A pilot study for Basidiomycete-associated chronic cough: A potential contributor to refractory and unexplained or refractory chronic cough

Recent evidence suggests a potential association between chronic cough and environmental fungi, particularly basidiomycetes, giving rise to the concept of fungus-associated chronic cough (FACC). However, the role of basidiomycetes in chronic cough remains poorly understood. In this pilot study, we investigated 30 patients with unexplained or refractory chronic cough (UCC/RCC) and 30 patients with other respiratory diseases (non-chronic cough). Spontaneous sputum samples were collected for fungal culture, and participants completed a cough and sputum symptom questionnaire, underwent chest computed tomography, and were evaluated for underlying diseases and medication use. Analyses were conducted by chronic cough status and by basidiomycete detection. Basidiomycetes were detected in the sputum of 9 out of 30 chronic cough patients but in none of the non-chronic cough patients (P = 0.0019), with a significant seasonal peak from June to August (P = 0.0419). No associations were observed with age, sex, underlying diseases, cough severity, or high-resolution computed tomography findings. These results indicate that basidiomycete colonization may contribute to FACC in individuals with UCC/RCC, particularly during the summer months.