Thanks for following up. You should understand, that nasal polyps grow only in inflamed tissue of the nasal mucosa. The mucosa is wet. During an infection or allergic reaction, the nasal mucosa becomes loose, swollen and red, and produce fluid that drips out. With continued irritation, this mucosa may form a polyp. Although some people can develop polyps with no previous nasal problems,because they have hereditary tendency for develop polyps. often there is a trigger for developing polyps. These triggers include: -chronic sinusitis - bronchial asthma - allergic rhinitis -cystic fibrosis -Churg-Strauss syndrome with high level of Ig E -NSAID sensitivity (an allergy-like response to aspirin, ibuprofen They checked your son for allergy and cystic fibrosis, in addition i propose to check him for infection and do throat culture for flora and sensitivity to antibiotic . If they will find something, then treat inflammation in the nose Be healthy Dr.Svetlana