Q&A: bloody, mucusy stools

Rachel's got a question that's stumping me:

"My daughter is almost 5 months old and has had frequent bloody andmucusy stools on and off since she was about 6 weeks old. She is exclusively breastfed.  Our pediatrician initially said it was dairy and soy protein from my diet, so I cut those out. It seemed to make no difference. I then cut out wheat, then eggs, until eventually the "top 8" allergens were out of my diet. Still no improvement. My pediatrician says to wait it out, and since my daughter is gaining weight, seems happy, and is meeting developmental milestones I shouldn't worry. I just don't feel right about this, and since we are creeping up on solids introduction age I really want to figure it out.  Do you have any suggestions? We are so at the end of our ropes here."

Yeah, I just can't imagine that having blood and mucus in your poop is something that should just be ignored, so I'm kind of shocked that your pediatrician is telling you not to worry. Something is definitely not right.

You've dealt with the most obvious things: dairy, soy, wheat, eggs, etc.

Is this ringing a bell with anyone? I'm trying to think backwards through what I'd suggest if it were an adult suffering from blood and mucus in the stool, but I'm not getting anywhere with that in my head, either.

Was your daughter ever given antibiotics? That's the only thing that's jumping immediately to mind.

Please jump in with ideas if this is sounding familiar to anyone.