i’ll be honest idk. Lactose is a sugar in milk (and by extension milk products) that some people can’t digest. so it’s not really an allergy iirc? but it causes stomach/digestive discomfort and it sucks

a milk protein allergy is just me being allergic to some of the proteins in milk. idk what exactly they are. but my symptoms are different than lactose intolerant people because in my case, it’s an actual allergy. specifically i break out in itchy hives.

fun fact: lactaid, a brand of milk for lactose intolerant people that’s had the lactose removed, is still unsuitable for me because the proteins are still there! i have to have soymilk or almond milk etc