Hyphae are darkly pigmented and contain numerous intercalary chlamydoconidium-like cells. Ascostromata are pseudoparenchymatous structures which are subglobose to irregular in shape and black in color. Each usually contains a single ascus. Asci are ellipsoid, solitary or in clusters and contain 8 ascospores. Ascus walls dissolve readily.
Ascospores are hyaline to darkly pigmented.
No special precautions other than general laboratory precautions are required. Very few data are available and there is as yet no standard method for in vitro susceptibility testing of Piedraia spp. Shaving of affected hair, topical salycylic acid, formaldehyde or azole creams are currently applied for treatment of black piedra. Oral ketoconazole or terbinafine may also be used.