Pulmonary capillaritis

**Definition:** Isolated pauciimmune pulmonary capillaritis is a small vessel vasculitis restricted to the lungs that may induce diffuse alveolar haemorrhage with dyspnoea, anaemia, chest pain, haemoptysis, bilateral and diffuse alveolar infiltrates at chest X-rays, without any underlying systemic disease. ANCA are frequently positive but could be negative.