Guidelines for managing allergic bronchopulmonary aspergillosis (ABPA) have been overhauled in response to nearly a decade of new evidence and advances in diagnosing and treating the condition.
“These guidelines will help bring uniformity in diagnosis and simplify the management of ABPA patients in clinical care and research,” said the international expert task force that included Professor Jo Douglass, an allergy specialist at the University of Melbourne and Royal Melbourne Hospital.
In the guidance published in the European Respiratory Journal (link here), the task force has recommended that all newly diagnosed adult asthmatics in tertiary care are screened specifically for A. fumigatus sensitisation (rather than all fungi), using fungus-specific IgE (in preference to a skin prick test).
While the majority of patients with ABPA have moderate-to-severe asthma, some have mild forms of the disease, and so screening solely based on symptoms or asthma control risks missing several cases, they warned.
“Screening is essential since ABPA can occur even in mild asthmatics, and there is a high risk of progression to bronchiectasis if ABPA is undetected,” the group stressed.
“Other fungi (other Aspergillus spp., Candida, Penicillium, Alternaria, Cladosporium, and Trichophyton) are also implicated in allergic sensitisation; however, they rarely cause allergic airway mycoses.
“Thus, evaluation for sensitisation to other fungi may be reserved in difficult-to-treat asthma patients who do not have A. fumigatus sensitisation,” they noted.
Among children, only those with difficult-to-treat asthma should undergo A. fumigatus sensitisation screening, the experts agreed.
To exclude ABPA in patients with confirmed A. fumigatus sensitisation, the following immunological tests and cut-off levels should now be used to ensure best practice: A. fumigatus-specific IgE (≥0.35 kUA/L) and -IgG, serum total IgE (≥500 IU/mL), and peripheral blood eosinophil count (≥500 cells/µL).
In addition, a thin-section chest CT consistent with ABPA (bronchiectasis, mucus plugging, and high-attenuation mucus) or fleeting opacities on a chest radiograph consistent with the condition can be used to diagnose the condition.
The group also newly developed separate diagnostic criteria for diagnosing allergic bronchopulmonary mycosis (ABPM), i.e. patients with ABPA-like presentation but normal A. fumigatus IgE.
Elevated fungus-specific IgE and a serum total IgE of ≥500 IU/mL were deemed essential components for diagnosing ABPM, in addition to two of the following: positive fungus-specific IgG; blood eosinophil count ≥500 cells/µL; two sputum fungal cultures growing the causative fungus; and radiographic features consistent with ABPA.
Revised classification and treatment
The task force also revised recommendations for the clinical classification of ABPA(M) to address previous shortcomings.
Crucially, the prior numbered stages have been removed to avoid the misconception that patients might progress sequentially from one to the other.
Five categories were retained (acute ABPA, response, remission, treatment-dependent ABPA, and advanced ABPA), but the asymptomatic stage and glucocorticoid-dependent asthma were removed “as they had no clear treatment implications in ABPA”, it was noted.
With regard to treatment, it was stressed that acute cases of ABPA require systematic therapies.
The group agreed on initial therapy of a low-to-moderate dose (0.5 mg/kg/day for 2-4 weeks, tapered and completed over four months) of oral prednisolone or oral itraconazole.
“We do not recommend using a combination of itraconazole and glucocorticoids as first-line therapy for acute ABPA. However, a short course of glucocorticoids (<2 weeks) may be used as initial therapy along with oral itraconazole,” they said.
There was also a high level of agreement that high-dose ICS (100%) or biologics (97%) “should not be used as primary therapy for acute ABPA”, according to the paper.
Other key recommendations included monitoring patients for treatment response for 8-12 weeks using clinical symptoms, serum total IgE, and chest radiographs and treating ABPA exacerbations post-treatment ” in the same manner as newly diagnosed ABPA.”
See the new guidelines in full here