I have RA and in the middle of a scabies fight. When ever I take prednisone the red spots and itch get worse. I gave myself a scabies treatment on the 24 no spots started predation on 26 and have smooth red marks on legs and arms. Back in Jan. I took prednisone had had a rash I thought it was an allergic reaction. In April I realized it was scabies. Why does the prednisone bring the rash out.