Usually the first flare is the worst because of the time it takes to diagnose it and the medicines that we take are typically slow acting. Loss of appetite is normal and at some point (a few weeks) the steroids might kick in and change his appetite to become ravenous (common side effect of steroids).
How old is your son? Is he seeing a pediatric GI or a regular GI? If I could give one piece of advice to a newly diagnosed patient/parent it would be to find a GI who specializes and specifically focuses on IBDs. Once I started going to an IBD specialist my health improved. Most GIs don't deal with IBDs on a regular basis, they are good at c-scopes, diverticulitis, etc but IBDs can be complex and it's best to find a GI capable of relating to your son issues and treating him. You'll find IBD specialists at most universities and teaching hospitals.
Steroids are the IBD treatment with the worst side-effects and aren't a long term solution, you need to find a treatment to get him off them as soon as possible. Have you discussed biologicals like Remicade or Humira? They are well studied drugs and are very well tolerated.
DX'd with Severe Pancolitis June 2005
Previous Meds: 5ASAs, Predisone, 6-MP. Remicade, Humira, Simponi, Cimzia & Cyclosporine
3-step J-Pouch surgery: 2013 & 2014
Current Condition: Chronic Pouchitis -- Not as bad as I thought it would be
Current Meds: Stelara
Total Hip Replacement: 12/16 -- Thanks Prednisone!!!www.healingwell.com/community/default.aspx?f=38&m=3755226