Hi...perihilar infiltrates need not be treated. It is a very common normal finding on chest xray or it can occur in any kid who s coming out of a viral illness. If the kid is active, no fast breathing, no feeding difficulty, no bluish discoloration of finger tips or lips.... You need not worry at all. Hope I have answered your queries. If can upload an image of the chest xray on this website to me, I will be glad to help you further. Regards - Dr. Sumanth