a bad cough can be related as asthna?

my child is 2 1/2 and is cough very badly , doctor says its an allergy . I just can''t understand, his cough is getting worse day by day n also has a runny nose and was having fever too. I have asthma in my family and i am worried as he is having a whooping cough .
please please reply soon .

[jamlws]

Not sure if your still watching this post but with my son his allergies make his asthma so much worse and when he gets a cold. With his asthma he gets this dry cough that he isn't coughing anything up but he can't quit coughing. He is on breathing treatments when his asthma is acting up. If I was you I would try a allergy med that his dr tells you to give him and see if it helps and if not and he is still coughing alot get a 2nd dr to look him over. My son has great drs that take care of him cause he has so many health problems and I trust everything they tell me to do for him.
Jamie