Talk to Pediatrician on Chest Allergy

My daughter has chest problem since she was 4 month old.she suffered in pneumonia when she was 4 month old.and after that when was weather changes came she became ill mostly in winter.dr daignosis chest allergy.and this problem still present... please doc how canI prevent my child from this problem..I own myself gave her any antiallergic when I notice cough allergic condition....