Hi Rdaddy,
My daughter's case is as follow:
She got fever on and off and finally consulted Dr. Leung Yun in Manning Building in Central (there is a discussion in this section). He listened my daughter's chest carefully and referred to have x-rays in Melbourn Building and analysed that my daughter got asthma. Acturally, my daughter's cough is not that kind of serious, but Dr. Yeung Yun is recommended to take "Singulair 4 mg" in controlling her asthma.
Dr. Leung Yun is a good doctor even the nurses, they are really really in patient to explain to you.
By the way, how long did your son have "Singlulair 4 mg", any side effect, how long your doctor prefer him to take and how much you buy
Many thanks