Objective: Allergic bronchopulmonary aspergillosis
(ABPA) occurs in cases of atopic asthma and may result in
important lung disease. Early diagnosis is essential as this
disease is responsive to steroids. However, while asthma is common,
ABPA is infrequently diagnosed. CT allows precision in the diagnosis of
central bronchiectasis (which is virtually pathognomonic of ABPA) and
may enable earlier diagnosis.
Design: A prospective
evaluation of 255 patients with asthma for ABPA, using skin prick
testing (SPT) for Aspergillus fumigatus (AF) as a
screening tool and incorporating CT into the diagnostic algorithm.
Setting: Asthma clinic, Green Lane Hospital, Auckland, New
Participants: Patients with asthma.
Interventions: ABPA was diagnosed using “essential”
criteria (ie, asthma, SPT positivity to AF, elevated
serum total IgE, elevated serum AF-specific IgE, and pulmonary
infiltrates seen on chest radiography or central bronchiectasis seen on
CT scan) and “minimal essential” criteria (ie,
asthma, SPT positivity, and central bronchiectasis).
Measurements and results: Two hundred fifty-five
consecutive patients with asthma who consented to SPT were studied: 218
of 255 patients (86.8%) were atopic; and 47 of 255 patients (21.6%)
were AF-positive, of whom 35 accepted further evaluation including CT
scanning. A secure diagnosis of ABPA, satisfying all essential
criteria, was evident in 9 of 35 patients (25.7%), a proportion that
increased to 13 of 35 patients (37.1%) by using the minimal essential
Conclusions: SPT positivity to AF
was present in approximately 20% of patients in the asthma clinic. A
diagnosis of ABPA is disclosed by CT in 25 to 40% of SPT-positive
patients, depending on the selection of diagnostic criteria. These
findings support the use of SPT as a screening tool in the asthma
clinic and indicate that a routine CT scan is warranted in SPT-positive