Eosinophilic lung disease can occur in idiopathic form or in conjunction with asthma, systemic rheumatoid diseases, parasitic infections or as drug reactions. In these illnesses, abundant eosinophilic leukocytes are accumulated in the airways, the parenchyma and in peripheral blood. Generally speaking, the eosinophilic diseases do not cause fibrosis.
Loeffler’s syndrome (Figure 111) is characterized by migratory opacities with consolidation which may affect all lobes, both centrally and peripherally.
Chronic eosinophilic pneumonia is also characterized by consolidation (Figures 35, 112-113) with subpleural and often apical distribution. The changes may persist for a long period, but generally respond rapidly to cortisone treatment. Approximately half of these patients also have asthma.
Acute eosinophilic pneumonia is a rare acute febrile illness that may lead to respiratory failure. In radiological imaging terms it is described as edema-like. Cortisone treatment is very effective.
Hypereosinophilic syndrome is a rare multiorgan disease. Eosinophilic infiltrates can be found in the heart, lungs and other internal organs. The HRCT pattern varies from nodules to consolidation.
Churg-Strauss syndrome (Figure 114) is a small vessel vasculitis occurring in patients with asthma. The patients have eosinophilia, and lung changes are seen in approximately half of cases. The HRCT pattern varies and includes patchy ground-glass, crazy paving, elements of consolidation and sometimes nodules. The picture is very unspecific, and consequently diagnosis is based on a typical triad of small vessel vasculitis, asthma and eosinophilia.