Chromoblastomycosis: Symptoms, Diagnosis and Exams

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Chromoblastomycosis (CBM) is defined as a chronic cutaneous and subcutaneous fungal infection resulting from traumatic implantation of certain dematiaceous fungi through the skin. The aetiological agents gain entrance through transcutaneous puncture wounds, usually by parts of plants.

The definition of CBM is occasionally narrowed to the disease caused by fungus of the Chaetothyriales order. In a typical manifestation the dermal lesions form cauliflower-like nodules. In the infected tissue, characteristic dark-coloured, thick-walled, muriform cells i.e. sclerotic cells (Medlar bodies) are observed, which is a histopathological criterion for the diagnosis.

Chromoblastomycosis Symptoms and Signs

Usually, chromoblastomycosis begins on the foot or leg, but other exposed body parts may be infected, especially where the skin is broken. Early small, itchy, enlarging papules may resemble dermatophytosis (ringworm).

These papules extend to form dull red or violaceous, sharply demarcated patches with indurated bases. Several weeks or months later, new lesions, projecting 1 to 2 mm above the skin, may appear along paths of lymphatic drainage.

Hard, dull red or grayish cauliflower-shaped nodular projections may develop in the center of patches and, if the infection is untreated, gradually extend to cover extremities over the course of many years. Lymphatics may be obstructed, itching may persist, and secondary bacterial superinfections may develop, causing ulcerations and occasionally septicemia.

Chromoblastomycosis Diagnosis

  • Histopathology
  • Culture

Late chromoblastomycosis lesions have a characteristic appearance, but early lesions may be mistaken for dermatophytoses.

Fontana-Masson staining for melanin helps confirm the presence of the sclerotic bodies (Medlar bodies), which are pathognomonic. Culture is needed to identify the causative species.

Chromoblastomycosis Treatment

  • Itraconazole, sometimes with flucytosine
  • Often surgery or cryotherapy
  • Antifungal Drugs.

Itraconazole is the most effective drug for chromoblastomycosis, although not all patients respond. Flucytosine is sometimes added to prevent relapse. Amphotericin B is ineffective. Anecdotal reports suggest that posaconazole, voriconazole, or terbinafine may also be effective.

Physical examination

A 55-year-old man presented with vegetating lesions on the right foot that had been slowly enlarging during the past several years

several nodular and verrucous lesions were seen in the distal region of the foot. The patient lived in a rural area and had walked barefoot for most of his life. Analysis of a skin-biopsy specimen revealed clusters of small, round, thick-walled, brown sclerotic bodies in the stratum corneum (muriform cells), which are diagnostic for chromoblastomycosis.

Chromoblastomycosis is a chronic, soft-tissue fungal infection commonly caused by Fonsecaea pedrosoi, Phialophora verrucosa, Cladosporium carrionii, or F. compacta. The infection occurs in tropical or subtropical climates and often in rural areas. The fungi are usually introduced to the skin through cutaneous injury from thorns, splinters, or other plant debris. The patient was treated with multiple surgical excisions and itraconazole for 24 months with a complete resolution of symptoms.

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