Endogenous activation in blastomycosis.

Area of Science:

• Mycology
• Infectious Diseases
• Pulmonology

Background:

• Blastomycosis, a fungal infection caused by Blastomyces dermatitidis, typically enters through the lungs.
• Initial pulmonary infection may resolve, progress, or disseminate to other sites.
• Disseminated blastomycosis often presents without evident pulmonary lesions on chest roentgenograms.

Observation:

• Three patients with disseminated blastomycosis presented with negative chest roentgenograms at diagnosis.
• All three patients had a documented history of pneumonia consistent with blastomycosis months prior.
• Post-bronchoscopy sputum samples revealed Blastomyces dermatitidis yeasts.

Findings:

• These cases provide the first evidence of apparent endogenous activation in blastomycosis.
• The findings suggest a potential for dormant fungal reactivation.
• Histopathological similarities to chronic granulomatous diseases like tuberculosis are noted.

Implications:

• This study suggests blastomycosis reactivation may occur, even years after the initial infection.
• Clinicians should consider blastomycosis in disseminated disease presentations, especially with a prior history of pneumonia.
• Further research into the mechanisms of blastomycosis reactivation is warranted.