17th February 2025

Aspergillus

Aspergillus moulds, especially Aspergillus fumigatus, can produce a variety of respiratory diseases.

Allergic bronchopulmonary aspergillosis (ABPA)

Asthma precipitated by Aspergillus and ABPA are IgE- and IgG-mediated reactions which are responsive to steroids. Signs and symptoms are typical of asthma and include reduced exercise tolerance and wheeze.

Patients with ABPA have a chronic inflammatory IgE and IgG response to Aspergillus, which causes damage to bronchi and eventually bronchiectasis. Diagnosis is mainly based on a history of asthma (particularly with recurrent exacerbations), IgG precipitins to Aspergillus, central bronchiectasis and a positive skin prick test. Patients benefit from itraconazole alongside steroids and conventional asthma treatment. 

Invasive aspergillosis 

This is when Aspergillus hyphae invade body tissue. Invasive aspergillosis occurs nearly exclusively in cases of immunosuppression. Isolating Aspergillus hyphae from the respiratory tract via sputum or a bronchoalveolar lavage provides a diagnosis.

Invasive disease can cause fever, haemoptysis and dyspnoea when afflicting the lungs; other pathologies, such as endocarditis, depend on the site of dissemination. The lungs are the most common mechanism of entry to the body.

Raised circulating levels of galactomannan, a component of the Aspergillus cell wall, provides evidence of aspergillosis. Management is with a prolonged course of an IV antifungal.

Aspergilloma

Aspergillomas are balls of fungal hyphae that exist within a cavity in the lung, usually secondary to previous tuberculosis infection. Haemoptysis is the most common symptom, but many aspergillomas are asymptomatic. CT thorax may show the halo sign.

Treatment is dependent on symptoms; surgery or antifungals may be required.