Chromoblastomycosis
Definition
- Infection of cutaneous and subcutaneous tissues caused by dematiaceous fungi
- Common agents include:
- Fonsecaea pedrosoi
- Phialophora verrucosa
- Cladosporium carrionii
- Rhinocladiella aquaspersa
- All our saprophytic fungi found in:
- Soil
- Wood
- Vegetation
- Paper
Presentation of the disease
- Lesions form at site of inoculation and grow slow
- Asymptomatic in most cases
- If symptoms are present they include:
- Pruritis
- Pain (rare)
- Lesions usually present months to years before patients seek medical attention for diagnosis
Common Anatomical Sites
- Lower extremities (most common)
- Foot
- Ankle
- Lower leg
- May cause elephantiasis of infected limbs
- Also found on other sites such as:
- Abdomen
- Chest
- Back
- Face
- Mucous membranes (rare)
- Most lesions are localized, but may spread through scratching or lymphatic spread
- Disseminated disease has only been shown in less than 5% of patients
Lesions of Chromoblastomycosis
- Initial lesions are small nodules that eventually form irregular, verrucous plaques.
- Five types of lesions present during progression:
- Nodular- pink scaly growths; enlarge to form tumor
- Tumorous- papillomatous and lobular; resemble cauliflower
- Verrucous- (most common) wart-like appearance
- Plaque – slightly raised; scaly and pink to reddish
- Cicatrical- large and serpiginous; scar found in center of lesion
Complications
- May lead to secondary bacterial infection
- Bacterial infection symptoms:
- Fever
- Pain
- Edema
- Localized lymphadenopathy
Laboratory Aspects
Causative Agent
-Chromoblastomycosis is caused by a few of the species dematiaceous, the most common organism is Fonsecaea Pedrosoi.
-Other agents include: Fonsecaea compacta, Cladophialophora carrionii, Phialophora verrucosa, and Rhinocladiella aquaspersa
-Dematiaceous fungi causing chromoblastomycosis are slow growing and usually need to be incubated
-Most species form dark brown, green, or black velvety colonies upon incubation
Virulence Factors
-Infection occurs through minor breaks in the skin
-Most patients that are infected cannot recall the event in which they were infected
-Person to person spread of chromoblastomycosis has not as of yet been documented
-Diagnosis of chromoblastomycosis is based on results from typical skin lesions and the presence of sclerotic bodies from examination
Epidemiology and Ecology
∙ Found in soil and woody plant material in tropical and subtropical climates
∙ Occurs with traumatic implantation of fungal elements into the skin
∙ Rural areas, most commonly associated with agricultural related activities
∙ Immunocompromised
∙ Immunosuppressed
-received organ transplants
∙ Low incidence in children
-theory that the spores lie dormant in the tissue for many years
∙ Rarely in animals
-unknown if there is transfer from animals to humans
Histopathology
-The lesion shows a chronic inflammatory response. Dematiaceous (darkly pigmented) hyphae and sclerotic (hard or hardening) bodies are found in the outmost layer of the epidermis. These hardening bodies are round, thick-walled,chestnut brown, and 5-12 µm in diameter.
Treatment
∙ Early treatment
-surgical excision – necessary to take unaffected areas too and recurrence is common with this treatment
-electrodessication
-cryosurgery
-topical heat
∙ inexpensive
-anti-fungal treatment
∙ Thiabendazole
∙ 5-flurocytosine
∙ Amphotericin B
∙ Advanced cases- systemic treatment
-Itraconazole
-Terbinafine
Case Report: Bangladeshi man
∙ 70 year old Bangladeshi man
-lived in Britain for 50 years
-referred with a lesion on right forearm
∙ Lesion occurred 40 years prior
-excised and grafted in India
∙ 1993 lesion reoccurred
-no past medical history or regular medication
-examination revealed a hardened plaque with central crusting
∙ Skin scrapings taken
-microscopy was negative
∙ Skin biopsy
-pseudoepitheliomatous hyperplasia and dermal infiltrate with granuloma formation
-higher power showed Langhans giant cells with characteristic sclerotic bodies
-diagnose as chromoblastomycosis
∙ Patient lost for follow-up when he returned to India for holiday
-returned about 6 months later and started Itraconazole
-lost again for follow-up
Case Report: A clinical and mycological study of 71 cases from
Sri Lanka
- Attapattu, Mycopathologia. (1997) 137: 145–151
-Data collected by Mycology Division of the Medical Research Institute
-71 cases of patients with chromoblastoycosis were detected over a 16 year period
-67 of these had thick walled microscopic pheoid muriform cells from superficial crusts or biopsies.
-69 of the patients had positive cultures.
-2 patients were diagnosed via microscopy alone.
-Disease duration last from one month to 25 years,
- 43/71 received medical advice within 5 years, 13/71 patients after 10 years and 3/71 patients waited 20 years.
-Majority of patients came from Ratnapuraand were involved in agricultural work or gem mining
- Lesions were seen mostly on lower limbs on 55 out of 77 patients.
-Foot lesions were only on 19 out of 77 patients.
-Lesions were at multiple locations in 5 out of the 77 cases.
-Treatment
-5 fluorocytosine at a dose of 1200 mg a day was distributed to patients infected by F. pedrosoi and results were seen within 3 weeks.
-One male patient, infected by P. verrucosa,was treated with 5 fluorocytosine and local dressing of miconazole nitrate solution. Complete healing occurred after three weeks and he was sent home after 4 weeks. He was lost for a follow up visit.
Case Report
Background
-70 yr old male agriculturist
-Had a history of painless a verrucous lesion on the middle of his leg
-Experienced this lesion for 1 year after an abrasion from a coconut tree
-Had a skin biopsy and it showed that there was evidence of fungal elements
Diagnosis and Treatment
-Cladophialophora was isolated from the culture that was taken
-Because of this, chromoblastomycosis was diagnosed
-The patient was first treated with itraconazole, however there was no response
-Because there was no response complete surgical resection of the lesion was performed
-Follow-up examination was done after one year and the lesion was absent
Discussion
-Chromoblastomycosis mostly occurs in adult males ages 30-50 yrs old
-Infection is usually present in the leg and feet
-This is a slowly progressing lesion and average time of diagnosis is roughly 1-4 yrs after the injury
-Antifungal treatment is performed first, and if there is no response then surgery is performed
References
TopleyandWilson'sMicrobiologyandMicrobialInfections,10thedition.2005.Vol3.MedicalMycology.Hodder,Arnold
and June 19, 2008)