Allergies?? or More??

In the past couple weeks we've noticed a persistant cough in Brendan. He doesn't show any other signs of illness except this cough. Its worse at times when he is waking up from naps and in the morning. We can always tell he is going to wake up soon by the coughing. He also coughs frequently at night. I took him the dr. and he said it is probably allergies and to keep an eye on it. If it gets worse it could be a sign of asthma. We got a prescription for Zyrtec that we could fill if we wanted to. I wasn't going to but just in the past few days his cough has increased throughout the day. I hope it isn't asthma!! Maybe we'll try the medicine for a bit. I just hate giving the kids medicine if I don't have to.