Table 1 Classification of chILD in children older than 2 years of age by etiology and frequency of different category (N=133)

 Hypersensitivity pneumonitis

N=10 (7.5%)

 Drug-induced hypersensitivity reaction

N=2 (1.5%)

 Recurrent aspiration

N=6 (4.5%)

 Connective tissue diseases

N=12 (9.0%)

  Juvenile dermatomyositis

N=7

  Juvenile idiopathic arthritis

N=3

  Systemic lupus erythematosus

N=2

 Interstitial pneumonia with autoimmune features

N=9 (6.8%)

 Vasculitis

N=14 (10.5%)

 Primary immunodeficiency diseases associated ILD

N=13 (9.8%)

  STING–associated vasculopathy with onset in infancy

N=3

  COPA syndrome

N=1

  Cytotoxic T-lymphocyte associated protein-4 deficiency

N=1

  STAT3 mutation

N=1

  Autoimmune lymphoproliferative syndrome

N=1

  Chronic granulomatous disease

N=3

  Common variable immunodeficiency disease

N=1

  Inflammatory bowel disease with neutropenia

N=1

  Combined immunodeficiency disease

N=1

 Langerhans cell histiocytosis

N=7 (5.3%)

 Metabolic diseases

N=9 (6.8%)

  Methylmalonic acidemia and homocysteinemia

N=7

  Niemann-Pick disease

N=2

 Malignant infiltrates

N=2 (1.5%)

  Lymphoma

N=1

  Pulmonary metastases from thyroid carcinoma

N=1

 Surfactant dysfunction disorders

N=5 (3.8%)

  SFTPC mutation

N=3

  ABCA3 mutation

N=2

 Diffuse alveolar hemorrhage with no proof of systemic disease

N=27 (20.3%)

 Cryptogenic organizing pneumonia

N=4 (3.0%)

 Diffuse pulmonary lymphangiomatosis

N=3 (2.3%)

 Pulmonary hypertensive vasculopathy

N=2 (1.5%)