My 4 month old has had croup 3 times in a 2 month span. can this be something else? if so, what should i be looking for?

Pattern illness: Croup is more a pattern than a specific germ.Like diarrhea or colds, there can be many agents involved. With the label so many times in a few months, i would wonder if the kid has a weakness in the walls of her/his airway or other structural reason that the croup sound is recurrent.An ENT can evaluate the airway and or sometimes a chest xray will show compression of the airway by aberrant artery.

Workup mgt: I agree that a structural change, including narrowing, collapsibility of the airway and external compression by a mass or vessel are also possible. Recurrent or persistent croup may occur as a result of an infection or secondary infection. Since your child has been treated with steroids to reduce swelling and is still symptomatic, I would recommend a referral, endoscopy and reimaging the airway.