Aspergillose

Aspergillosis is a group of diseases caused by fungi of the genus Aspergillus, most commonly Aspergillus fumigatus. It results from inhalation of airborne spores and ranges from allergic reactions to invasive infections, depending largely on the host’s immune status and underlying lung conditions.

Clinical forms include invasive aspergillosis, chronic pulmonary aspergillosis, aspergilloma (a fungus ball that forms in preexisting lung cavities), allergic bronchopulmonary aspergillosis (ABPA), and aspergillosis of the paranasal sinuses. Invasive aspergillosis mainly affects severely immunocompromised individuals, such as those with hematologic malignancies or solid organ transplants. ABPA occurs mainly in people with asthma or cystic fibrosis and involves an allergic response to the organism. Aspergilloma develops in existing lung cavities, often after tuberculosis or other lung diseases.

Risk factors and pathogenesis involve impaired immune defenses, particularly neutropenia and prolonged corticosteroid use, as well as chronic lung diseases, prior lung damage, or environmental exposure. Diagnosis combines clinical assessment with imaging, microbiological culture, and serological tests. CT findings may include nodules with a halo sign or an air crescent sign in invasive disease; aspergillomas appear as a movable fungal mass within a cavity. Serology (galactomannan, 1,3-beta-D-glucan) and histopathology assist in confirming invasive disease, while culture identifies the organism.

Treatment varies by form. Invasive aspergillosis is typically treated first-line with voriconazole or alternatives such as liposomal amphotericin B; therapy is prolonged and may require step-down or combination strategies. ABPA is managed with corticosteroids and may include antifungals. Aspergilloma may require surgical resection in selected cases. Chronic pulmonary aspergillosis often needs long-term antifungal therapy. Prevention focuses on reducing exposure and preventing extension in high-risk patients.