Case 1 : A 70-year old female came to our clinic complaining uncontrolled asthma for 10 years. Spirometry showed obstructive lesion (FEV1=94.9%, FEV1/FVC =71.08%) with 5% bronchodilator (BD) response. PC20 of methacholine was 3.8 mg/ml. Chest CT showed diffuse bronchial wall thickening with tree in bud sign. Treated with clarithromycin for 1 month, FEV1was improved from 64.9% to 84.2% without asthma medication.
Case 2 : A 52-year old male complained his uncontrolled asthma for 4years. He was diagnosed as severe asthma and treated at other hospital. His FEV1 was 1.74L (54.4%) and improved 20.6% after bronchodilator. CT scan showed diffuse bronchiolitis thus we adminster clarithromycin for 6 months. FEV1was improved from 54.4% to 95.3%. He could discontinue inhaled corticosteroid and other asthma medications.
Case 3 : A 25-year old male with uncontrolled asthma. Initial FEV1 was 2.51 L (62.6%) and severe sputum eosinophilia. His CT scan shows diffuse bronchitis with tree bud sign and then treated with clarithromycin for 9 months. FEV1was improved from 62.6% to 88.4%. He reduced daily amount of inhaled corticosteroid.
Case 4 : A 60-year old female was visited to our clinic with severe asthma. Spirometry showed obstructive lesion (FEV1=42.9%, FEV1/FVC =73.37%) without BD response. CT scan shows diffuse bronchial wall thickening. FEV1was improved from 42.9% to 97.1 % after 6 months use of clarithromycin without any asthma medication.
Conclusion: We report 4 cases of DPB were mistaken for severe asthma or combined with asthma. We suggested DPB must be considered as a differential diagnosis for treatment resistant asthmatics in Korea.