[Eosinophilic lung in children].

Pulmonary eosinophilia is an anatomo-clinical entity in which pulmonary parenchymatous infiltrates are associated with tissue hypereosinophilia. Blood eosinophilia which is very frequent but not absolutely constant makes the diagnosis likely. Four case reports illustrating pathophysiological mechanisms show its reality in pediatrics as well as its etiological diversity: parasitosis (filariasis), allergic bronchopulmonary aspergillosis complicating cystic fibrosis, vasculitis (Churg-Strauss syndrome) and chronic pulmonary eosinophilia, the last diagnosis being a diagnosis of exclusion. Pulmonary eosinophilia is rare in children and might not be recognized by pediatricians. Diagnosis might be urgent, in the case of dyspnea, hypoxia and/or threatening respiratory signs. The severity of some pulmonary eosinophilias emphasizes the toxicity of the eosinophil granulocyte content. Especially, the major basic protein is capable of destroying the pulmonary epithelium and of facilitating human basophil degranulation. The effect of corticosteroid therapy, spectacular in chronic pulmonary eosinophilia, may be related to their inhibitory effect on eosinophils and by stabilizing cellular membranes.