My friend just found out her dd is allergic yesterday. She kept breaking out in hives and rashes. It took a while before they figured out that is what it was.
Bad diaper rash (around his little hole), excema, dark circles under his eyes, bloated and very very gassy and then eventually crying after he ate. It took 2 docs and 3 months for ME to finally figure it out. Once I cut it out of my diet everything went away. (and returns if he eats something with dairy)
DD's daycare accidentally gave her a full glass of milk when she was only 11 months (there was a sub in the room that day who made the mistake.) That night she was HORRIBLY fussy, screaming bloody murder. Normally bedtime was peaceful and she would just nurse and drift off, but she was flailing, screaming and freaking out. Then all of a sudden she threw up EVERYWHERE. We tried milk again when she was 15 months and she got a distinct rash on her arms. She still gets a rash on her arms if she gets cows milk (though cheese and yogurt do not give her a rash, just whole milk and I even tried 2% with the same reaction.)
Re: switched to cow's milk....suspected allergy