My son caught strep at 4 months. Babies can get strep or pharyngitis, though its not super common. Mine cried non stop after the 2nd day and began refusing to eat (swallowing hurt, I'm sure) so since it was over the weekend I took him into the ER where they kept telling me he was just "teething."

I insisted that I wasn't going home empty handed, my baby was sick, and they sent me home with antibiotics. Monday when I followed up with his ped, he took one look in his mouth and DX'd him. Told me that it was one of the worst cases he'd ever seen in a child that young, and this was after 2 days of antibiotics! He said that my insistance that something was really wrong with him and getting the antibiotics saved him from being hospitalized that day. So go with your gut when it comes to stuff like that! They can't tell us what's wrong, but you know your baby better than anyone else and have to speak up for him!