This may be the best review of blastomycosis I've read.
Some key points:
Unlike many other fungal infections blasto is not an opportunist. The typical patient profile is the healthy outdoorsy woodsman type. Anyone can be afflicted with severe disease.
Blasto is a great mimicker. In the lungs it can present as community acquired pneumonia, ARDS, nodules, just about anything. Skin manifestations include verrucous lesions, ulcerative lesions (e.g. resembling pyoderma gangrenosum), subcutaneous nodules resembling panniculitis among others. Involvement of other organs is also seen.
The author states:
This infection causes manifestations which mimic many other more commonly diagnosed conditions and must always be considered by clinicians practicing in the endemic region.