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Farmer's Lung Follow-up

  • Author: Laurianne G Wild, MD, FAAAAI, FACAAI; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
Updated: Dec 21, 2015

Further Outpatient Care

Outpatient care includes the following:

  • Routine spirometry with lung volumes and diffusion capacity.
  • Arterial PO2 and arterial-alveolar gradient: Recommend exercise (6-min walk or by ergometer) if the room air PO2 level is normal.
  • Monitor chest radiographs and consider high-resolution CT scans of the chest to seek resolution of infiltrates or presence of ground-glass opacities that may indicate a need for further treatment with corticosteroids and/or continued insult to the lungs by antigen exposure.

Further Inpatient Care

Inpatient care includes the following:

  • Systemic corticosteroids
  • Serum precipitins
  • Flexible bronchoscopy to exclude other etiologies
  • Transbronchial biopsy may be of limited benefit in patients with acute farmer's lung.
  • Open lung biopsy may be indicated to confirm the diagnosis if other diagnostic criteria are not met


Complete avoidance of the antigen is indicated. Consider the following:

  • Protective devices (eg, masks) may reduce the amount of antigen; however, again, complete avoidance is recommended.
  • Maintaining humidity at less than 60% may discourage microbial growth.
  • Keeping hay on farms dry and well protected may discourage growth of bacteria and molds. However, salting of hay, a traditional empirical practice used to prevent molding in hay, does not significantly decrease the amount of actinomycetes, the organisms most commonly involved in farmer's lung disease. Salting of hay may provide a false sense of security that the farmer is protected from developing farmer's lung; this false notion should be dispelled.[18]


Complications of farmer's lung include the following:

  • Cor pulmonale
  • Hypoxemic respiratory failure
  • Pulmonary fibrosis
  • Death


The long-term prognosis of farmer's lung varies and depends on the extent of fibrosis and the amount of irreversible damage to the lung parenchyma.[19]  Consider the following:

  • In some patients, the disease may progress even after the antigen exposure has been eliminated.
  • If the diagnosis of farmer's lung is confirmed before irreversible changes have developed, most patients recover with minimal functional abnormalities and few become disabled.
  • In the acute stages, restriction with decreased static compliance and diffusing capacity that reverses over several weeks (with antigen avoidance) may occur.
  • In subacute disease, bronchiolitis and granuloma formation might be slower to resolve even with corticosteroid therapy.
  • Individuals with a ground-glass appearance on high-resolution CT scans of the chest have higher response rates to systemic corticosteroids.
  • Patients with honeycombing or pulmonary fibrosis may have less than a 20% response to corticosteroids and a mortality rate greater than 90% at 5 years after diagnosis.
  • Predictors of long-term decline in farmer's lung include recurrent acute episodes, allergy to mites, organic dust, and fungal elements, and smoking, which promotes deterioration of lung function in patients diagnosed with farmer's lung.[20]

Patient Education

Environmental control and complete avoidance of the antigen should be the goal. Complete avoidance of the environment or farm may be required to ensure prevention of chronic disease and survival.

Many farmers have thought that salting the hay can prevent the growth of molds in the hay. However, salting does not prevent the growth of molds. The use of salt does not significantly decrease the amount of Saccharopolyspora rectivirgula (the actinomycetes most commonly involved in farmer's lung disease), or Absidia corymbifera, Eurotium amstelodami, and Wallemia sebi, 3 molds responsible for farmer's lung disease in Europe. Therefore, palatable hay is not safe hay.

For patient education information, see Bronchoscopy.

Contributor Information and Disclosures

Laurianne G Wild, MD, FAAAAI, FACAAI Chief and Professor of Clinical Medicine, Section of Clinical Immunology, Allergy and Rheumatology, Director, Allergy and Immunology Fellowship Training Program, Tulane University School of Medicine; Director, Allergy and Immunology Clinic, Southeast Louisiana Veterans Health Care System of New Orleans

Laurianne G Wild, MD, FAAAAI, FACAAI is a member of the following medical societies: Alpha Omega Alpha, American Academy of Allergy Asthma and Immunology, American College of Allergy, Asthma and Immunology, Association of Subspecialty Professors

Disclosure: Nothing to disclose.


Eduardo E Chang, MD Fellow, Department of Allergy and Immunology, Tulane University

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Zab Mosenifar, MD, FACP, FCCP Geri and Richard Brawerman Chair in Pulmonary and Critical Care Medicine, Professor and Executive Vice Chairman, Department of Medicine, Medical Director, Women's Guild Lung Institute, Cedars Sinai Medical Center, University of California, Los Angeles, David Geffen School of Medicine

Zab Mosenifar, MD, FACP, FCCP is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, American Federation for Medical Research, American Thoracic Society

Disclosure: Nothing to disclose.

Additional Contributors

Sat Sharma, MD, FRCPC Professor and Head, Division of Pulmonary Medicine, Department of Internal Medicine, University of Manitoba; Site Director, Respiratory Medicine, St Boniface General Hospital

Sat Sharma, MD, FRCPC is a member of the following medical societies: American Academy of Sleep Medicine, American College of Chest Physicians, American College of Physicians-American Society of Internal Medicine, American Thoracic Society, Canadian Medical Association, Royal College of Physicians and Surgeons of Canada, Royal Society of Medicine, Society of Critical Care Medicine, World Medical Association

Disclosure: Nothing to disclose.


Gregg T Anders, DO Medical Director, Great Plains Regional Medical Command , Brooke Army Medical Center; Clinical Associate Professor, Department of Internal Medicine, Division of Pulmonary Disease, University of Texas Health Science Center at San Antonio

Disclosure: Nothing to disclose.

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