Merck Manual

Please confirm that you are a health care professional

honeypot link



Paschalis Vergidis

, MD, MSc, Mayo Clinic College of Medicine & Science

Reviewed/Revised Sep 2023
Topic Resources

Chromoblastomycosis is a specific type of cutaneous infection caused by one of several species of dematiaceous (pigmented) fungi. Symptoms are ulcerating nodules on exposed body parts. Diagnosis is by appearance, histopathology, and culture. Treatment is with itraconazole, another mold-active azole, or terbinafine and surgical excision.

Chromoblastomycosis is a cutaneous infection affecting immunocompetent people, mostly in tropical or subtropical areas; it is characterized by formation of papillomatous nodules that tend to ulcerate.

Chromoblastomycosis often occurs at the site of penetrating injury, particularly in farmers and other agricultural workers without adequate protective footwear and clothing.

Chromoblastomycosis is caused by dark brown or black fungi that produce sclerotic bodies in tissue.

Symptoms and Signs of Chromoblastomycosis

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 Overview of Dermatophytoses Dermatophytoses are fungal infections of keratin in the skin and nails (nail infection is called tinea unguium or onychomycosis). Symptoms and signs vary by site of infection. Diagnosis is by... read more (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.

Manifestations of Chromoblastomycosis

Diagnosis of Chromoblastomycosis

  • 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.

Treatment of Chromoblastomycosis

  • Itraconazole

  • Terbinafine

  • Often surgery or cryotherapy

Itraconazole is the most effective medication for chromoblastomycosis, although not all patients respond. Flucytosine is sometimes added to prevent relapse. Flucytosine should not be used as monotherapy.

Anecdotal reports suggest that posaconazole, voriconazole, or terbinafine may also be effective.

Amphotericin B is ineffective.

For localized lesions, surgical excision may be curative.

Adjunctive therapies such as cryotherapy are often helpful, although response is slow.

Drugs Mentioned In This Article

Drug Name Select Trade
Desenex Max, Lamisil, Lamisil AT, Lamisil AT Athletes Foot, Lamisil AT Jock Itch, Terbinex
Amphocin, Fungizone
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
quiz link

Test your knowledge

Take a Quiz!