Objective: To review clinical, laboratory, and outcome characteristics of chi ldren diagnosed with pulmonary capillaritis (PC), a small- vessel vasculitis, p resenting as diffuse alveolar hemorrhage (DAH), and to compare these findings wi th those for children with other alveolar hemorrhage syndromes. Study design: A retrospective chart review of patients who underwent a lung biopsy because of a clinical suggestion of pulmonary hemorrhage. Results: PC was identified in 8 of 23 patients. In these patients, cough, crackles, and hypoxia were common. Alveol ar infiltrates on radiography and anemia were present in 7 of 8 cases. Serologic evidence of a systemic vasculitis was present in 50% of patients. High- dose corticosteroids proved effective in controlling alveolar hemorrhage in all cases . There were no presenting signs or symptoms that could differentiate patients w ith PC from those with non- immunemediated alveolar hemorrhage. In general, pat ients with PC had a lower hematocrit and higher erythrocyte sedimentation rate ( ESR). Conclusion: Children presenting with lower respiratory tract symptoms, che st x- ray abnormalities, and anemia should undergo evaluation for PC, as early initiation of immunosuppression can be lifesaving and organ sparing. No clinical signs to differentiate immune and non- immune- mediated alveolar hemorrhage w ere evident in this study. Objective: To review clinical, laboratory, and outcome characteristics of chi ldren diagnosed with pulmonary capillaritis (PC), a small-vessel vasculitis, p resenting as diffuse alveolar hemorrhage (DAH), and to compare these findings wi th those for children with other alveolar hemorrhage syndromes. Study design: A retrospective chart review of patients who underwent a lung biopsy because of a clinical suggestion of pulmonary hemorrhage. Results: PC was identified in 8 of 23 patients. In these patients, cough, crackles, and hypoxia were common Alveol ar infiltrates on radiography and anemia were present in 7 of 8 cases. Serologic evidence of a systemic vasculitis was present in 50% of patients. High- dose corticosteroids proved effective in controlling alveolar hemorrhage in all cases. symptoms that could differentiate patients w ith PC from those with non-immunemediated alveolar hemorrhage. In general, pat ients with PC had a lower hematocrit and Conclusion: Children presenting with lower respiratory tract symptoms, che st x-ray abnormalities, and anemia should undergo evaluation for PC, as early initiation of immunosuppression can be lifesaving and organ sparing. No clinical signs to differentiate immune and non-immune-mediated alveolar hemorrhage w ere evident in this study.