Reappearance of Sporothrix schenckii lesions after administration of Solu-Medrol R to infected cats.

In 10 of 34 adult cats infected with Sporothrix schenckii, demonstrable lesions healed spontaneously in 31 to 88 days after inoculation of the organism. None of 5 untreated cats developed additional visible lesions during the period of observation, nor were they positive for S. schenckii by culture at necropsy. Five animals were treated with Solu-Medrol R to determine if the apparent clinical cure was also accompanied by a mycological cure. Lesions reappeared at, or near, the site of the original lesions in 3 of the 5 treated cats from 4 to 6 months after the initial lesions healed. Fungi were cultured both from the regional lymph node and from exudate of the skin lesions. Thus, it appears that viable S. schenckii may be sequestered in tissues for at least 6 months without showing clinical evidence of their presence. Moreover, apparently "healed" lesions may be reactivated and progress to typical demonstrable skin lesions following immuno-suppression.