Besides surgery, what could be done for nasal polyps in a 16 year old girl? what could potentially cause this?

Depending on severit: If the polyps are very severe surgery may be the best option. Nasal steroid sprays may also be helpful if the polyps are not too severe. Oral steroids have been used temporarily some times successfully, but should be used only short term and only if other methods are not in order. The polyps come from the lining of the sinuses. The mucosa becomes thickened and hypertrophied.