Chromoblastomycosis

What is Chromoblastomycosis?

Chromoblastomycosis is a long-lasting skin infection, caused by specific fungi that have pigment in their cell walls. The infection usually starts when these fungi, including parts of the fungi that can reproduce, enters a person’s skin due to injuries or cuts. The infected area can have various appearances starting as a small pink or red spot, then turning into a bumpy, rough plaque, tumour, or lump, similar to a wart, and could eventually become an ulcer. In later stages, the condition slowly grows into wart-like protrusions that look like a cauliflower.

This condition is most prevalent in tropical and subtropical regions, often overlooked as a typical disease in these areas. Hence, it is important to consider this infection in individuals who have recently travelled or are originally from these regions. To diagnose this condition, doctors look for clusters of pigmented fungal cells, called sclerotic bodies, which are visible in a specific kind of stain or skin biopsy analysis.

While other conditions could also cause wart-like skin changes, chromoblastomycosis is treated primarily through surgical removal if it’s a minor case or with antifungal medication for more severe cases. If not treated, chromoblastomycosis could lead to complications. It could cause extensive tissue damage and swelling, skin cancer in the previously infected area, fluid build-up in extremities, or even further bacterial infection.

What Causes Chromoblastomycosis?

Chromoblastomycosis, a skin condition, can be caused by several types of dark-colored fungi. Most commonly, it’s caused by two specific types: Fonsecaea spp (especially F pedrosoi) and Cladophialophora spp (especially C carrionii).

These dark-colored fungi, also known as demiataceous fungi, can be harmful to humans in two ways. They can either cause chromoblastomycosis or become opportunistic pathogens causing a condition called pheohyphomycosis, which is often linked to issues with internal organs.

Some specific species of these fungi causing chromoblastomycosis include:

• Fonsecaea spp, such as F pedrosoi and F monophora
• Cladophialophora spp, such as C carrionii
• Exophiala spp, such as E dermatitidis and E spinifera
• Phialophora spp, such as P verrucosa and P americana
• Rhinocladiella spp, such as R similis and R mackenziei

These fungi live in the skin, adopting various shapes similar to yeast, and can multiply through asexual reproduction. Some of them have even been seen to reproduce using a special structure called a cleistothecium.

These fungi are common in nature, often found in wood, soil, or other plant materials. Because of this, they are often picked up in rural settings, typically entering the human body through wounds or after exposure to plant materials.

Risk Factors and Frequency for Chromoblastomycosis

Chromoblastomycosis is a disease that’s most common in warm, tropical locations with high humidity. Though it can affect anyone, it’s often found in men aged around 56 who work in agriculture. The disease lasts over 10 years on average, typically causing itchy and painful lesions, or growths, on the lower limbs. The most common types of these growths are verrucous (rough and wart-like) or tumorous (lump-like).

People with this disease often have had a kidney transplant or also have leprosy. The disease, which can lead to disability, is spread through direct contact with soil or plant material and has also been reported in children. However, it’s most prevalent amongst male agricultural workers.

The exact number of people with chromoblastomycosis is hard to determine, as few studies focus on its distribution. Despite this, it’s known as a neglected tropical disease more common in warm climates. It’s less common in areas like the United States and is considered rare in places like India.

The disease is not reported to public health authorities in many countries, so it’s often underestimated. However, the countries where it’s most often reported include South America, Africa, and Asia, especially in Costa Rica, the Dominican Republic, Venezuela, French Guyana, Comoros, Madagascar, and Gabon, among others.

• Chromoblastomycosis is most common in humid, tropical climates.
• It largely affects men around the age of 56, particularly those working in agriculture.
• The disease causes painful, itchy growths on the lower limbs, typically lasting over 10 years.
• Kidney transplant recipients and individuals with leprosy are particularly vulnerable to this disease.
• While it can affect anyone, it’s less common in places like the United States and considered rare in India.
• It’s most frequently reported in countries like Costa Rica, the Dominican Republic, Venezuela, French Guyana, Comoros, Madagascar, and Gabon.

