BackgroundThis study investigated clinical and laboratory characteristics of human bocavirus type 1 (HBoV1)‐plastic bronchiolitis (PB), Mycoplasma pneumoniae (MP)‐associated plastic bronchitis (PB) and MP‐NPB in children, highlighting inflammation, coagulation, and bronchoscopic needs.MethodsData on preschool children with PB during HBoV1 or MP infection were collected, comparing MP‐PB to severe Mycoplasma pneumoniae pneumonia.ResultCompared with the MP‐PB group, the HBoV1‐PB group, with younger children, had significantly milder clinical symptoms but higher WBC counts (p = .028). The MP‐PB group exhibited notably elevated Fibrinogen (p = .045) and d‐dimer levels (p < .001). When contrasting the MP‐PB with the MP‐NPB group, children in MP‐PB group still had higher levels of d‐dimer and increased inflammatory indicators such as C‐reactive protein, procalcitonin, lactate dehydrogenase, and interleukin‐6, which were significantly elevated compared with the MP‐NPB group. MP‐PB showed a higher prevalence of plastic bronchial casts in lower lobes (p = .016) and a dominance of neutrophils in BALF cytology. Additionally, children in the MP‐PB group tended to undergo a greater number of bronchoscopies.ConclusionThis study identifies key differences in plastic bronchitis in children due to HBoV1 and MP, highlighting HBoV1's milder inflammation in younger kids and MP's link to severe inflammatory and coagulation responses, guiding clinical diagnosis and treatment.