I am calling it quits on carrots. I had a funny feeling from the beginning, but pushed through because I truly wanted these to be a pass for Ellie. But no luck. Constipation can also be a sign of 'allergic' reaction, and after starting carrots the first time Ellie stopped her now regular stool. So I stopped, and then restarted, and this second time it took three days before we were seeing symptoms: ear drainage, raspy nose/chest, eczema flare, urping (wet burps), very fussy nights, and no stool.
The good news is it was a less severe reaction and took much longer to be sure. I believe this to be a sign of FPIES healing. Hooray! The bad news is now that she is on the road to healing, I think this might be one of those foods she may never be able to have. But we will shelve it for now, and come back to it in about 32 months.
The only remaining factor is that we still have not received the test results for sugar intolerance from her biopsy. This test is taking so long! Carrots are extremely high in sugar content, so we will see if those test results shed some light on this fail.
I am hopeful that she will recover quickly, and curious how long it will actually take to do so. Back to zucchini and onions, which is already great progress from where we were a short time ago!