We had one of the screaming ones. There was no sleep the four first months until we got the advice to try to give extra milk, maybe she wasn't getting enough food from breast feeding. Her skin started going all bumpy red/white everywhere the babyformula touched and the lips swelled up. Turns out she was milk protein allergic. After clearing out all possible sources of milk protein (Tip: It's in everything, even the things you would never imagine containing milk) her skin returned to normal and she was not screaming the whole time any more.

We had, on advice from a nurse, tried to rule out milk protein earlier by mother not drinking any milk. She did however not say that you have to do that for a very long time before you can see any results. Think it was at least three-four weeks until you could say if it worked or not.

Luckily the milk protein allergy grows away before 7 years old and she is perfectly fine with milk now.