Mycetomas are chronic granulomatous infections that can progress from subcutaneous to more invasive disease. They are normally found in soil, standing water, and sewage, and are acquired through accidental traumatic implantation. They are often found in tropical areas, or in people who work outdoors and get frequent injuries. The most common ones in the U.S. are Pseudallesheria boydii and Acremonium spp., a cause of “white grain mycetoma”. Though sometimes considered dematiaceous because they can have somewhat darker colors, they are actually hyaline molds and are covered under hyaline molds in this course.
Chromoblastomycosis is also induced by traumatic inoculation, and manifests as a papule at the site of injury, which can cause ulceration. It can spread through the lymphatic system. The lesions contain characteristic sclerotic bodies. These infections are found frequently in tropical areas, but occasional cases are found in the U.S., especially among agricultural workers.
Phaeohyphomycosis refers to an infection caused by dematiaceous molds other than those above. The clinical manifestations include: brain abscess, sinusitis, endocarditis, and systemic infection. Many can cause neurological symptoms, including Cladophialophora, Exophiala, and Curvularia spp.