The signs and symptoms linked with CMPA, ranging from colic and reflux to constipation, diarrhea and crying, make diagnosis a real challenge. Every case of CMPA is also unique, so it helps to be aware of all the possible symptoms to look out for. There are three main categories of symptoms*, including skin, digestive and respiratory and also a fourth category of more general signs*. These signs or symptoms can appear immediately, i.e., within minutes up to two hours of ingesting cow’s milk, or after several hours or days, depending on the nature of the reaction.