Experimental: Infliximab

Patients randomized to this arm will receive IV infliximab regardless of whether they are hospitalized due to their colitis.~* Infliximab: Predetermined dose of intravenous infliximab, up to 3 times over 7 weeks~* Crossover for inadequate response: Patients who do not respond to initial treatment within 3 days with a decrease in symptoms by one grade, or who do not improve to grade 2 or less symptoms by 5 days will add combination therapy from the other treatment arm (corticosteroids) at full initial dosing.

Experimental: Corticosteroids

Patients randomized to this arm will receive IV steroids or oral steroids depending on whether the severity of their colitis requires hospitalization (inpatient).~* Inpatient: Predetermined intravenous dose of methylprednisolone, 2x daily up until patients can safely be transitioned to an oral prednisone taper~* Outpatient: Predetermined oral dose of predisone, daily over 7 weeks~Crossover for inadequate response: Patients who do not respond to initial treatment within 3 days with a decrease in symptoms by one grade, or who do not improve to grade 2 or less symptoms by 5 days will add combination therapy from the other treatment arm (infliximab) at full initial dosing.