I would also agree - you need scopes to see how bad things are. It's good to "see" what is going on before trying something - that way, when you re-scope you'll have some idea of how much things have changed. And it may change the treatment plan - if there is a LOT of inflammation, they generally go straight to biologics now.
Like others have said, 6MP/Imuran are being used less and less now. Methotrexate is used instead. It is either a shot or pills. The shot has a teeny-tiny needle and is not painful. It is given once a week. Some kids have nausea with it, but Zofran and folic acid can be used to minimize side effects.
In terms of biologics, usually they start with Remicade or Humira. Remicade is an infusion given every 4-8 weeks. Humira is an injection given every 2 weeks (can be given every week if necessary). Remicade tends to work more quickly and is usually preferred by kids because Humira is painful. With Humira it is the actual medication that burns, not the needle. There are things you can do to reduce the pain if that's what the doctor chooses.
While you are waiting for her maintenance medication to kick in, EEN or steroids are good options. If she's willing to do EEN again, I'd go with that.
My daughter was already on biologics when she was diagnosed with Crohn's, since she had already been diagnosed with juvenile idiopathic arthritis. Her JIA was under-treated and we watched her get sicker and sicker and progress from just a few joints to almost every joint in her body being involved. Her JIA went from moderate to severe
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So once she was diagnosed with Crohn's, we wanted to treat it aggressively to prevent complications. Her GI put her on Remicade and MTX. It took about 3-4 infusions before she was feeling better. 8 months later, we redid scopes and they were MUCH better. ALL the ulcers in her colon were gone, the granulomas seen on biopsies were gone too. In fact, her colon looked "perfect" - like she didn't even have IBD. She still had mild inflammation in her terminal ileum, but it was also much better.
Good luck!