Hello.
Thank you for asking at HCM.
Morning cough with small sputum, sneezing, nasal itching and irritation, etc are common signs of allergic respiratory disease. It can be an
allergic rhinitis, sinusitis or sometimes
childhood asthma.
I understand your concern about pulmonary
hypertension as his sister had it. But it is not a very common disease in children.
So first of all I would suggest you to consult an Allergist who will examine your son in detail and suggest you tests like CBC, AEC, total IgE and allergy testing. If he has more of morning symptoms, personally I would like to test him for allergy to house dust mite, indoor molds, cockroach allergens and pet dander allergens (if you have a pet).
If these tests suggest allergic disease, I would suggest him to take regular
montelukast and an antihistamine like
levocetirizine. Also, the allergist will also suggest him some allergen control measures depending on allergy testing result, and if possible,
allergen immunotherapy.
If he has other long term health issues (as you have mentioned "poor health"), I would suggest you to
consult a pediatrician first who can examine him in detail and suggest investigations to come to a diagnosis.
Hope this will be helpful to you.
Wish your son the best of health.
Regards.