Alveolitis, Extrinsic Allergic

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Alveolitis, Extrinsic Allergic is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Extrinsic allergic alveolitis is a lung disorder resulting from repeated inhalation of organic dust, usually in a specific occupational setting. In the acute form, respiratory symptoms and fever begin several hours after exposure to the dust. The chronic form is characterized by gradual changes in the lung tissue associated with several years of exposure to the irritant.


In general, symptoms of all forms of Extrinsic Allergic Alveolitis include breathing difficulty, wheezing, and dry coughs that appear to shake the entire body. Chills, sweating, aching, discomfort and/or fatigue may accompany lung symptoms. Most cases of this disorder are characterized by mild, short episodes that may be misdiagnosed. Chronic cases may develop with repeated episodes or prolonged exposure to a specific organic dust. These may involve more severe symptoms including fever, crackling sounds during breathing (rales), breathing difficulty, bluish appearance of the skin (cyanosis), and possibly, expectoration of blood 3.


Extrinsic allergic alveolitis is caused by repeated exposure to animal or vegetable dusts, usually but not exclusively, in occupational settings. In order to get into the lung's tiny sacs where the oxygen is exchanged with the blood, these dusts must be less than a certain size, described as 5 microns. (A micron is one-millionth of a meter in size, and thus about one twenty-five thousandth of an inch.)

A wide variety of substances encountered in occupational settings may be linked to this disorder, including irritants associated with birds (avian dust), cheese manufacturing (mold), sugar manufacturing (moldy sugar cane dust), bath tub refinishing (paint catalyst), farming (moldy hay dust), mushroom farming (mushroom compost), working in a laboratory (rat or gerbil urine residue), tobacco (snuff), heating and cooling systems (moldy water), malt working/beer brewing (moldy barley), maple bark disease (moldy maple bark dust), sequoiosis (moldy redwood bark dust), suberosis (moldy cork dust), plastic working (plastic residue), epoxy resin (heated epoxy residue), enzyme detergent (dust), or wheat weevil disease (wheat mold or dust).

Affected Populations

Extrinsic allergic alveolitis may affect males and females in equal numbers, but usually affects individuals in occupations in which animal or vegetable dusts are inhaled by people allergic to the substances contained in such dusts.

Standard Therapies

Treatment of extrinsic allergic alveolitis initially depends on identification of the cause of the allergic reaction. If possible, the patient should avoid exposure to the allergen. In an occupational setting, mild cases may be alleviated by improved ventilation or use of air filtering masks. In severe or prolonged cases, however, changing jobs may be the better option. If symptoms persist in spite of avoidance, corticosteroid drugs may be tried. In acute cases, steroids in combination with avoidance measures can often reduce the severity of symptoms. All symptoms can usually be resolved in acute cases if they are diagnosed and treated early before permanent changes in the lungs can develop. If permanent lung changes have occurred at the time of diagnosis, it is possible that the patient may not respond well to treatment.

Investigational Therapies

Information on current clinical trials is posted on the Internet at All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.

For information about clinical trials being conducted at the National Institutes of Health (NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:

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For information about clinical trials sponsored by private sources, contact:



Moore JE, Convery RP, Millar BC, et al. Hypersensitivity pneumonitis associated with mushroom worker's lung: an update on the clinical significance of the importation of exotic mushroom varieties. Int Arch Allergy Immunol. 2005;136:98-102.

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Miranowski AC, Grammer LC. Occupational immunologic lung disease. Allergy Asthma Proc. 2004;25(4 suppl 1)S36-37.

Greenberger PA. Mold-induced hypersensitivity pneumonitis. Allergy Asthma Proc. 2004;25:219-23.

Selman M. Hypersensitivity pneumonitis: a multi-faceted deceiving disorder. Clin Chest Med. 2004;25531-47.

Mohr LC. Hypersensitivity pneumonitis. Curr Opin Pulm Med. 2004;10:401-11.

Agostini C, Trentin L, Facco M, et al. New aspects of hypersensitivity pneumonitis. Curr Opin Pulm Med. 2004;10:378-82.


Khan AN, Irion KL, Kasthuri RS, et al. Extrinsic Allergic Alveolitis. emedicine. Last Updated: February 22, 2005. 19pp.

Sharma S. Hypersensitivity Pneumonitis. emedicine. Last Updated: March 8, 2005. 14pp.

Supporting Organizations

American Academy of Allergy, Asthma and Immunology

611 East Wells Street
Milwaukee, WI 53202
Tel: (414)272-6071
Fax: (414)276-3349
Tel: (800)822-2762
Website: //

American Lung Association

55 W. Wacker Drive
Suite 1150
Chicago, IL 60601
Tel: 1-800-548-8252
Website: //

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
Website: //

NIH/National Institute of Allergy and Infectious Diseases

NIAID Office of Communications and Government Relations
5601 Fishers Lane, MSC 9806
Bethesda, MD 20892-9806
Tel: (301)496-5717
Fax: (301)402-3573
Tel: (866)284-4107
Website: //

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see