Chronic otitis media: the significance of nasal obstruction. The nasal airway resistance of 15 patients with unilateral chronic otitis media and 15 controls was measured by anterior active rhinomanometry. Airway resistance was measured on each side before and after decongestion to differentiate resistance due to structural abnormality from that due to mucosal swelling. The nasal resistance was significantly greater (P less than 0.01) on the side of the affected ear in patients with unilateral chronic otitis media before decongestion, but following decongestion the difference was not significant. Nasal obstruction is a significant determinant in unilateral chronic otitis media and although septal displacement may be the underlying cause, the major component of the obstruction appears to be due to an associated mucosal oedema. 