Figure 3

Search for ILD etiology in children. ILD is defined by the presence of diffuse infiltrates on chest radiographs or chest high resolution computed tomography, and abnormal pulmonary function tests with evidence of a restrictive ventilatory defect (in older children) and/or impaired gas exchange. The search for etiology requires a systematic step-by-step diagnostic strategy for identifying: exposure-related ILD; systemic disease-associated ILD; alveolar structure disorder-associated ILD; and ILD specific to infancy.