Stanford School of Medicine

Surgical Pathology Criteria

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Simple Eosinophilic Pneumonia


  • Transient, minimally symptomatic pulmonary eosinophil infiltrates

Alternate/Historical Names

  • Loeffler syndrome
  • Visceral larva migrans

Covered Separately

Diagnostic Criteria


  • Asymptomatic or minimally symptomatic
  • Generally self-limited


  • Transient pulmonary opacities


  • Hypereosinophilia must be demonstrated in the blood or lung to make the diagnosis
    • Blood eosinophils usually mildly elevated
    • Bronchoalveolar lavage and biopsy rarely performed
  • Generally due to parasitic infection
    • Classically Ascaris larvae migrating through the lung

Gerald J Berry MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting/updates: 11/20/10

Differential Diagnosis

Simple Eosinophilic Pneumonia Acute Eosinophilic Pneumonia Chronic Eosinophilic Pneumonia
Asymptomatic to mild symptoms Fulminant respiratory insufficiency Chronic dyspnea, cough
Blood eosinophils mildly elevated Blood eosinophils normal to mildly elevated Blood eosinophils >1000/mm3
No direct treatment required Steroid responsive, no relapses Steroid responsive, 50% relapse


Known causes of eosinophilic pneumonia must be ruled out

  • Drugs
    • Check history
    • Skin rash suggestive
  • Organisms
    • Check travel history
    • Check stool ova and parasites
    • Check serology for fungi and parasites
    • Culture and stain lavage and biopsy specimens
    • Allergic bronchopulmonary aspergillosis
      • Bronchiolocentric
      • May have necrotizing granulomatous bronchiolitis
      • Mucus plugs common
      • Culture, serology, biopsy identification

Classification / Lists

Idiopathic Interstitial Lung Diseases

Other Diffuse Parenchymal Lung Diseases



  • Travis WD, Colby TV, Koss MN, Rosado-de-Christenson ML, Müller NL, King TE Jr.  Non-neoplastic Disorders of the Lower Respiratory Tract, AFIP Atlas of Nontumor Pathology, First Series, Fascicle 2, 2002.
  • Tazelaar HD, Linz LJ, Colby TV, Myers JL, Limper AH. Acute eosinophilic pneumonia: histopathologic findings in nine patients. Am J Respir Crit Care Med. 1997 Jan;155(1):296-302.
  • Pope-Harman AL, Davis WB, Allen ED, Christoforidis AJ, Allen JN. Acute eosinophilic pneumonia. A summary of 15 cases and review of the literature. Medicine (Baltimore). 1996 Nov;75(6):334-42.
  • Jederlinic PJ, Sicilian L, Gaensler EA. Chronic eosinophilic pneumonia. A report of 19 cases and a review of the literature. Medicine (Baltimore). 1988 May;67(3):154-62.
  • Marchand E, Cordier JF. Idiopathic chronic eosinophilic pneumonia. Orphanet J Rare Dis. 2006 Apr 6;1:11..
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