The blood you see in the toilet looks like much more than it really is. In the vast majority of cases, you do not need to worry about
getting emergent medical care because of blood loss due to bloody diarrhea.
The most pressing concerns (ie reasons you might go to the hospital) associated with UC are dehydration that cannot be managed at home or suspected toxic megacolon or intestinal perforation. Your daughter should be peeing a few times per day and when she pees it should come out pale yellow. If she isn't urinating, or if she has tachycardia (>100 heartbeats per minute) in addition to urinating very little, she probably needs to go to the ER to get IV hydration.
If her belly is distended (swollen), hard to the touch (as opposed to soft), and/or if she is running a moderate fever (>100 F), these can be signs of toxic megacolon and she should be taken to the ER.
Other than that, it's usually best to rest at home.
dx'ed UC pancolitis 5/12
past meds: asacol hd, VSL#3, apriso, rowasa, xifaxan, 6mp, cortifoam, pentasa, cimzia, canasa, butyrate, flagyl, cipro, prednisone, remicade, methotrexate, cholestyramine, cortenema
current meds: none!
step one: colectomy, end ileo 1/16/13
step two: j-pouch construction, loop ileo 5/1/13
step three: takedown 7/31/13