Chromoblastomycosis | |
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Other names | Chromomycosis, [1] Cladosporiosis, [1] Fonseca's disease, [1] Pedroso's disease, [1] Phaeosporotrichosis, [1] or Verrucous dermatitis [1] |
Micrograph of chromoblastomycosis showing sclerotic bodies | |
Specialty | Infectious disease, Dermatology |
Chromoblastomycosis is a long-term fungal infection of the skin [2] and subcutaneous tissue (a chronic subcutaneous mycosis). [3]
It can be caused by many different types of fungi which become implanted under the skin, often by thorns or splinters. [4] Chromoblastomycosis spreads very slowly.[ citation needed ]
It is rarely fatal and usually has a good prognosis, but it can be very difficult to cure. The several treatment options include medication and surgery. [5]
The infection occurs most commonly in tropical or subtropical climates, often in rural areas. [6]
The initial trauma causing the infection is often forgotten or not noticed. The infection builds at the site over the years, and a small red papule (skin elevation) appears. The lesion is usually not painful, with few, if any symptoms. Patients rarely seek medical care at this point.[ citation needed ]
Several complications may occur. Usually, the infection slowly spreads to the surrounding tissue while remaining localized to the area around the original wound. However, sometimes the fungi may spread through the blood vessels or lymph vessels, producing metastatic lesions at distant sites. Another possibility is secondary infection with bacteria. This may lead to lymph stasis (obstruction of the lymph vessels) and elephantiasis. The nodules may become ulcerated, or multiple nodules may grow and coalesce, affecting a large area of a limb.[ citation needed ]
Chromoblastomycosis is believed to originate in minor trauma to the skin, usually from vegetative material such as thorns or splinters; this trauma implants fungus 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:
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.[ citation needed ]
The most informative test is to scrape the lesion and add potassium hydroxide (KOH), then examine it under a microscope. (KOH scrapings are commonly used to examine fungal infections.) The pathognomonic finding is observing medlar bodies (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.[ citation needed ]
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 areas and the occurrence of chromoblastomycosis on the foot.[ citation needed ]
Chromoblastomycosis is very difficult to cure. The primary treatments of choice are:[ citation needed ]
Other treatment options are the antifungal drug terbinafine, [12] another antifungal azole posaconazole, and heat therapy.
Antibiotics may be used to treat bacterial superinfections.[ citation needed ]
Amphotericin B has also been used. [13]
Photodynamic therapy is a newer type of therapy used to treat Chromoblastomycosis. [14]
The prognosis for chromoblastomycosis is very good for small lesions. Severe cases are difficult to cure, although the prognosis is still good. The primary complications are ulceration, lymphedema, and secondary bacterial infection. A few cases of malignant transformation to squamous cell carcinoma have been reported. Chromoblastomycosis is very rarely fatal.[ citation needed ]
Chromoblastomycosis occurs globally, most commonly in rural areas in tropical or subtropical climates. [6]
It is most common in rural areas between approximately 30°N and 30°S latitude. Over two-thirds of patients are male, usually between the ages of 30 and 50. A correlation with HLA-A29 suggests genetic factors may play a role, as well. [15]
Chromoblastomycosis is considered a neglected tropical disease, affects mainly people living in poverty, and causes considerable morbidity, stigma, and discrimination. [6]
Tinea corporis is a fungal infection of the body, similar to other forms of tinea. Specifically, it is a type of dermatophytosis that appears on the arms and legs, especially on glabrous skin; however, it may occur on any superficial part of the body.
Fungal infection, also known as mycosis, is a 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 tinea of the skin, such as tinea of the body, groin, hands, feet and beard, and yeast infections such as pityriasis versicolor. Subcutaneous types include eumycetoma and chromoblastomycosis, which generally affect tissues in and beneath the skin. Systemic fungal infections are more serious and include cryptococcosis, histoplasmosis, pneumocystis pneumonia, aspergillosis and mucormycosis. Signs and symptoms range widely. There is usually a rash with superficial infection. Fungal infection within the skin or under the skin may present with a lump and skin changes. Pneumonia-like symptoms or meningitis may occur with a deeper or systemic infection.
Eumycetoma, also known as Madura foot, is a persistent fungal infection of the skin and the tissues just under the skin, affecting most commonly the feet, although it can occur in hands and other body parts. It starts as a painless wet nodule, which may be present for years before ulceration, swelling, grainy discharge and weeping from sinuses and fistulae, followed by bone deformity.
Sporotrichosis, also known as rose handler's disease, is a fungal infection that may be localised to skin, lungs, bone and joint, or become systemic. It presents with firm painless nodules that later ulcerate. Following initial exposure to Sporothrix schenckii, the disease typically progresses over a period of a week to several months. Serious complications may develop in people who have a weakened immune system.
Phycomycosis is an uncommon condition affecting the gastrointestinal tract and skin, most commonly found in dogs and horses. The condition is caused by various molds, with individual forms including pythiosis, zygomycosis, and lagenidiosis. Pythiosis, the most common type, is caused by Pythium, a type of water mould. Zygomycosis can be caused by two types of zygomycetes: Entomophthorales and Mucorales. The latter type of zygomycosis is also referred to as mucormycosis. Lagenidiosis is caused by a Lagenidium species, which like Pythium is a water mould. Since both pythiosis and lagenidiosis are caused by organisms from the Oomycetes and not the kingdom fungi, they are sometimes collectively referred to as oomycosis.
