Eosinophilic airway inflammation is common in subacute cough following acute upper respiratory tract infection.

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). 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. 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. 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.

Lai K ，Lin L ，Liu B ，Chen R ，Tang Y ，Luo W ，Chen Q ... -  《-》

Increased S-nitrosothiol levels in nonasthmatic eosinophilic bronchitis compared with cough variant asthma.

Nonasthmatic eosinophilic bronchitis (NAEB) and cough variant asthma (CVA) are common causes of chronic cough. Both are characterized by eosinophilic inflammation in the airways. However, airway hyperresponsiveness, which is a characteristic feature of CVA, is not observed in NAEB. We hypothesized that endogenous bronchodilator S-nitrosothiol (SNO) levels are different between patients with NAEB and CVA. SNO concentrations in sputum supernatant were measured using a commercially available kit in 20 NAEB and 21 CVA patients. The mean sputum eosinophil counts and exhaled nitric oxide values were similar in patients with NAEB (12.4 ± 2.3%, 80.6 ± 8.1 ppb) and CVA (15.3 ± 3.7%, 97.7 ± 9.2 ppb). By contrast, SNO levels in the airway lining fluid of NAEB patients were substantially higher than those of CVA patients (87.1 ± 9.8 vs. 46.8 ± 4.8 μM; p < 0.05). SNOs may be an important factor in determining the development of airway hyperresponsiveness in the presence of eosinophilic inflammation.

Lee BJ ，Jeung YJ ，Lee JY ，Choi DC ... -  《-》

Eosinophilic airway disorders associated with chronic cough.

Niimi A ，Matsumoto H ，Mishima M 《PULMONARY PHARMACOLOGY & THERAPEUTICS》

Clinical features of eosinophilic bronchitis.

Joo JH ，Park SJ ，Park SW ，Lee JH ，Kim DJ ，Uh ST ，Kim YH ，Park CS ... -  《-》

[Eosinophilic bronchitis without asthma--an additional rare cause for chronic persistent cough (CPC)? A 30-year old patient with severe CPC due to eosinophilic bronchitis without asthma or hyperreactivity].

Kardos P 《-》