Objective To enhance the understanding of nonfibrotic hypersensitivity pneumonitis (nfHP) by summarizing the clinical characteristics of 32 cases of nfHP. Methods The data of 32 cases with nfHP was collected and analyzed. They were diagnosed in Beijing Friendship Hospital, Capital Medical University from Jan 1st, 2017 to Oct 31, 2021. Results The median age of the nfHP patients was 54 years, among whom 75.0% were females. The cases developed in a majority of avian exposure (22 cases, 68.8%). The main symptoms were dyspnea/shortness of breath (28 cases, 87.5%), cough (25 cases, 78.1%）and sputum production (21 cases, 65.6%). High-resolution CT (HRCT) showed diffuse ground glass opacification (25 cases, 78.1%), centrilobular ground glass nodules (20 cases, 62.5%) and air trapping (9 cases, 28.1%). Bronchoalveolar lavage fluid (BALF) featured an increase of proportion of lymphocytes (>20%, 90.6% and >40%, 50%), and a decrease of CD4+/CD8+ T cell ratio (<1.2, 65.6% and <0.8, 40.6%). Most of the cases had reduced diffusion capacity for carbon monoxide (16 cases out of 26 cases, 61.5%) and decreased total lung capacity (13 cases out of 26 cases, 50%). Few cases showed obstructive ventilatory function (6 cases out of 26 cases, 23.1%). Most cases (22 cases, 68.8%) of nfHP showed an excellent survival with short-term corticosteroid treatment. Few cases (5 cases, 15.6%) experienced spontaneous remission after antigen avoidance. Conclusions The diagnosis of nfHP includes identifying antigenic exposures, featured chest HRCT and lymocytosis in BALF. nfHP patients showed an excellent survival with short-term corticosteroid treatment as well as antigen avoidance.
