Background Severe Asthma with Fungal Sensitisation (SAFS) is a newly described phenotype of Fungal Allergic Asthma. There is much debate about the disease’s mechanism of action, the best method of treatment and how treatment with antifungal agents such as Itraconazole brings about the improvement in disease control that has been shown in previous studies.

This study aims to answer those questions, through the use of Sputum Aspergillus Polymerase Chain Reaction testing as a method of determining whether a patient has pulmonary colonisation with Aspergillus.

Methods PCR samples were collected between September 2012 and May 2013 samples taken clinically in the previous 2 years were also included. Patients had their antifungal therapy status recorded and received Total serum IgE and Aspergillus Specific IgE testing when providing sputum samples. The study was split into 2 arms. The primary retrospective opportunistic arm had a patient cohort of 135 who provided 254 samples for testing and analysis. The secondary prospective arm of the study looked at 10 patient’s commencing Itraconazole therapy. Patients received PCR testing before commencing treatment and then at every opportunity whilst on treatment.

The primary study arm showed a 70% rate of pulmonary colonisation in the Untreated Severe Asthma population, which differs significantly to the 9% rate of positivity seen in the control population. The rate of PCR positivity fell to 23% in the SAFS population who were receiving treatment. The secondary arm showed that Itraconazole removed fungus from the airways of 9 patients; this was correlated with a decrease in patient’s total serum IgE’s.

Discussion The 70% rate of PCR positivity in the untreated SAFS population supports the concept that patients with SAFS have pulmonary colonisation with Aspergillus. The study has also shown that the antifungal agent Itraconazole removes this fungus from patient’s airways and that is correlated with an improvement in patient’s disease control. This study supports the use of Itraconazole in patients with SAFS.