Talaromycosis is a fungal infection that presents with painless skin lesions of the face and neck, as well as an associated fever, anaemia, and enlargement of the lymph glands and liver.
Bacillary angiomatosis (BA) is a form of angiomatosis associated with bacteria of the genus Bartonella.
Basidiobolomycosis is a fungal disease caused by Basidiobolus ranarum. It may appear as one or more painless firm nodules in the skin which becomes purplish with an edge that appears to be slowly growing outwards. A serious but less common type affects the stomach and intestine, which usually presents with abdominal pain, fever and a mass.
Exophiala jeanselmei is a saprotrophic fungus in the family Herpotrichiellaceae. Four varieties have been discovered: Exophiala jeanselmei var. heteromorpha, E. jeanselmei var. lecanii-corni, E. jeanselmei var. jeanselmei, and E. jeanselmei var. castellanii. Other species in the genus Exophiala such as E. dermatitidis and E. spinifera have been reported to have similar annellidic conidiogenesis and may therefore be difficult to differentiate.
Geotrichosis is a mycosis caused by Geotrichum candidum.
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 as a soil saprotroph. Farming activities in the endemic zone are a risk factor for the development of chromoblastomycosis.
Majocchi's granuloma is a skin condition characterized by deep, pustular plaques, and is a form of tinea corporis. It is a localized form of fungal folliculitis. Lesions often have a pink and scaly central component with pustules or folliculocentric papules at the periphery. The name comes from Domenico Majocchi, who discovered the disorder in 1883. Majocchi was a professor of dermatology at the University of Parma and later the University of Bologna. This disease is most commonly caused by filamentous fungi in the genus Trichophyton.
Exophiala dermatitidis is a thermophilic black yeast, and a member of the Herpotrichiellaceae. While the species is only found at low abundance in nature, metabolically active strains are commonly isolated in saunas, steam baths, and dish washers. Exophiala dermatitidis only rarely causes infection in humans, however cases have been reported around the world. In East Asia, the species has caused lethal brain infections in young and otherwise healthy individuals. The fungus has been known to cause cutaneous and subcutaneous phaeohyphomycosis, and as a lung colonist in people with cystic fibrosis in Europe. In 2002, an outbreak of systemic E. dermatitidis infection occurred in women who had received contaminated steroid injections at North Carolina hospitals.
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 with an array of melanistic filamentous fungi including Alternaria species, Exophiala jeanselmei, and Rhinocladiella mackenziei.
Phialemonium curvatum is a pathogenic fungus in the phylum Ascomycota. The genus was created to accommodate taxa intermediate to Acremonium and Phialophora. This genus is characterized by its abundance of adelophialides and few discrete phialides with no signs of collarettes. Specifically, P. curvatum is characterized by its grayish white colonies and its allantoid conidia. Phialemonium curvatum is typically found in a variety of environments including air, soil, industrial water and sewage. Furthermore, P. curvatum affects mainly immunocompromised and is rarely seen in immunocompetent people. The species has been known to cause peritonitis, endocarditis, endovascular infections, osteomyelitis as well as cutaneous infections of wounds and burns.
Histoplasma duboisii is a saprotrophic fungus responsible for the invasive infection known as African histoplasmosis. This species is a close relative of Histoplasma capsulatum, the agent of classical histoplasmosis, and the two occur in similar habitats. Histoplasma duboisii is restricted to continental Africa and Madagascar, although scattered reports have arisen from other places usually in individuals with an African travel history. Like, H. capsulatum, H. duboisii is dimorphic – growing as a filamentous fungus at ambient temperature and a yeast at body temperature. It differs morphologically from H. capsulatum by the typical production of a large-celled yeast form. Both agents cause similar forms of disease, although H. duboisii predominantly causes cutaneous and subcutaneous disease in humans and non-human primates. The agent responds to many antifungal drug therapies used to treat serious fungal diseases.
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. compacta are glycolipids, yet very little is known about its composition. F. compacta is widely regarded as a dysplastic variety of Fonsecaea pedrosoi, its morphological precursor. The genus Fonsecaea presently contains two species, F. pedrosoi and F. compacta. Over 100 strains of F. pedrosoi have been isolated but only two of F. compacta.
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 disease. Cladophialophora carrionii is a causative agent of chromoblastomycosis, a subcutaneous infection that occurs in sub-tropical areas such as Madagascar, Australia and northwestern Venezuela. Transmission occurs through traumatic implantation of plant material colonized by C. carrionii, mainly infecting rural workers. When C. carrionii infects its host, it transforms from a mycelial state to a muriform state to better tolerate the extreme conditions in the host's body.
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 be found in rotting wood, soil, wasp nests, and plant debris. P. verrucosa is sometimes referred to as Phialophora americana, a closely related environmental species which, along with P. verrucosa, is also categorized in the P. carrionii clade.
Cladophialophora arxii is a black yeast shaped dematiaceous fungus that is able to cause serious phaeohyphomycotic infections. C. arxii was first discovered in 1995 in Germany from a 22-year-old female patient suffering multiple granulomatous tracheal tumours. It is a clinical strain that is typically found in humans and is also capable of acting as an opportunistic fungus of other vertebrates Human cases caused by C. arxii have been reported from all parts of the world such as Germany and Australia.