Blastomycosis is a fungal infection caused by a dimorphic (has two forms) fungus termed Blastomyces dermatitidis. It primarily affects the lungs but it can be spread to other parts of the body such as skin, bones, reproductive and urinary tracts, and tissues covering the brain. Immunocompromised patients, travellers and those who dwell in dense wooded areas are at high risk of this infection.