Other nonneoplastic conditions

Acute lung injury

Eosinophilic pneumonia

Last author update: 1 September 2011
Last staff update: 2 May 2022

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PubMed search: Eosinophilic pneumonia lung

Elliot Weisenberg, M.D.
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Cite this page: Weisenberg E. Eosinophilic pneumonia. website. Accessed June 10th, 2023.
Definition / general
  • Acute eosinophilic pneumonia:
    • Diagnosis of exclusion
    • Lung disease associated with eosinophils in alveolar and interstitial spaces, usually with peripheral eosinophilia but excluding Langerhans cell histiocytosis
    • Must exclude drug reactions (antibiotics, cytotoxic or anti-inflammatory drugs), immune disorders (Churg-Strauss syndrome, collagen vascular disease, asthma, hypereosinophilic syndrome, chronic eosinophilic leukemia NOS, myeloid and lymphoid neoplasms with eosinophilia and rheumatoid arthritis), infections (bacteria, Aspergillus, HIV, parasites - helminths, Dirofiliaria and filarial) or tobacco (flavored cigars, new onset of smoking (Chest 2007;131:1234, JAMA 2004;292:2997)
  • Chronic eosinophilic pneumonia:
    • Reaction to drugs, Aspergillus or other fungi, occurs with some malignancies and connective tissue diseases
    • Prolonged (months) febrile illness with cough, weight loss, generalized fatigue, drenching night sweats and peripheral eosinophilia
    • Associated with chronic asthma, usually in setting of allergic bronchopulmonary aspergillosis
    • Xray: patchy infiltrates in peripheral lungs with central sparing
Clinical features
  • Symptoms: fever, weight loss and shortness of breath
  • Xray: peripheral infiltrate
  • Classified as simple, acute or chronic
  • Simple eosinophilic pneumonia (see Loeffler syndrome)
  • Acute eosinophilic pneumonia: onset in 1 - 4 days, accompanied by fever, cough, dyspnea and chest pain; unknown cause, prominent eosinophils in bronchoalveolar lavage fluid and diffuse alveolar damage at biopsy (Am J Respir Crit Care Med 2002;166:1235)
Case reports
  • 6 year old boy post chemotherapy for neuroblastoma with bilateral pulmonary infiltrates (Case #105)
  • Steroids cause dramatic response / complete resolution to acute or chronic forms
Gross description
  • Chronic eosinophilic pneumonia: consolidation, mucus plugs in distal bronchi or bronchioles
Microscopic (histologic) description
  • Acute eosinophilic pneumonia:
    • Acute form has diffuse alveolar damage
    • Alveolar and interstitial infiltration by eosinophils, also plasma cells and histiocytes
    • May have Charcot-Leyden crystals
    • Variable angiitis, granulomatosis, fibrosis, mucus plugging and bronchiolitis with necrosis
  • Chronic eosinophilic pneumonia:
    • Patchy intraalveolar edema, interstitial inflammation with giant cells and eosinophils with scattered histiocytes and plasma cells
    • Mucus plugs composed of inflammatory cells and cellular debris
    • Charcot-Leyden crystals may be present
    • Often bronchiolitis obliterans
    • Blood vessel infiltration by inflammatory cells is common but no vascular necrosis
    • No diffuse alveolar damage
Microscopic (histologic) images

Case #105

Acute eosinophilic pneumonia

Differential diagnosis
Additional references
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