Some authors are now reporting that there are only two clinical syndromes; however, they vary as to whether they group sub-acute with the acute or the chronic form. Many cases of HP are caused by occupational exposure.
The clinical manifestations of HP depend on the concentration and frequency of exposure. The clinical syndromes - acute, sub-acute, and chronic HP - present differently.
The inflammation of HP manifests itself in the alveoli and distal bronchioles.
HP is caused by repeated inhalation of non-human protein, which can be of natural plant or animal origin or can be the result of a chemical conjugated to a human airway protein, such as albumin.
also known as extrinsic allergic alveolitis, is the result of non-IgE mediated immunological inflammation
