title: Eosinophilic airway inflammation is common in subacute cough following acute upper respiratory tract infection.
abstract: OBJECTIVE
  Patients presenting with refractory postinfectious cough may respond to glucocorticosteroids but it is unclear whether airway eosinophilic inflammation exists in those patients. We aimed to determine the airway inflammation and causes of subacute cough following acute upper respiratory tract infection (AURTI).
  
  
  METHODS
  One hundred and sixteen patients with persistent cough lasting 3-8 weeks after upper respiratory tract infection were evaluated with differential cell count in induced sputum, spirometry and methacholine bronchial challenge testing.
  
  
  RESULTS
  In patients with subacute cough, sputum eosinophilia (median 8.5%,3.0-73.0%) was identified in 35 (33.6%) patients, 22 (18.5%) without bronchial hyperresponsiveness (BHR) were diagnosed as non-asthmatic eosinophilic bronchitis (NAEB), 13 (14.3%) of whom with BHR were diagnosed as cough variant asthma (CVA). Cough in patients with sputum eosinophilia improved after treatment with corticosteroids. Compared with postinfectious cough (PIC) and NAEB, CVA had significantly higher median eosinophil count in induced sputum (0.5% vs 7.5% vs 20.0%, P < 0.01). MMEF in CVA was significantly lower than PIC and NAEB (P < 0.05). The common causes of subacute cough following acute upper respiratory tract infection (AURTI) were PIC (37.8%), NAEB (18.5%), CVA (14.3%) and upper airway cough syndrome (UACS) (10.1%). Atopic cough (AC) (5.2%) and gastroesophageal reflux-related cough (GERC) (3.4%) were less common in subacute cough following AURTI, while 9 (7.8%) patients had unexplained cough.
  
  
  CONCLUSIONS
  Subacute cough following AURTI can be attributed to different entities, eosinophilic airway inflammation is common. Induced sputum should be considered when evaluating patients with subacute cough following acute upper respiratory tract infection.
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Kefang
authors.initials: K
authors.lastname: Lai
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Baojuan
authors.initials: B
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Ruchong
authors.initials: R
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D001249:Asthma / Q000150:complications / Q000175:diagnosis*; D016535:Bronchial Hyperreactivity / Q000150:complications; D001985:Bronchial Provocation Tests; D001991:Bronchitis / Q000175:diagnosis* / Q000382:microbiology; D002908:Chronic Disease; D003371:Cough / Q000382:microbiology / Q000473:pathology*; D004802:Eosinophilia / Q000175:diagnosis* / Q000382:microbiology; D004804:Eosinophils; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D012141:Respiratory Tract Infections / Q000150:complications*; D013183:Sputum / Q000166:cytology; D055815:Young Adult
keywords: Cough; Eosinophilic inflammation; Etiology; Postinfectious cough; Upper airway infection