Introduction: Eosinophilic lung diseases are a diverse group of pulmonary disorders linked by the common finding of increased eosinophilia in blood and/or tissue. They usually present to the clinician as pulmonary infiltrates with eosinophilia for which the differential diagnoses is fairly broad.
Clinical picture: Three patients presented with subacute cough, pulmonary infiltrates and a markedly elevated eosinophil count >1.5 x 109/L. Each case exemplifies its clinical peculiarities and pearls and illustrates the diversity in this group of disorders.
Treatment: A common theme in the approach to its management is excluding infection before proceeding with therapy, often with steroids.
Outcome: There is often a dramatic response to steroid therapy with resolution of symptoms and chest radiographic findings.
Conclusion: The arbitrary label of "pulmonary hypereosinophilia" enables the differential diagnoses to be narrowed to the 4 main categories of infections with parasites or fungus, the Churg-Strauss syndrome, chronic eosinophilic pneumonia and the idiopathic hypereosinophilic syndrome.