As an unreported, sporadic disease, its incidence is difficult to estimate. The mold itself is endemic to the Missouri and the Mississippi River Valleys. Sporotrichosis is rare in Europe. Scarring can result at ulcerated sites. Systemic infections can be life threatening, especially in the immunocompromised host.
Most patients relate a history of a recent prick injury at the site of infection.
The injuries are attributed to a variety of causes, including rose thorns, hay, sphagnum moss, conifer needles, mine timbers, and infected cats. The characteristic skin lesion is a dermal or subcutaneous nodule that may ulcerate. As the infection spreads along the regional lymphatic chain, satellite nodules develop along with associated regional lymphadenopathy. The infection may disseminate to cause systemic disease. Symptoms usually arise within 3 weeks of injury.