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Loffler Syndrome


General Considerations

  • An acute respiratory illness with peripheral blood eosinophilia, one of the causes of pulmonary infiltrates with eosinophilia (PIE)
  • Originally described as a reaction to the pulmonary phase of Ascaris lumbricoides
  • Also caused by drugs induced pulmonary eosinophilia
  • Some of the drugs associated are
    • Antimicrobials such as penicillin, tetracycline INH and nitrofurantoin
    • Anticonvulsants such as Dilantin and valproic acid
    • Anti-inflammatory agents such as aspirin, naproxen and ibuprofen
    • Bleomycin, chlorpromazine, imipramine, sulfonamides

Other Causes of Pulmonary Infiltrates with Eosinophilia


Acute Eosinophilic Pneumonia

Chronic Eosinophilic Pneumonia

Hypereosinophilic Syndrome

Associated with Diffuse Lung Diseases

E.g. Lupus

Secondary to Infection

Allergic Bronchopulmonary Aspergillosis


Clinical Findings

  • Dry cough is most common
  • Fever, malaise
  • Dyspnea
  • Myalgia

Imaging Findings

  • Unilateral or bilateral air space densities, usually peripherally located (reverse pulmonary edema)
  • Transient, disappearing in 2-4 weeks
  • Rarely pleural effusion, especially with nitrofurantoin toxicity

Differential Diagnosis

  • Asthma
  • See table above


  • Benign, self-limiting disease
  • Symptoms usually subside in 3-4 weeks

 Loffler (Loeffler) Syndrome 
Loffler (Loeffler) Syndrome. There are bilateral peripheral infiltrates in the upper lung fields. This has been called the reverse pulmonary edema sign.


loeffler syndrome

Loffler (Loeffler) Syndrome. Chest radiograph on another patient shows peripheral , primarily upper lobe airspace disease.

Eosinophilic lung diseases: a clinical, radiologic, and pathologic overview. YJ Jeong,  KI Kim, IJ Seo, et al. Radiographics. 27 (3): 617-37