Chromoblastomycosis
Chromoblastomycosis is a chronic fungal infection of the skin, primarily caused by a group of dematiaceous fungi found in soil and decaying vegetation. This infection most commonly affects individuals in tropical and subtropical regions, particularly among barefooted rural populations in Africa and South America. The disease usually targets the lower extremities, often initiating at sites of minor injuries such as cuts or splinters. Initial symptoms include small, painless bumps that can develop into raised, wart-like lesions, which may coalesce into a large, cauliflower-like rash over time. Complications can arise from severe cases, potentially leading to lymphatic stasis, elephantiasis, and even cerebral chromoblastomycosis if the infection spreads. Diagnosis is primarily through the microscopic examination of infected tissue, which reveals characteristic sclerotic bodies. Treatment can be challenging and may involve a combination of surgical interventions and antifungal medications like intraconazole and terbinafine. Preventative measures focus on avoiding exposure to environments where the fungi thrive, particularly by not walking barefoot in wooded areas.
Chromoblastomycosis
- ANATOMY OR SYSTEM AFFECTED: Skin
Definition
Chromoblastomycosis is a chronic fungal infection of the skin caused by a group of dematiaceous, or darkly pigmented, fungi found in soil and decaying vegetation. The incidence of the disease is higher in bare-footed rural populations of tropical and subtropical areas of Africa and South America. This type of infection usually affects the limbs, especially the lower extremities, where the skin is broken.
Causes
Several species of dematiaceous fungi cause chromoblastomycosis. These include several species each of Fonsecaea, Cladophialophora, Exophiala, Phialophora, and Rhinocladiella. Infection occurs when the fungus is traumatically implanted under the skin through minor injuries such as a cut with a splinter, thorn, or other plant debris. Infected persons rarely seek medical care because the trauma often goes unnoticed and because the progression of the disease is slow.
Risk Factors
All ages may be affected by the disease. The majority of reported cases, however, involve healthy males with an outdoor hobby or occupation such as agricultural work. Immunocompromised persons are more likely to have a severe form of the disease.
Symptoms
Chromoblastomycosis initially begins with small, painless, sometimes itchy, bumps on lower extremities at the site of implantation. Lesions may be wartlike, ulcerated, tumorlike, crusted, flat, or raised. Infections are localized and can progress slowly over many years. Satellite lesions may develop on other areas (hands, arms, buttocks, ears, face, and breasts) and coalesce to form a large cauliflower-like rash that gradually covers the extremities. In severe cases, complications can arise; these include elephantiasis and secondary bacterial infections that result in lymphatic stasis (lymph fluid retention) and sepsis (bloodstream infection). Dissemination to the brain known as cerebral chromoblastomycosis may also occur.
Screening and Diagnosis
Chromoblastomycosis is a long-term fungal infection of the skin, sometimes confused with blastomycosis, lobomycosis, paracoccidioidomycosis, or sporotrichosis. Primary care physicians should consult with an infectious disease specialist or pathologist for early diagnosis and treatment. Diagnosis involves isolation, microscopic examination, morphological testing, and culture of infected specimens for characteristic brown-colored, round, thick-walled, sclerotic bodies. These sclerotic bodies resemble copper pennies and are characteristic of the dematiaceous fungi responsible for chromoblastomycosis. Blood analysis and imaging studies are not frequently used for diagnosis.
Treatment and Therapy
Treatment of chromoblastomycosis is long and difficult. Depending on the extent and severity of the disease, treatment includes surgical excision, heat, electric current, cryosurgery, and antifungal therapy. Intraconazole, terbinafine, and flucytosine are the drugs of choice. A chromoblastomycosis infection is rarely fatal.
Prevention and Outcomes
The etiologic agents of chromoblastomycosis are everywhere. The best form of prevention is to avoid walking barefoot in wooded areas, especially where the fungus is prevalent.
Bibliography
Centers for Disease Control and Prevention. "Clinical Overview of Chromoblastomycosis." CDC, 15 Aug. 2024, www.cdc.gov/chromoblastomycosis/hcp/clinical-overview/index.html. Accessed 4 Nov. 2024.
Esterre, Phillippe, et al. "Chromoblastomycosis: An Overview of Clinical Manifestations, Diagnosis and Treatment." Medical Mycology, vol. 47, no. 1, 2009, pp. 3-15, doi.org/10.1080/13693780802538001. Accessed 4 Nov. 2024.
Hamza, Sate H., et al. "An Unusual Dematiaceous Fungal Infection of the Skin Caused by Fonsecaea pedrosoi: A Case Report and Review of the Literature." Journal of Cutaneous Pathology, vol. 30, 2003, pp. 340-343.
Krzyściak, Przemysław M., et al. "Chromoblastomycosis." Postępy Dermatologii i Alergologii, vol. 31, no. 5, Oct. 2014, pp. 310-321. PubMed Central, doi:10.5114/pdia.2014.40949. Accessed 4 Nov. 2024.
Kurien, George, et al. "Chromoblastomycosis - StatPearls." NCBI, 1 Mar. 2024, www.ncbi.nlm.nih.gov/books/NBK470253. Accessed 4 Nov. 2024.
Richardson, Malcolm D., and Elizabeth M. Johnson. Pocket Guide to Fungal Infection. 2nd ed., Wiley-Blackwell, 2006.
St. Georgiev, Vassil. Opportunistic Infections: Treatment and Prophylaxis. Humana Press, 2003.