OBJECTIVE: To describe pulmonary involvement in Henoch-Schonlein purpura (HSP). PATIENTS AND METHODS: We retrospectively reviewed the medical records of patients with HSP who were seen at the Mayo Clinic in Rochester, Minn, during a 6-year period (January 1, 1997, to December 31, 2002). Patients with HSP and pulmonary involvement were identified through a review of clinical records, radiological studies, pulmonary function data, and lung biopsy findings. RESULTS: We identified 124 patients with HSP during the study period; 72 (68.1%) were males. The median age was 15 years (range, 8 months to 81 years). Among the 124 patients with HSP, 3 (2.4%), all adults, had pulmonary Involvement. Of these 3 patients, aged 20, 67, and 76 years, 2 were women. Pulmonary manifestations consisted of diffuse alveolar hemorrhage (DAH) (2 patients) and usual interstitial pneumonia that improved with corticosteroid therapy (I patient). CONCLUSIONS: Pulmonary involvement In HSP is rare. It occurs more often In adults and commonly manifests as DAH and occasionally as usual interstitial pneumonia or Interstitial fibrosis. Our cases and previously reported cases suggest that DAH is the most common manifestation of pulmonary Involvement in HSP.