A 27-year-old man presented with relapsing vascular limb purpura, pulmonary infiltrates and cranial nerve palsies occurring after exposure to pigeons. A lung biopsy specimen showed Churg-Strauss angiitis. Actinomycetes were observed in pneumocytes. The circumstances preceding clinical manifestations and pathologic findings favored the diagnosis of pulmonary vasculitis as a consequence of inhaled antigen. Recovery was obtained after treatment with prednisone, cyclophosphamide, and plasma exchanges.