all of the above is true, but there could be something else causing these symptoms.
sounds like an allergy of some description, does he have a cat or dog?
i dont know how old she is, but is there a chance she could be athsmatic? i dont mean to worry you, my neice had same probs and her mum was always taking her to doctor and thet kept giving her antibiotics until her mother put her foot down, went to another doctor who diagnosed mild asthma, and hayfever, gave her a puffer and an antihistamine, she was fine.
best bet to see a doc, if you havent already.
xxx starry sky