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Löffler's disease

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find one of our health articles more useful.

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What is Löffler's disease?1

Löffler's disease is a transient form of self-limited, benign pulmonary eosinophilia with absent or mild respiratory symptoms (particularly dry cough), fleeting migratory pulmonary opacities, and peripheral blood eosinophilia. The disease usually lasts less than a month.

Loffler's disease was firstly defined by Wilhelm Loffler in 1932 as a clinical disorder characterised by transient respiratory illness associated with blood eosinophilia and radiographic shadowing.

Many lung diseases have migratory pulmonary infiltrates, and the term Loffler's disease is interchangeably used with a variety of other names, including simple pulmonary eosinophilia, cryptogenic eosinophilic pneumonia, larval pneumonitis, pulmonary infiltrates with eosinophilia, and Loffler's pneumonia.

The pathology is essentially allergic and it may arise from infestation (most commonly with Ascaris lumbricoides) or from exposure to certain drugs.

Eosinophilic pneumonia2

Eosinophilic pneumonia, also known as pulmonary infiltrates with eosinophilia, is a rare and heterogeneous syndrome that is classified according to chronicity and aetiology.

There are 2 major types of eosinophilic pneumonia:3

  • Acute eosinophilic pneumonia.

  • Chronic eosinophilic pneumonia.

There is some overlap in the characteristics of these 2 syndromes, including eosinophilic infiltration of the pulmonary parenchyma and clinical symptoms such as dry cough, dyspnoea, chest pain, and fever. Although both respond well to corticosteroids, relapse frequently occurs in patients with chronic eosinophilic pneumonia, but rarely in those with acute eosinophilic pneumonia. Acute eosinophilic pneumonia is characterised by symptoms lasting less than 1 month and usually less than 1 week.

Löffler's disease aetiology4

In about a third of cases, no cause is identified.

The causes of pulmonary infiltrates with eosinophilia associated with infection or drugs include:

  • Allergic bronchopulmonary aspergillosis.

  • Infectious causes of pulmonary eosinophilia:

    • Helminthic infections: strongyloidiasis, schistosomiasis, fascioliasis, opisthorchiasis, clonorchiasis, gnathostomiasis, paragonimiasis, echinococcosis, coccidioidomycosis, toxocariasis.

    • Non-helminthic infections: ectoparasites, fungal infections, mycobacterial infections, HIV.

  • Drug-induced pulmonary eosinophilic syndromes: anticonvulsants, sulfonamides, allopurinol, vancomycin, minocycline.

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Löffler's disease epidemiology

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.

Löffler's disease symptoms (presentation)3


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.

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.

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  • 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 centimetres 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.

Differential diagnosis3

Other causes of pulmonary infiltrates with eosinophilia associated include:

Löffler's disease treatment and management4

True Löffler's disease is usually mild and transient, only requiring treatment of any underlying cause.

For eosinophilic pneumonia, high dose steroids and management of hypoxaemia and respiratory failure as required. Optimal management is otherwise directed at the underlying cause when identifiable, and the urgency of management guided by the presence or absence of end-organ manifestations.4


True Löffler's disease, as a transient cause of pulmonary infiltrates with eosinophilia, will usually resolve within one month.

The prognosis of pulmonary eosinophilia will depend on the underlying cause.

Although chronic eosinophilic pneumonia occasionally persists and becomes corticosteroid dependent, most patients with acute eosinophilic pneumonia completely recover.3


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

Further reading and references

  1. Tran KH, Nguyen-Thi KH, Pham NC, et al; Loeffler's syndrome in a child: A rare radiological and histopathological diagnosis. Radiol Case Rep. 2021 Nov 18;17(1):245-249. doi: 10.1016/j.radcr.2021.10.044. eCollection 2022 Jan.
  2. Bartal C, Sagy I, Barski L; Drug-induced eosinophilic pneumonia: A review of 196 case reports. Medicine (Baltimore). 2018 Jan;97(4):e9688. doi: 10.1097/MD.0000000000009688.
  3. Suzuki Y, Suda T; Eosinophilic pneumonia: A review of the previous literature, causes, diagnosis, and management. Allergol Int. 2019 Oct;68(4):413-419. doi: 10.1016/j.alit.2019.05.006. Epub 2019 Jun 25.
  4. Rosenberg CE, Khoury P; Approach to Eosinophilia Presenting With Pulmonary Symptoms. Chest. 2021 Feb;159(2):507-516. doi: 10.1016/j.chest.2020.09.247. Epub 2020 Sep 28.
  5. Kim Y, Lee KS, Choi DC, et al; The spectrum of eosinophilic lung disease: radiologic findings.; J Comput Assist Tomogr. 1997 Nov-Dec;21(6):920-30.
  6. Jeong YJ, Kim KI, Seo IJ, et al; Eosinophilic lung diseases: a clinical, radiologic, and pathologic overview. Radiographics. 2007 May-Jun;27(3):617-37; discussion 637-9.

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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