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Löffler's disease, or simple pulmonary eosinophilia, was first described in 1932.[1] It is defined as transient respiratory illness associated with eosinophilia and chest X-ray abnormalities. In 1952, it was classified as one of the five causes of pulmonary infiltrates with eosinophilia.[2] The pathology is essentially allergic. It may arise from infestation (most commonly with Ascaris lumbricoides) or from exposure to certain drugs.

In about a third of cases, no cause is identified. Recognised causes include:

Ascaris lumbricoides has a life cycle that includes lodging in the pulmonary capillaries, migrating through the alveolar wall and progressing up the bronchial tree, ultimately to be swallowed. However, this is not essential to produce the pathology as the condition may arise from parasites that do not have this pulmonary component to their life cycle.

This is an uncommon condition in the UK but is more likely in children and more likely in parts of the world where parasitic infestation abounds.


Symptoms are usually mild or absent and tend to resolve spontaneously after several days or, at most, after two or three weeks:

  • Cough - usually dry and unproductive
  • Small amounts of mucoid sputum

With infestation-related illness, symptoms may also occur including:

  • Fever
  • Malaise
  • Wheezing and dyspnoea
  • Less commonly, myalgia, anorexia, and urticaria

In Ascaris infestation, symptoms occur 10-16 days after ingestion of the eggs but the actual time of ingestion is frequently unknown and the duration will vary with the life cycle of the species involved. Ask specifically regarding travel history as this may determine exposure to different parasites.

With drug-induced disease, symptoms may start hours after taking the medications but, more usually, it does not present for several days. Dry cough, breathlessness, and fever are common. Obtain a detailed drug history.

Always ask specifically about over-the-counter drugs, illicit drugs, alternative medicines and dietary supplements, as the patient may be ingesting something with pharmacological properties that they do not volunteer as part of a 'medical' history.


Often there is no physical abnormality to be found. Occasionally, examination of the lungs may reveal crackles or wheezes on auscultation. This is more common with drug-induced pulmonary eosinophilia than with infestation.

  • Blood tests: FBC will show eosinophilia, often between 5-20% but may be up to 40% with drug-induced disease.
  • Radiology:
    • Plain CXR is usually adequate and scanning is not required, although CT scan may be helpful at times in differential diagnosis of the type of eosinophilic lung disease.[5]
    • Typically, there are transient and migratory patches of consolidation which clear spontaneously within one month. Abnormalities can be unilateral or bilateral.
    • Consolidations are nonsegmental, single or multiple, with ill-defined margins and usually have a predominantly peripheral distribution. Densities are usually a few centimeters in diameter, although they may coalesce into larger areas of consolidation.
    • In drug-induced disease it may take several weeks after the withdrawal of the offending drug for the CXR to return fully to normal.
    • In patients with nitrofurantoin toxicity there may even be pleural effusion.
    • High-resolution CT findings show ground-glass opacity or airspace consolidation involving mainly the peripheral regions of the middle and upper lung zones.[6]
  • Microbiology: parasites may be found in the stool for 6-12 weeks after the initial infection but this will depend upon the nature of the infection.
  • Pathology: specimens will show oedema and accumulation of eosinophils in the alveolar septa and interstitium.[6] Parasitic forms are not usually found in the lungs.
  • It is first necessary to identify a cause wherever possible: where a drug is implicated, then it should be withdrawn or, where an infestation is diagnosed, the parasite should be eradicated.
  • Specific symptomatic treatment may be unnecessary if symptoms are trivial. Otherwise, steroids are used to control symptoms. They are very effective at reversing the eosinophilia but it is important to treat the patient and not to treat a laboratory result. The dose and duration of steroid will depend upon relief of symptoms.
  • Between 4 and 6 weeks after presentation, repeat FBC and CXR to ascertain resolution. Also repeat stool samples to check complete eradication.

Löffler's disease tends to follow an uncomplicated course and resolve completely within a month. Recurrence occurs only if infection recurs or the offending drug is reintroduced.

This is largely the prevention of parasitic infestation in endemic areas. Good hygiene and hand washing before eating are also important.

Wilhelm Löffler was born in 1887 and died in 1972. He studied in Geneva, Vienna, Strasbourg, and Basel, where he obtained his doctorate in 1911. In 1921 he became Extraordinary Professor of Medicine and Director of the University Medical Polyclinic at the University of Zurich. He introduced the mass X-ray service to screen for tuberculosis in Switzerland. He was one of the first to use insulin. He first described diffuse mural endocarditis called endocarditis parietalis fibroplastica with eosinophilia, giving congestive cardiac failure. This is called Löffler's endocarditis. A mild form of pulmonary infiltration with eosinophilia, and differing from Löffler's disease by its chronic course, is called Kartegener's disease.

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Further reading and references

  1. Loffler W. Zur Differential-Diagnose der Lungenifiltrierungen. II. Über flüchtige Succedan-Infiltrate (mit Eosinophilie). Beitrage zum Klinik der Tuberkulose, 1932, 79, 368-382.

  2. Crofton JW, Livingstone JL, Oswald NC, et al; Pulmonary eosinophilia. Thorax. 1952 Mar

  3. Talmacui I; Loffler syndrome eMedicine April 2006.

  4. Nadeem S, Nasir N, Israel RH; Loffler's syndrome secondary to crack cocaine. Chest. 1994 May

  5. Kim Y, Lee KS, Choi DC, et al; The spectrum of eosinophilic lung disease: radiologic findings. J Comput Assist Tomogr. 1997 Nov-Dec

  6. Jeong YJ, Kim KI, Seo IJ, et al; Eosinophilic lung diseases: a clinical, radiologic, and pathologic overview. Radiographics. 2007 May-Jun27(3):617-37