Heidi Loncosky wrote:

Daniel has had problems that were spread out enough that we could never
connect them with a particular food.

We started with a gastroenterologist.
His first suggestion was a lactose free diet for two weeks.

A milk allergy can cause recurrent diarrhea, as well as a distended
abdomen, excessive belching, rectal gas, nausea, or vomiting, clucking
throat sounds, bed-wetting, ear fluid, nose congestion, asthma, leg
aches or personality changes.
" BINGO!

Dear Heidi,

"MILK, WHAT A SURPRISE!" (That's the slogan of the people with the
1-800-WHY MILK phone number)

Robert Cohen