[Unilateral choanal atresia: a missed diagnosis].

Bilateral choanal atresia is a congenital anomaly usually diagnosed at birth. In contrast, unilateral atresia causes variable degrees of nasal stuffiness and discharge that might mask the diagnosis and delay the proper treatment. We present five cases of unilateral atresia in which the correct diagnosis was delayed and erroneous treatments were instituted--two adults who had undergone unnecessary septal and turbinate surgery, two older children who were treated medically and one patient who was treated for epiphora. Insufficient awareness of this entity occurring in adults and older children and other possible causes of diagnostic error are discussed. A unilateral mucoid or watery rhinorrhea and obstruction, that lasts from early childhood without evidence of sinusitis and not responding to any medical treatment, should alert the physician to consider unilateral atresia and to perform endoscopic and computed tomography examinations at an early age. Careful interpretation of the computed tomography scan including the axial planes is required.