After 10 years of being on prednisone and then 10 off, I just had to do a 2 month bout of it starting at 60mg and tapering off. This time I had very few issues with swelling and weight gain for 2 reasons. I was prepared this time! So I only ate a LOW sodium diet. That was a huge help. I also took Young Living Essential oils Grapefruit and their Spearmint. Young Living is the ONLY essential oil you can ingest. Do NOT buy a crappy one at the store. The grapefruit is a diuretic and the spearmint is specifically supposed to help with Cushings Syndrome, which is what you develop on prednisone. I was amazed and very happy this time. Now hoping to not be on it ever again! Good luck to everyone. (I usually just put a drop of the EO under my tongue or I added it to water and drank it. Not the grapefruit and spearmint together as that would have tasted bad!)
I do not know your medical history but they may run other tests to check kidneys, heart etc to rule out any other potential causes.
p.s.- I'm on prednisone (tapering down from 40-on 15 now) and the swelling, insatiable hunger and the blurred vision in one eye is getting less and less every day. One important thing I do is drink a nauseating amount of water every day. At least one bottle, 16.9 oz., every hour or two. Keep the body hydrated and continuously flushing. The meds do their job but don't stick around longer than they have to. Again, as with any advice from a non-professional (me), run it by your dr.
Good Luck!!!