, muncus (nose) mouth, crotch. They itch, burn, some drain. One diagnosis was pemphigus, other allergic to meds. Off all meds for a year and I still get the rash. With it I get sore joints and am fatigued. Thanks