A halo around the organisms is frequently observed. Langhans giant cells are common. There is some indication that the number of organisms increases with chronicity. Budding is often seen. Mycelial forms within lesions occur infrequently.
Aerial forms occur, but are rare.
There are published reports of various tests to detect antibodies as well as a skin hypersensitivity test for detection of cell-mediated immunity. Make antigen slides by smearing the lesion contents on to a glass slide or by emulsifying the cultured yeast phase of the organism in a saline solution and creating a thin film on a glass slide. Heat fix by passing the slide through a flame. Wash in PBS three times for 10 minutes each. Wash in PBS three times for 10 minutes each.