Hypersensitivity Pneumonitis in Türkiye: An Underrecognized Pulmonary Disorder

Abstract

. Introduction: The aims of this study are to investigate hypersensitivity pneumonitis (HP) related publications from T & uuml;rkiye, to discuss features of HP concerning our case series, and to evaluate our patients in terms of diagnostic confidence according to existing guidelines. Methods: We conducted a comprehensive review of the literature to analyse cumulated data about HP publications originating from T & uuml;rkiye. Additionally, we evaluated HP cases diagnosed and followed in last 5 year at our hospital. Results: A total of 34 HP-related publications originated from T & uuml;rkiye. Thirteen articles reported pediatric cases, while 20 articles included adult patients. Bird fancier's disease was the most common etiology of HP. A total of 138 patients were included in this study. Of these, 107 (77.5%) were female, and 31 (22.5%) were male. According to the American Thoracic Society (ATS) 2020 guidelines, 45 patients (33%) had a definite diagnosis, whereas 94 patients (68%) were diagnosed as definite cases according to the American College of Chest Physician's (ACCP) 2021 guidelines. Eighty-five patients (62%) had the non-fibrotic form, while 53 patients (38%) had the fibrotic form. The most frequent etiology was barn located beneath houses in rural areas (58 patients, 42%). Conclusion: This study highlights that HP, although underrepresented in Turkish medical literature, is more prevalent than previously recognized. Barns located beneath houses in rural areas and moldy environments in urban settings are the two main etiologies of HP in our region. The high prevalence of chronic cases in our patient group highlights the difficulty of diagnosing HP at early stages. We propose refining HP classification into "chronic inflammatory" and "chronic fibrotic" subtypes and advocate for a pragmatic diagnostic approach that avoids unnecessary invasive procedures in patients with identifiable antigens and characteristic HRCT findings.