In idiopathic interstitial pneumonia, the incidence of pestle finger is not high and not all types of patients can develop pestle finger. It is mainly seen in idiopathic pulmonary fibrosis, non-specific interstitial pneumonia fibrosis type, idiopathic pulmonary pleural elastosis, airway central interstitial pneumonia and other types that can lead to destruction of lung structure and hypoxemia, but of course other types can appear but are rare. There is no clear percentage, but in idiopathic pulmonary fibrosis, past data reported pestle fingers in about 25-50% of patients.