What is chromoblastomycosis?
Chromoblastomycosis is a chronic mushrooms infection in which there are high crusted lesions affecting the skin and subcutaneous tissue. It usually affects the extremities.
What causes chromoblastomycosis?
Chromoblastomycosis can be caused by various fungi found in decomposing soil, wood, and plant material.
the organism it is inoculated on the skin from a minor injury, for example, a cut with a splinter when barefoot. It is extremely rare in New Zealand, but relatively common in warmer areas like the Pacific Islands.
The most common organisms They are:
- Phialophora verrucosa
- Fonsecaea pedrosi
- Fonsecaea compact
- Cladophialophora carrionii
- Rhinocladiella aquaspersa (Ramichloridium cerophilum)
What are the clinical characteristics of chromoblastomycosis?
Chromoblastomycosis usually presents as a single injury in an exposed place like the foot or the hand.
- It begins as a small firm red or gray bump.
- It grows very slowly: only about 2mm per year.
- Finally a warty dry nodule or license plate it develops
- There may be at least a partial clearance with scars in the center of the injury.
- The affected limb can be enlarged in general (elephantiasis).
- New lesions can develop in time as the satellites around the first one or the infection can be scratched at a new site.
- It may not cause discomfort, but it is often very itchy.
- Rarely, scaly cell carcinoma (SCC) develops within long-standing chromoblastomycosis.
The infection is sometimes mistaken for other skin conditions, such as:
- Other fungal infections like sporotrichosis
- Bacterial infections like atypical mycobacterial infection, tuberculosis, leprosy, and syphilis
- Protozoal infections such as leishmaniasis.
- Squamous cell carcinoma
- Skin disorders like psoriasis, discoid lupus erythematosus.
How is chromoblastomycosis diagnosed?
Histopathology of chromoblastomycosis may show the typical thick-walled dark brown color 'sclerotic'cells in the skin biopsy confirming the presence of a dematiaceous fungus. It is dark in color due to melanin on the walls of the body.
Culture in Sabouraud medium with antibiotics at 25–30 degrees centigrade, colonies of olive-green to black fungi grow after one or two weeks. Naming the responsible fungus can be difficult. Phaeohyphomycosis is the name given to an infection caused by dematiaceous fungi.
High power view of histology.
Cladophialophora carrionii grown on Sabouraud dextrose agar with antibiotics
What is the treatment for chromoblastomycosis?
Rarely, chromoblastomycosis resolves spontaneously leaving a scar.
Treatment is difficult and long. It may include:
Itraconazole, posaconazole or voriconazole, possibly in combination with terbinafine.
- Local heat
Surgery to remove the affected tissue completely.