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).
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.
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.
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