The Association of Asthma with Aspergillus and Other Fungi

Summary: Five indices of allergic asper‐gillosis (radiographic abnormality, including upper lobe contraction, irregularity of bronchial walls and transient pulmonary infiltration, serial monthly sputum culture, immediate skin reaction, serum precipitins and bronchial reaction to inhalation) were studied in 38 asthmatic subjects drawn from approximately 250 patients admitted to a thoracic unit. Twenty‐three of the patients were selected because of radiographic abnormality or previous positive sputum cultures, neither of these features being present in the remainder. Serum precipitins, but not skin or bronchial reactivity, were significantly more frequent in the selected subjects. Subdivision of the entire series on the basis of radiographic abnormality or of skin sensitivity revealed a trend towards an association between the five indices, but in no case were all five indices present. Three or four indices were present in eleven of the 38 patients. If all five are required to establish the diagnosis, allergic aspergillosis must be rare in Sydney, but spontaneous fluctuations in natural history and problems of methodology conspire to reduce the likelihood of finding all five indices positive, particularly at any one point in time. The clinical course of three patients is cited to support an association between asthma and aspergillus sensitivity when fewer than five indices of allergic aspergillosis were identified. Aspergillus, isolated from the sputum of 20 patients, was rarely isolated in monthly cultures from the patients' homes, whereas alternaria and penicillium , rarely isolated from the sputum, were found in all homes. Skin sensitization rates to these moulds, and also to mucor (occasionally isolated from the sputum but never from the home) were comparable (approximately 40–67%). Although other interpretations are possible, these observations suggest that the capacity of aspergillus to produce sensitization is related to its ability to colonise the bronchial tree more than to chance environmental contact; environmental contact may be the major factor in determining skin sensitivity to other fungi.