Cryptogenic pulmonary eosinophilias.

Abstract

SummaryIn the U.K. allergic bronchopulmonary aspergillosis is the cause of pulmonary eosinophilia (PE) in about 80% of the instances. The purpose of this paper is to describe distinctive clinical, immunological, radiological and respiratory functional changes in twenty‐seven cases of PE in whom an aetiological diagnosis was not possible (cryptogenic pulmonary eosinophilia) and contrast the findings with those of allergic bronchopulmonary aspergillosis. In the cryptogenic pulmonary eosinophilias the degree of eosinophilia of blood and sputum was more marked than in allergic bronchopulmonary aspergillosis, females were more frequently affected and there was no seasonal predilection. Cough and sputum was not prominent, plugs were rarely seen in the sputum, A. fumigatus was rarely cultured, and secondary bacterial infection was uncommon. Corticosteroids were effective in treating both varieties of PE. In contrast to bronchopulmonary aspergillosis where Type I and Type III immunological responses were elicited following skin, inhalation and serological tests, immunological mechanisms could not be demonstrated in cryptogenic PE. Radiologically, diffuse often bilateral low density and peripheral shadowing were typical in the latter while recurrent perihilar shadows, bronchiectasis, lobar shrinkage, and atalectasis were encountered in allergic bronchopulmonary aspergillosis. Functionally, the severity of airway obstruction and defect in carbon monoxide transfer tended to be less severe than in allergic bronchopulmonary aspergillosis. Finally systemic periarteritis nodosa developed in two patients with cryptogenic pulmonary eosinophilia but was not encountered in allergic bronchopulmonary aspergillosis.