Chromoblastomycosis

Chromoblastomycosis is a chronic fungal infection in which there are raised crusted lesions affecting the skin and subcutaneous tissue. It usually affects the limbs.

Chromoblastomycosis may be due to several fungi found in soil, wood and decaying plant material.

The organism is inoculated into the skin by a minor injury, for example, a cut with a splinter when barefoot. It is exceedingly rare in New Zealand, but relatively common in warmer areas such as the Pacific Islands.

The most common names of the most common organisms are:

Phialophora verrucosa
Fonsecaea pedrosi
Fonsecaea compacta
Cladosporium carrionii
Rhinocladiella aquaspersa (Ramichloridium cerophilum)

Extensive long
standing chromoblastomycosis
in Fijian

Warty thickened
skin due to
chromoblastomycosis

Chromoblastomycosis
on a toe

Clinical features

Chromoblastomycosis generally presents as a single lesion on an exposed site such as the foot or hand.

It starts as a small firm red or grey bump.
It grows very slowly: only about 2mm per year.
Eventually a warty dry nodule or plaque develops.
There may be at least partial clearing with scarring in the centre of the lesion.
The affected limb can enlarge generally (elephantiasis).
New lesions may develop in time as satellites around the first one or the infection may be scratched into a new site.
It may cause no discomfort but is frequently very itchy.
Rarely, squamous cell carcinoma (SCC) develops within longstanding chromoblastomycosis.

The infection is sometimes confused with other skin conditions such as:

Other fungal infections such as sporotrichosis
Bacterial infections such as atypical mycobacterium infection, tuberculosis, leprosy and syphilis
Protozoal infections such as leishmaniasis
Squamous cell carcinoma
Skin disorders such as psoriasis, discoid lupus erythematosus.