There are two groups of diseases that bear the title histoplasmosis. The far more common use of this term is to refer to the forms of histoplasmosis caused by Histoplasma capsulatum var. capsulatum. This organism was formerly known simply as Histoplasma capsulatum, and its diseases have also been referred to as North American Histoplasmosis. This organism most often causes pulmonary disease, although disseminated forms are also well known.
The other form is that of histoplasmosis caused by Histoplasma capsulatum var. duboisii. This organism was formerly known simply as Histoplasma duboisii, and its diseases have also been referred to as African Histoplasmosis. This organism most often causes skin and bone disease.