Long-Term Evaluation of Hypersensitivity Pneumonitis: A Case Study Follow-up and Literature Review

This study reports a 3-year follow-up of a classic presentation of hypersensitivity pneumonitis (HP), originally reported elsewhere, after removal of the causative antigens. The literature is reviewed and this case is compared with outcomes of series previously reported. The patient was reevaluated by clinical, serologic, radiographic, and pulmonary function testing 3 years after removal of her home's contaminated humidifier, cleaning of the home, and administration of a course of prednisone. Repeat serologic measurements revealed positive serum precipitins only for Aspergillus flavus and Phoma herbarum, significantly fewer than her original panel, which revealed precipitating antibodies to her humidifier water and 10 other specific antigens. Pulmonary function tests remained stable. Physical exam revealed bibasilar rales. Computed tomography scan revealed pulmonary fibrosis, bronchiectasis, and honeycombing that was compared with 3 years earlier. Although most of the data obtained on reevaluation suggest remission, radiographic findings have not remitted. Long-term follow-up of parameters of HP disease activity do not always reveal consistent findings. This patient appears to be in a category of HP between the classic subacute and chronic stages.