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Chromoblastomycosis

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.

Chromoblastomycosis

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Chromoblastomycosis

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Chromoblastomycosis

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Chromoblastomycosis

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.
Chromoblastomycosis

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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.

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High power view of histology.

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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.

  • Flucytosine
  • Thiabendazole
  • Local heat
  • Cryotherapy
  • Surgery to remove the affected tissue completely.