3 year old son seems to have a fruit intolerance, anyone going through the same thing?

My son seems to have a sensitivity to fruit, mostly berries and the more tart ones. He will poop all day (soft stools mostly) if I let him have a bowl full of berries, so I've cut them out of his diet and just do bananas and watermelon. Last night I let him have a small slice of mango keylime pie, since we were all having some and I didn't want him to feel left out. Big mistake. His daycare just called me and said he had explosive diarrhea and his butt and thighs are all red and irritated. It must be the pie I'm assuming? But here's the weird part. He's had diarrhea going on for over 2 weeks now, according to his daycare. I've made it a point to pack his lunches with bland things like crackers, PB&J sandwiches or egg salad sandwiches, honey graham crackers, etc. and the diarrhea was still going on so we figured it must be viral. Aside from the diarrhea, he was acting fine. No fever, still eating, still in a good mood. But last week he was complaining of stomach pains so I took him to the doc right away, and they told me to get a poop sample and they would test it for parasites and bacteria. I just got those results this morning and it was negative. AND, he didn't poop all weekend until Sunday morning and he happened to be with my mom but she said it wasn't watery diarrhea and was more normal. I was so happy, I figured whatever it was, was finally going away. But then he just had watery diarrhea again at school this morning, and I'm attributing it to the pie last night. But then why was he having watery diarrhea all last week and the week before at school with no fruit in his diet?This is so frustrating! I called his ped and left a message for her to call me back and discuss. Maybe it's both? He had a viral thing going on and then the keylime pie last night?One more thing, a few times he has pooped in the toilet, I noticed his poop was really skinny so I'm thinking inflammation too. Is it common for toddlers to be sensitive to fruit like this? Will he outgrow it? He loves fruit so much.Any advice is greatly appreciated. via /r/Parenting http://ift.tt/2q3hAsQ