Chromoblastomycosis is a long-term

fungal infection Fungal infection, also known as mycosis, is disease caused by fungi. Different types are traditionally divided according to the part of the body affected; superficial, subcutaneous, and systemic. Superficial fungal infections include common ti ...

of the skin and

subcutaneous tissue The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and m ...

(a chronic

subcutaneous mycosis Fungal infection, also known as mycosis, is disease caused by fungi. Different types are traditionally divided according to the part of the body affected; superficial, subcutaneous, and systemic. Superficial fungal infections include common ...

). It can be caused by many different types of

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...

which become implanted under the

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

, often by thorns or splinters. Chromoblastomycosis spreads very slowly. It is rarely fatal and usually has a good

prognosis Prognosis ( Greek: πρόγνωσις "fore-knowing, foreseeing") is a medical term for predicting the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) or remain sta ...

, but it can be very difficult to cure. The several treatment options include medication and surgery. The infection occurs most commonly in tropical or subtropical climates, often in rural areas.

Symptoms and signs

The initial trauma causing the infection is often forgotten or not noticed. The infection builds at the site over a period of years, and a small red

papule A papule is a small, well-defined bump in the skin. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some h ...

(skin elevation) appears. The lesion is usually not painful, with few, if any symptoms. Patients rarely seek medical care at this point. Several complications may occur. Usually, the infection slowly spreads to the surrounding tissue while still remaining localized to the area around the original wound. However, sometimes the fungi may spread through the

blood vessels The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...

lymph vessels The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vessel ...

, producing

metastatic Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, ...

lesions at distant sites. Another possibility is secondary infection with

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

. This may lead to lymph stasis (obstruction of the lymph vessels) and

elephantiasis Elephantiasis is the enlargement and hardening of limbs or body parts due to tissue swelling. It is characterised by edema, hypertrophy, and fibrosis of skin and subcutaneous tissues, due to obstruction of lymphatic vessels. It may affect the genit ...

. The nodules may become ulcerated, or multiple nodules may grow and coalesce, affecting a large area of a limb.

Cause

Chromoblastomycosis is believed to originate in minor trauma to the skin, usually from vegetative material such as thorns or splinters; this trauma implants fungi in the subcutaneous tissue. In many cases, the patient will not notice or remember the initial trauma, as symptoms often do not appear for years. The fungi most commonly observed to cause chromoblastomycosis are: * ''

Fonsecaea pedrosoi ''Fonsecaea pedrosoi'' is a fungal species in the family Herpotrichiellaceae, and the major causative agent of chromoblastomycosis. This species is commonly found in tropical and sub-tropical regions, especially in South America, where it grows a ...

'' * '' Cladophialophora bantiana'' causes both cutaneous chromoblastomycosis and systemic

phaeohyphomycosis Phaeohyphomycosis is a diverse group of fungal infections, caused by dematiaceous fungi whose morphologic characteristics in tissue include hyphae, yeast-like cells, or a combination of these. It can be associated an array of melanistic filamentou ...

* ''

Phialophora verrucosa ''Phialophora verrucosa'' is a pathogenic, dematiaceous fungus that is a common cause of chromoblastomycosis. It has also been reported to cause subcutaneous phaeohyphomycosis and mycetoma in very rare cases. In the natural environment, it can ...

'' * ''

Cladophialophora carrionii ''Cladophialophora carrionii'' is a melanized fungus in the genus ''Cladophialophora'' that is associated with decaying plant material like cacti and wood. It is one of the most frequent species of ''Cladophialophora'' implicated in human diseas ...

'' * ''

Fonsecaea compacta ''Fonsecaea compacta'' is a saprophytic fungal species found in the family Herpotrichiellaceae. It is a rare etiological agent of chromoblastomycosis, with low rates of correspondence observed from reports. The main active components of ''F. com ...

Mechanism

Over months to years, an erythematous papule appears at the site of inoculation. Although the mycosis slowly spreads, it usually remains localized to the skin and subcutaneous tissue. Hematogenous and/or lymphatic spread may occur. Multiple nodules may appear on the same limb, sometimes coalescing into a large plaque. Secondary bacterial infection may occur, sometimes inducing lymphatic obstruction. The central portion of the lesion may heal, producing a scar, or it may ulcerate.

Diagnosis

The most informative test is to scrape the lesion and add

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...

