Is it safe to be on a few corticosteroids at the same time?

Maybe: I can't think of too many situations in which more than one steroid at a time is required, unless one is a topical (cream or ointment). If these medications originate from different doctors, you may have a problem. See your primary care physician to evaluate the complete medication list.

No!: I cannot think of a medical reason to on different corticosteroids at one time, either arthritis, or another autoimmune disease, unless they are administered by different modes!