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Fungal Infections

Disease name and synonyms

Chromoblastomycosis (chromomycosis)

Fungi responsible (links to these)

Many melanised (black fungi) fungal species can be the etiologic agents of this disease. The most frequent are:  Fonsecaea pedrosoi and Cladophialophora carrionii. Less common species involved are Phialophora verrucosa, Rhinocladiella aquaspersa, Exophiala spp and new Fonsecaea species.  F. compacta is now incorporated into the Fonsecaea pedrosoi complex. 

Disease description

It is a cutaneous and subcutaneous mycosis characterized by the appearance of proliferating chronic skin lesions following traumatic implantation of the fungus. Sites most commonly affected are the lower limbs. Upper limbs and buttocks are also frequently involved. Ear, face, neck and breasts have been reported sporadically. Lesions start as nodule or papule that slowly enlarge becoming verrucose and wart-like. Old lesions can be tumorous or cauliflower-like in appearance. Lymphatic and hematogeneous dissemination have been described but they are infrequent.

Frequency and global burden

Worldwide but the frequency is much higher in tropical and subtropical areas of Africa, Central and South America, Asia and Australia. Global burden is unknown but in high endemic areas the incidence can reach 16 cases x 100.000 inhabitants.

Underlying problems and at risk patients

This disease is occupational and related with any activity where traumatic injury with contaminated material is frequent as agricultural work.

Diagnostic testing

Clinical observation is not useful to establish the diagnosis. Skin scrapings or a biopsy should be taken from the lesions. Skin scrapings should be examined using 10% KOH and Parker ink or calcofluor white. Tissue sections should be stained with hematoxylin and eosin, PAS, and silver stains. To establish a diagnosis of chromoblastomycosis, rounded sclerotic bodies, planate dividing and brown pigmented, should be observed in the clinical samples. To identify the etiologic agent, clinical samples should be cultured on isolation media as Sabouraud agar. Great expertise is needed to identify these fungi to species level. It is advisable to perform the identification by means of ITS sequencing.

Treatments

No optimal treatment has been identified but the sooner the diagnosis and treatment is made, the better rate of cure. Many patients look for help after many years of disease evolution. Cryosurgery is a good option when the lesions are small. Itraconazole 200-400 mg/day is another option especially when the lesions are large. Patients usually improve but complete cure is rare. In addition, many cases require years of treatment, which is highly costly. Therapeutic drug monitoring (TDM) could improve the rate of success. In some cases, itraconazole combined with flucytosine has been used with good results. Terbinafine has been reported to have a similar success rate than that obtained with itraconazole. Posaconazole, 800 mg/day has also been used for the treatment of chromoblastomycosis with a success rate in refractory disease of 82% (small number of patients). TDM may improve the success rate of posaconazole.

Outlook and prognosis

Small and localized lesions have a good prognosis. Cure is difficult when the lesions are large. Most common complications are ulceration and secondary infections and lymphoedema.

Images


Facial chromoblastomycosis from Papua New Guinea

chromoblastomycosis
Severe facial and ear chromoblastomycosis in a man from Papua New Guinea

chromoblastomycosis of arm


Chromoblastomycosis of the arm (above) and leg (below) in a woman from Papua New Guinea.

chromoblastomycosis of leg

(Click image to enlarge) Chromoblastomycosis of the face before   and after (bottom)  treatment for 4 years with posaconazole. Posaconazole is a powerful antifungal, but treatment failed to give a significant inprovement in the lesions. (Courtesy of Dr Flavio, Brazil)

 

 

 

 

 

 

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