Clinical features of eosinophilic bronchitis.
BACKGROUND
Eosinophilic inflammation of the airway is usually associated with airway hyper-responsiveness in bronchial asthma. However, there is a small group of patients which has the eosinophilic inflammation in the bronchial tree with normal spirometry and no evidence of airway hyper-responsiveness, which was named eosinophilic bronchitis. The objectives of this study are 1) to investigate the incidence of eosinophilic bronchitis in the chronic cough syndrome and 2) to evaluate the clinical features and course of eosinophilic bronchitis.


METHODS
We evaluated 92 patients who had persistent cough for 3 weeks or longer. In addition to routine diagnostic protocol, we performed differential cell count of sputum. Eosinophilic bronchitis was diagnosed when the patient had normal spirometric values, normal peak expiratory flow variability, no airway hyper-responsiveness and sputum eosinophilia (> 3%).


RESULTS
The causes of chronic cough were post-nasal drip in 33%, cough variant asthma in 16%, chronic bronchitis in 15% and eosinophilic bronchitis in 12% of the study subjects. Initial eosinophil percentage in the sputum of patients with eosinophilic bronchitis was 26.8 +/- 6.1% (3.8-63.7%). Treatment with inhaled steroid is related with a subjective improvement of cough severity and a significant decrease of sputum eosinophil percentage (from 29.1 +/- 8.3% to 7.4 +/- 3.3%). During the follow-up period, increase in sputum eosinophil percentage with aggravation of symptoms were found.


CONCLUSIONS
Eosinophilic bronchitis is one of the important cause of chronic cough. Assessment of airway inflammation by sputum examination is important in investigating the cause of chronic cough. Cough in eosinophilic bronchitis is effectively controlled by inhaled corticosteroid, but may follow a chronic course.
Joo
Jae Hak
JH
Department of Internal Medicine, Soonchunhyang University College of Medicine, Seoul, Korea.
Park
Sang Joon
SJ
Park
Sung Woo
SW
Lee
June Hyuk
JH
Kim
Do Jin
DJ
Uh
Soo Taek
ST
Kim
Yong Hoon
YH
Park
Choon Sik
CS
D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001249:Asthma / Q000150:complications / Q000453:epidemiology; D001991:Bronchitis / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D019819:Budesonide / Q000627:therapeutic use; D002908:Chronic Disease; D003371:Cough / Q000453:epidemiology / Q000209:etiology*; D004802:Eosinophilia / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D013183:Sputum / Q000737:chemistry / Q000276:immunology
D000893:Anti-Inflammatory Agents; D019819:Budesonide