Blastomycosis

I saw a case of cutaneous blastomycosis in clinic today -- two lesions, one on the face, the other on the buttock in an otherwise healthy male patient.  A nice review is here.

Blastomycosis is a dimorphic (mould at room temperature, yeast at body temperature) fungus which is endemic in certain geographic areas of North America.  Ontario, where I currently live, and in particular northwest Ontario by the Manitoba border is one such geographic hot spot.

The most common sites of infection are:

• Pulmonary (most patients have some pulmonary involvement)
• Presents as acute (including ARDS) or chronic pneumonia, pulmonary nodule, asymptomatic
• Cutaneous (in 40-80% of cases) presenting as verrucous or ulcerative skin lesions (like my patient)
• Osteomyelitis (~25% of extrapulmonary) presenting as painful lesion in bone, which can mimic sarcoma in radiographic appearance.  Occasionally can have concomittant septic arthritis in adjacent bone.
• GU: (10-30%) in men prostate, testicle, epididymis.
• CNS (5-10%), usually chronic meningitis, occasionally space occupying lesions
• Other

Treatment is with amphotericin B for severe disease (or CNS induction) or with azoles (itraconazole or voriconazole) for other forms.  Treatment guidelines from the IDSA are available here.