Postinfectious bronchiolitis obliterans masked by misdiagnosis as asthma.

Patients with PIBO who had initially been misdiagnosed with asthma were correctly diagnosed at older ages and had longer symptom duration. Asthma may mask PIBO diagnosis by the similarity of symptoms and the clinical response to inhaled β2-agonist or steroid treatment. PFTs may not help clinicians because of the age of children. The delay in the diagnosis of PIBO is probably attributable to the fact that some clinicians fail to include PIBO in the differential diagnosis when there is no clinical response to asthma medication.