Mycology Practice Exam

Sporothrix schenckii is the fungus that causes sporotrichosis, a subcutaneous fungal infection typically arising after a puncture through the skin with plant material (like a rose thorn) or contaminated wood. The infection usually begins as a localized skin lesion and can ascend along the lymphatic channels, producing a chain of nodules called lymphocutaneous spread. The organism is dimorphic—existing as mold with rosette-arranged conidia in the environment and as yeast in human tissue—which helps explain its behavior and appearance in tissue samples. This pattern of inoculation and lymphatic spread is characteristic, and it contrasts with the inhalational diseases caused by Histoplasma, Coccidioides, or Blastomyces, which present with pulmonary or systemic symptoms rather than localized skin and lymphatic lesions. Therefore, Sporotrichosis is the disease caused by Sporothrix schenckii.