Pulmonary and sinus fungal diseases in non-immunocompromised patients

The human respiratory tract is exposed daily to airborne fungi, fungal enzymes and secondary metabolites. The endemic fungi Histoplasma capsulatum, Coccidioides spp., Blastomyces dermatitidis and Paracoccidioides brasiliensis, and occasionally Aspergillus fumigatus, are primary pulmonary pathogens of otherwise healthy people. The majority resolve such infections, few develop disease. However, many fungi are directly allergenic by colonizing the respiratory tract, or indirectly through contact with cell wall constituents and proteases, causing or exacerbating allergic disease. Increasing evidence implicates high indoor fungal exposures as a precipitant of asthma in children, and in worsening asthma symptoms. Lung or airways infection by endemic fungi or Aspergillus can be diagnosed with respiratory sample culture or serum IgG antibody testing. Sputum, induced sputum or bronchial specimens are all suitable specimens for detecting fungi; microscopy, culture, galactomannan antigen and Aspergillus PCR are useful tests. Antifungal treatment is indicated in almost all patients with chronic cavitary pulmonary infections, chronic invasive and granulomatous rhinosinusitis and Aspergillus bronchitis. The majority of patients with fungal asthma benefit from antifungal therapy. Adverse reactions to oral azoles, drug interactions and azole resistance in Aspergillus spp. limit therapy. Environmental exposures, genetic and structural pulmonary risk factors probably underlie disease, but are poorly understood.