Abstract
Hypersensitivity pneumonitis is a group of inflammatory interstitial lung diseases caused by hypersensitivity immune reactions to the inhalation of various antigens: fungal, bacterial, animal protein, or chemical sources, finely dispersed, with aerodynamic diameter <5μ, representing the respirable fraction. The national register for interstitial lung diseases records very few cases of hypersensitivity pneumonitis (extrinsec allergic alveolitis), a well defined occupational disease. Although not an eminently of occupational origin, the extrinsec allergic alveolitis can occur secondary to occupational exposure to organic substances (animal or insect proteins, bacteria, fungi) or inorganic (low molecular weight chemical compounds) and the occupational doctor is a key actor in the diagnosys. The disease has chronic evolution and exposure avoidance, as early as possible, has major prognostic influence. The occupational anamnesis remains the most important step and the occupational physician is the one in charge for monitoring and detection of the presence of respiratory symptoms in all employees with risk exposure. Next, we present the case of a farmer, without other comorbidities, who develops various respiratory and systemic diseases and manifestations due to repeated exposure to animal proteins and molds, in order to review the risk factors and the consequences of exposure in poultry farms.