Fungus – North American Blastomycosis

North American Blastomycosis is a “deep fungus” infection which I occasionally encounter in my The Woodlands dermatology and Conroe dermatology clinics. It is caused by a fungus called Blastomyces dermatitides, which is found in the soil and is very prevalent in the Southeastern portion of the United States especially the Ohio and Mississippi river basins.  Beaver dams are a common source of outbreaks, so patients that camp near beaver dams are prone to this infection.  It predominantly infects older men especially with immunosuppression.  In most cases, a patient is infected through the respiratory tract by inhaling the fungus.  It can spread from the lungs to the skin where it appears as a draining thick warty crusty nodule/plaque.  Rarely, can a patient be directly infected through the skin.  Blastomycosis has a characteristic feature under microscopy in which “broad based buds” are seen as the fungus is proliferating.  Treatment of Blastomycosis is with systemic antifungals such as Itraconazole or Amphotericin.