I'd bank on the Prednisone. Years ago, I had a horrible time coming off of the 5 mg. dose - flu like symptoms. I ended up cutting it in 1/2 and then eventually shaving a little off of the 1/2. But I DID IT - it just took a while.
Tis the season for the itchy skin too, but like you said, lotion should resolve that.
Most reactions I have heard of are localized around the stoma, from direct contact with product.
Diagnosed with CD in 1979, many resections and meds
Perm Ileostomy July 1984 at Cleveland Clinic
Disease free since surgery