Signs and Symptoms of Chromoblastomycosis

Chromoblastomycosis is a fungal infection that affects the skin, typically in outdoor settings and involves exposure to soil or plant materials. The condition tends to start with a small, reddish spot or bump on the skin, which can progress to different shapes and forms depending on the severity and location of the infection. Common appearances include:

• Warty bumps
• Nodules
• Scaly patches
• Growth or ulcer resembling a cauliflower-like mass
• Scar-like patches

Most often, the lower legs are affected. Nearly all patients with this disease have been exposed to hot, tropical environments. The disease has a slow course, often lasting several weeks before the patient seeks medical help. Because of this, a physical examination should assess the spread of the disease, the presence of any additional lesions, or involvement of deeper organs, which is rare.

If the physical examination reveals signs that point to chromoblastomycosis, the patient’s medical history should be reviewed to rule out other similar conditions. Itchiness is a common complaint among patients with this disease, with pain developing later. However, these symptoms may not become apparent until later stages of the disease, especially in areas of the body that are prone to injury. Important questions relating to the patient’s history may include:

• Recent travel to tropical or subtropical areas
• History of skin changes or previous surgeries in the affected area
• Past skin injuries, such as those from gardening
• Outdoor activities such as hiking or camping
• Work involving outdoor labor, such as farming or other agricultural work
• Skin exposure to the environment, like walking barefoot or exposure to volcanic soil
• History of cancer or infections
• History of inflammatory diseases causing disfiguring skin lesions
• Family history of fungal infections

Even if none of these historical findings are present, chromoblastomycosis cannot be ruled out since patients might not recall having the lesions.

Testing for Chromoblastomycosis

If someone has slow-growing warts, lumps, or scaly patches of skin and has spent time in a tropical or subtropical area, they might have chromoblastomycosis. This skin condition can also occur in people who haven’t been to these geographic areas.

Dermoscopy, a technique involving the examination of the skin with a special magnifying tool, can help the doctor identify tiny black spots on the affected skin. These spots look like specks of cayenne pepper and indicate the presence of hard, globular fungal particles.

Doctors can also take a sample of the skin lesion by scraping it, which is then treated with a special dye called potassium hydroxide. When viewed under a microscope, the dye reveals clusters of fungal cells which look like copper pennies.

However, the surest way to diagnose chromoblastomycosis is by doing a skin biopsy. This involves taking a small sample of the affected skin for examination. Here, doctors look for medlar bodies – thick, round, copper-colored structures in the skin that indicate this particular skin condition. Doctors might have to take two skin samples or divide one sample in two, for better observation. Sometimes, a special fluorescent stain known as calcifluor white is used to make the fungal elements easier to spot under ultraviolet light.

Doctors might also use a fungal culture to determine the type of fungus causing the infection. This process might require using an antibiotic to prevent bacteria from growing in the culture. More specific testing is needed to identify the exact species of fungus responsible for chromoblastomycosis.

While there is no commercial testing available, researchers have used certain blood tests, like enzyme-linked immunosorbent assay (ELISA), to detect antibodies related to this fungal skin infection.

Treatment Options for Chromoblastomycosis

Treatment for Chromoblastomycosis, a skin condition caused by fungus, varies based on how severe the infection is. This can include factors like the size and number of skin lesions, if the patient has any complications, and how well they responded to previous treatments.

If someone has a mild form of the disease, which usually means they have only small nodules or skin patches that are up to 5 cm in diameter, it is usually best treated with a surgical procedure to remove the affected area. This approach can prevent the fungus from spreading. There might also be other treatments used with or without oral medications. These can include light therapy, laser treatments, or heat therapy.

If the patient’s condition is considered moderate to severe, which can mean they have single or multiple large skin patches that can be up to 15 cm in diameter in one or two body areas, antifungal drugs are usually the main course of treatment. Typically, these treatments involve medications called terbinafine and itraconazole.

Sometimes, itraconazole can be used alone for treatment, but usually, it’s taken along with terbinafine or other drugs like 5-fluorocytosine to improve effectiveness. Terbinafine itself can also be used in monotherapy, which means it’s used alone as treatment, but it may not always be successful as a standalone treatment.

