Recent studies about the use of Traditional Chinese Medicine (TCM) to treat cough variant asthma (CVA) , a common respiratory disease, are increasing. TCM has proven to be effective in improving symptoms and the overall treatment efficacy of CVA, but relevant research is still in the exploratory stage, and there are no unified and standardized diagnostic criteria for CVA.

To explore the common syndromes and symptom characteristics of CVA.

The literature related to CVA syndromes or symptoms treated by TCM was searched in CNKI, Wanfang Data, VIP, and SinoMed databases from inception to October 2, 2021. SPSS 25.0 software was used to support the input of extracted information to establish a database, and the statistical treatment of the frequencies of CVA-related syndromes and symptoms. The symptoms with a frequency over 5% were selected for factor analysis, and the common factors were extracted for further hierarchical cluster analysis, and the potential syndromes were inferred from the results. Using Lantern 5.0 software, based on the LTM-EAST (Latent Tree Model-Extension Adjustment Simplification until Termination algorithm) , a latent structure model was constructed and a comprehensive cluster analysis was performed to infer potential syndromes. Then the common syndromes and symptom characteristics of CVA were obtained by combining the results of frequency statistics, hierarchical clustering, and latent structure analysis.

A total of 621 studies were included, involving 115 symptoms, including cough, pharyngeal itching, low sputum volume, etc. Thirty-nine syndromes were involved, among which the highly frequent syndromes were pathogenic wind invading the lung, wind and cold invading the lung, and lung yin deficiency. Six potential syndromes were derived from hierarchical cluster analysis, including wind and heat invading the lung, liver fire invading the lung, lung qi deficiency and so on. The latent structure analysis was performed on the symptoms with frequency over 3%, by which 21 latent variables, and 42 latent classes were obtained, and 12 potential syndromes were further inferred by comprehensive clustering, including pathogenic wind invading the lung, wind and cold invading the lung, wind and heat invading the lung, and so on. Based on the above analyses, 11 common syndromes were finally identified. Each syndrome has specific symptom characteristics, for example, the syndrome of pathogenic wind invading the lung manifests itself as cough, sneezing, running nose, and nasal congestion.

We identified 11 common syndromes of CVA with typical symptom characteristics, which are pathogenic wind invading the lung, wind and cold invading the lung, wind and heat invading the lung, wind and dryness damaging the lung, phlegm and heat congesting in the lung, phlegm and dampness accumulating in the lung, liver fire invading the lung, cold fluid retention in the lung, lung qi deficiency, lung yin deficiency, and lung-spleen qi deficiency. Our analysis will provide a basis for clinical syndrome differentiation and clinical investigation of CVA.

咳嗽变异性哮喘（CVA）是呼吸系统常见疾病，近年来，中医药治疗CVA的相关研究逐年增多，中医药在提高疗效、改善症状等方面具有一定优势，但仍处于探索阶段，尚未形成统一规范的证候诊断标准。

初步探究CVA常见证候及其症状特征。

计算机检索中国知网（CNKI）、万方数据知识服务平台、维普网（VIP）、中国生物医学文献服务系统（SinoMed）中涉及CVA证候或症状的相关文献，检索日期为建库至2021-10-02。采用SPSS 25.0软件提取相关信息以建立数据库，并对证候、症状进行频数统计；选取频率>5%的症状进行因子分析，提取公因子进行系统聚类分析，根据结果推断潜在证候；采用孔明灯Lantern 5.0软件，基于双步隐树分析LTM-EAST算法，构建隐结构模型并进行综合聚类分析以推断潜在证候。综合频数统计、系统聚类以及隐结构分析结果，得到CVA常见证候及其症状特征。

共纳入文献621篇，涉及症状115个，包括咳嗽、咽痒、痰量少等；涉及证候39个，频率较高的有风邪犯肺证、风寒犯肺证、肺阴虚证等。系统聚类分析推断出6个潜在证候，包括风热犯肺证、肝火犯肺证、肺气虚证等。对频率>3%的症状进行隐结构分析，获得隐变量21个，共计42个隐类，进一步综合聚类推断出12个潜在证候，包括风邪犯肺证、风寒犯肺证、风热犯肺证等。综合以上分析结果最终确定11个常见证候，各证候具备一定症状特征，如风邪犯肺证包含咳嗽、喷嚏、鼻流涕、鼻塞等症状。

CVA常见证候有11个，分别为风邪犯肺证、风寒犯肺证、风热犯肺证、风燥犯肺证、痰热壅肺证、痰湿蕴肺证、肝火犯肺证、寒饮伏肺证、肺气虚证、肺阴虚证和肺脾气虚证，各证候的症状特征显著，可为临床辨证提供参考，为临床调查研究提供依据。