Experimental tinea versicolor in rabbits and humans with Pityrosporum orbiculare.

The purpose of this investigation was to produce experimental tinea versicolor in rabbits and humans with Pityrosporum orbiculare. Inoculation with P. orbiculare under plastic occlusion on the glabrous follicle-rich inside of the rabbit ear resulted in a tinea versicolor-like lesion after 1 week in 3 of 4 animals. One week after inoculation with P. orbiculare under plastic occlusion, experimental infections similar to those found clinically in tinea versicolor were seen in 10 of 12 patients with a history of tinea versicolor and in 3 of 6 normal volunteers. It was not possible to produce experimental infections without occlusion. Spontaneous healing usually occurred.