How did you know that it was the dairy causing the problem?
When I switched Liebs to goat milk, the pain stopped within a few hours - even now I can tell if he has had cowmilk products.
Was it an immediate or delayed reaction?
Within about 24 hours
Did you get allergy testing or any other medical consultation to confirm?
Tried to, but as it's an intolerance not an allergy (known, my dad and I both grew out of cowmilk intolerance) they wouldn't test for other things I didn't know about.
How did it impact your introduction to solids?
This happened post-solids as I'm a bad mummy who let her baby scream in pain for hours and hours without cutting dairy for 20 months.
Did your child grow out of the allergy or become able to tolerate small amounts?
Dad and I grew out of it so Liebs should - going to test him with it when he gets his big teeth. He's had pain from some accidental dairy recently so hasn't grown out of it yet, but it's impacting him less.
If your child had to maintain a dairy free diet, did you have to increase the intake of other foods to ensure they got appropriate calcium and nutrients?
He's on goat milk and soy products - and doing really well on them.
And while breastfeeding, did you alter your own diet for the same reasons? I'm taking calcium sups but suspect I should probably be modifying my diet in other ways.
Yeah, next baby I'll be goat from my BFP until weaning.

FWIW, I really enjoyed goat products while pg, more so than normal. Should have been a hint, in hindsight. But my mother never changed my diet, so I didn't know about goat until my grandmother told me she'd done it for dad.