Blastomycosis acquired by three children in Toronto

Area of Science:

• Mycology
• Paediatric Infectious Diseases
• Epidemiology

Background:

• Blastomycosis is a fungal infection caused by *Blastomyces dermatitidis*, endemic to certain regions of North America.
• Diagnosis in children is rare and often delayed, particularly when acquired outside known endemic zones.
• Clinical suspicion for blastomycosis is often low in non-endemic areas.

Observation:

• Three paediatric cases of blastomycosis acquired in or near Toronto, Ontario, are presented.
• The disease was not initially suspected clinically in any case, leading to diagnostic delays.
• Pulmonary involvement was noted in all three patients; one also had multifocal osteomyelitis.

Findings:

• Broadening diagnostic methods to include fungal and mycobacterial cultures aided in diagnosis.
• Successful treatment was achieved with amphotericin B and/or itraconazole.
• The cases suggest blastomycosis may occur in children outside previously accepted geographical boundaries.

Implications:

• Blastomycosis should be considered in the differential diagnosis for paediatric patients in the Toronto area with compatible symptoms, even without a history of travel to endemic zones.
• This study underscores the importance of considering less common pathogens in paediatric respiratory and bone infections.
• Expanded geographical surveillance and diagnostic awareness are crucial for timely blastomycosis diagnosis in children.