(KOH), then examine under a microscope. (KOH scrapings are commonly used to examine fungal infections.) The

pathognomonic Pathognomonic (rare synonym ''pathognomic'') is a term, often used in medicine, that means "characteristic for a particular disease". A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doub ...

finding is observing

medlar bodies Medlar bodies, also known as sclerotic or muriform cells, are thick walled cells (5-12 microns) with multiple internal transverse septa or chambers that resemble copper pennies. When present in skin or subcutaneous tissue, the cells are indicati ...

(also called muriform bodies or sclerotic cells). Scrapings from the lesion can also be cultured to identify the organism involved. Blood tests and imaging studies are not commonly used.On histology, chromoblastomycosis manifests as pigmented yeasts resembling "copper pennies". Special stains, such as periodic acid schiff and Gömöri methenamine silver, can be used to demonstrate the fungal organisms if needed.

Prevention

No preventive measure is known aside from avoiding the traumatic inoculation of fungi. At least one study found a correlation between walking barefoot in

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

areas and occurrence of chromoblastomycosis on the foot.

Treatment

Chromoblastomycosis is very difficult to cure. The primary treatments of choice are: *

Itraconazole Itraconazole, sometimes abbreviated ITZ, is an antifungal medication used to treat a number of fungal infections. This includes aspergillosis, blastomycosis, coccidioidomycosis, histoplasmosis, and paracoccidioidomycosis. It may be given by mo ...

, an

antifungal An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as ...

azole Azoles are a class of five-membered heterocyclic compounds containing a nitrogen atom and at least one other non-carbon atom (i.e. nitrogen, sulfur, or oxygen) as part of the ring. Their names originate from the Hantzsch–Widman nomenclature. T ...

, is given orally, with or without

flucytosine Flucytosine, also known as 5-fluorocytosine (5-FC), is an antifungal medication. It is specifically used, together with amphotericin B, for serious ''Candida'' infections and cryptococcosis. It may be used by itself or with other antifungals for ...

. * Alternatively,

cryosurgery Cryosurgery is the use of extreme cold in surgery to destroy abnormal or diseased tissue; thus, it is the surgical application of cryoablation. The term comes from the Greek words cryo (κρύο) ("icy cold") and surgery (''cheirourgiki'' – χ� ...

with

liquid nitrogen Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is wid ...

has also been shown to be effective. Other treatment options are the antifungal drug terbinafine, another antifungal azole

posaconazole Posaconazole, sold under the brand name Noxafil among others, is a triazole antifungal medication. It was approved for medical use in the United States in September 2006, and is available as a generic medication. Medical uses Posaconazole is u ...

, and heat therapy.

Antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and preventio ...

may be used to treat bacterial superinfections.

Amphotericin B Amphotericin B is an antifungal medication used for serious fungal infections and leishmaniasis. The fungal infections it is used to treat include mucormycosis, aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, and cryptococcosis ...

has also been used. Photodynamic therapy is a newer type of therapy used to treat Chromblastomycosis.

Prognosis

The prognosis for chromoblastomycosis is very good for small lesions. Severe cases are difficult to cure, although the prognosis is still quite good. The primary complications are ulceration, lymphedema, and secondary bacterial infection. A few cases of

malignant Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

transformation to

squamous cell carcinoma Squamous-cell carcinomas (SCCs), also known as epidermoid carcinomas, comprise a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the ...

have been reported. Chromoblastomycosis is very rarely fatal.

Epidemiology

Chromoblastomycosis occurs around the world, most commonly in rural areas in tropical or subtropical climates. It is most common in rural areas between approximately 30°N and 30°S

latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north ...

. Over two-thirds of patients are

male Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot reproduce sexually without access to ...

, and usually between the ages of 30 and 50. A correlation with HLA-A29 suggests genetic factors may play a role, as well.

Social and cultural

Chromoblastomycosis is considered a

neglected tropical disease Neglected tropical diseases (NTDs) are a diverse group of tropical infections that are common in low-income populations in developing regions of Africa, Asia, and the Americas. They are caused by a variety of pathogens, such as viruses, bac ...

, affects mainly people living in poverty, and causes considerable

morbidity A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

, stigma and discrimination.

References

External links

{{Mycoses Mycosis-related cutaneous conditions Tropical diseases Fungal diseases