Hypersensitivity pneumonitis

Table 6 Distribution of diagnoses in the HP Study [4]

Diagnosis	Number of patients
Hypersensitivity pneumonitis	199
Pigeon breeder's/bird fancier's disease	132
Farmer's lung	38
Humidifier lung	3
Suberosis	2
Summer type HP	2
Various exposures to fungi	19
HP of unknown origin	3
Controls	462
Idiopathic interstitial pneumonia *	226
Sarcoidosis	52
Interstitial disease associated with collagen vascular disease	35
Drug induced pulmonary disease	26
Bronchiolitis obliterans (with our without organizing pneumonia)	25
Unspecified interstitial lung disease †	26
Infectious pneumonia	11
Histiocytosis X	10
Asthma	6
Silicosis	5
Eosinophilic pneumonia	5
Normal lung	4
Bronchoalveolar carcinoma/carcinomatous lymphangitis	4
Residual HP ‡	3
Residual HP ‡	3
Organic dust toxic syndrome	3
Lymphocytic interstitial pneumonia	2
Pulmonary edema (heart failure)	2
Radiation pneumonitis	2
Miscellaneous §	13
TOTAL	661

* includes patients with the clinical diagnosis of idiopathic pulmonary fibrosis, and those with the pathological diagnoses of usual, desquamative, respiratory bronchiolitis, acute and non-specific interstitial pneumonia;
† includes patients in whom no specific diagnosis could be reached but in whom HP was excluded on the basis of BAL;
‡ includes late emphysematous or fibrotic sequelae of HP in which the typical alveolar lymphocytosis of active HP has disappeared;
§includes single cases of alveolar hemorrhage, anthracosis, berylliosis, Churg-Strauss syndrome, diffuse panbronchiolitis, hepato-pulmonary syndrome, HIV-associated nonspecific interstitial pneumonia, necrotizing sarcoid granulomatosis, pulmonary amyloidosis, alveolar proteinosis, crack lung, Pneumocystis carinii pneumonia, and Wegener's granulomatosis.

ISSN: 1750-1172