Hypersensitivity pneumonitis overview

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Overview
Hypersensitivity pneumonitis (HP), also called extrinsic allergic alveolitis (EAA), is not a single disease but is a complex syndrome of varying intensity, clinical presentation, and natural history.

The syndrome was first described in Iceland in 1874 and termed heykatarr. The syndrome is caused by sensitization to repeated inhalation of dusts containing one of 300 organic antigens. These organic dusts come from a wide variety of sources but most commonly include:


 * Dairy and grain products
 * Animal dander and protein
 * Wood bark
 * Water reservoir vaporizers

The two most common antigens are:
 * 1) Thermophilic actinomycetes and
 * 2) Avian proteins

As a rseult of exposure to thee antigens, the two most common causes (i.e. diseases) are:
 * 1) Farmer's lung and
 * 2) Bird fancier's lung

Pathologically, the HP syndrome is associated with diffuse inflammation of lung parenchyma and airways.

Based on the length and intensity of exposure and subsequent duration of illness, there are 3 clinical presentations of HP:


 * 1) Acute
 * 2) Subacute (intermittent)
 * 3) Chronic progressive

Synonyms and related keywords: hypersensitivity pneumonitis, HP, bird fancier's lung, extrinsic allergic alveolitis, farmer's lung, Saccharopolyspora rectivirgula, S rectivirgula, Micropolyspora faeni, M faeni, Thermoactinomyces sacchari, T sacchari, Thermoactinomyces vulgaris, T vulgaris, Penicillium casei, P casei, Aspergillus clavatus, A clavatus, Mucor stolonifer, M stolonifer, Sitophilus granarius, S granarius, Cladosporium, heykatarr, bagassosis, grain handler's lung, humidifier lung, air-conditioner lung, bird breeder's lung, cheese worker's lung, malt worker's lung,paprika splitter's lung, mollusk shell hypersensitivity, chemical worker's lung, pulmonary disease, lung disease.