[The eosinophilic lung].

Infiltration of the pulmonary parenchyma by eosinophils is revealed in bronchoalveolar washings. Associated with pulmonary biopsy, this technique has renewed the approach to a classical syndrome. Pulmonary infiltration eosinophilia has multiple etiologies: some are well characterized (parasitic or medicinal), some others pose some nosological or etiopathogenic problems not yet clarified (chronic pulmonary infiltration eosinophilia, vasculitis of the lung). In such difficult cases, use of surgical pulmonary biopsies has to be envisaged.