I have been taking 40mg prednisone every other day for myastheni...

I have been taking 40mg prednisone every other day for myasthenia gravis, Isaw My doctor yesterday due to a bright re rash that is barely raide..not real itchy is spreading from start point of inside my arms..like opposite elbows. It is also under my breasts, in my belly button. He seemed stumped and thought it might be a side effect of prednisone catching up with me . I have a steroid cream he has me applyin 2 x day and now it is on my neck this am and I AM SEEING TINY BLISTERS AND different shapes. I wonder if I could have a systemic fungus or infection the prednisone hides and how do you tell if you have a prednisone rash or fungal infectio, ' Thank you, Joan G