Some medications like Posaconazole and Voriconazole are only used for stubborn cases of Chromoblastomycosis or if other medications cannot be used due to cost or other factors. Imiquimod, a type of topical cream, might also be helpful when taken with itraconazole or terbinafine.

Medications like glucan, synthetic retinoids like acitretin, or melanin inhibitors like tricyclazole might be combined with other medications for better results. The choice of medication can also depend on its side-effects, like potential liver damage with terbinafine, or how well they can reach the infected skin area.

Even after the infection has cleared, the doctor may continue to monitor the patient for several months, including regular skin biopsies, to make sure there’s no recurrence of the infection. They will also check for any potential scarring that may result from the disease.

What else can Chromoblastomycosis be?

Chromoblastomycosis, a skin disease, can easily be confused with other conditions that present with similar symptoms. These could include:

• Infectious causes such as:
• Different types of fungal infections like lobomycosis, eumycetoma, and blastomycosis.
• Bacterial infections like tuberculosis, syphilis, or botryomycosis.
• Viral infections such as verruca vulgaris or papilloma.
• Protozoan infections such as leishmaniasis or rhinosporidiosis.
• Helminth infections like filariasis.
• Alga infections like protothecosis.
• Noninfectious causes:
• Skin-related issues like melanoma, keratoacanthoma, or keloid.
• Sarcoidosis, a disease that can affect any organ in the body.
• Podoconiosis, a form of elephantiasis or swelling of the lower limbs.
• Systemic lupus erythematosus, a long-term autoimmune disease in which the body’s immune system becomes hyperactive and attacks normal, healthy tissue.

Remember, it’s crucial for the doctor to consider all these conditions to deliver an accurate diagnosis.

What to expect with Chromoblastomycosis

While it is possible to treat many conditions, some cases may not respond well to treatment. Because of this, it’s crucial to intervene early and maintain regular check-ups to lessen the severity of symptoms and risk of death. Rarely, the disease may affect internal organs, but most frequently, it impacts the skin. Therefore, death due to the disease is less common, except in particular scenarios like widespread disease.

Left untreated, complications are likely to arise. Even with treatment, continuous observation is necessary to watch for negative side effects, such as liver damage.

Possible Complications When Diagnosed with Chromoblastomycosis

The most usual problems that can occur as a result of chromoblastomycosis include scarring (particularly atrophic scarring, which is a type of scar that sinks below the level of the skin), tissue that becomes fibrous and prevents movement (which could, for example, cause ectropion, a condition where the eyelid turns outward, or affect joint mobility), skin ulcers, additional bacterial infection, lymphatic spread in a sporotrichoid pattern (a rare skin infection caused by a mold), and lymphedema, which results in a condition called elephantiasis that causes severe swelling.

In uncommon cases, chromoblastomycosis can turn into a type of skin cancer known as squamous cell carcinoma and can even spread throughout the body, though this rarely happens as compared to other similar fungi.

Side Effects:

• Scarring (especially atrophic scarring)
• Disabling tissue fibrosis (leading to ectropion or joint immobility)
• Skin ulcers
• Additional bacterial infection
• Lymphatic spread in a sporotrichoid pattern
• Lymphedema causing elephantiasis
• Malignant transformation to squamous cell carcinoma (rare)
• Dissemination of disease (rare)

Preventing Chromoblastomycosis

People should be thoroughly educated about how to prevent chromoblastomycosis, a skin disease often found in certain regions. To avoid the disease, it’s essential to avoid skin injuries, especially when in places where the disease is common. Wearing protective gear is recommended for those who spend a lot of time outdoors, whether for work or recreation. However, please note that many people who are at risk for this disease live in hot, low-resource settings, which means the use of protection measures should be realistic and well-thought-out.

Currently, there are no commercial vaccines for chromoblastomycosis due to limited studies conducted. This makes prevention all the more vital.

During treatment, patients should be taught about the expected course of treatment. It may take a long time and require multiple sessions, so patience and consistency in keeping up with the treatment are crucial. It’s also important for patients to have a good understanding of the potential side effects of the medications they will be taking, and they should be aware of any possible interactions between these medications and other drugs they may be using.