Lobo's Disease - Causes, Clinical Features, Diagnosis, and Treatment

Introduction:

Lobomycosis is a self-limited chronic fungal infection of the skin. This is most commonly seen in rural areas of South America and Central America. The natives of the Brazilian forest call this disease miraip or piraip, which means “that which burns.” This disease is caused by fungi called Lacazia loboi, primarily affecting subcutaneous tissue.

What Is Lacazia Loboi?

Lacazia is a genus of fungi. It contains a single species called Lacazia loboi, responsible for Lobo's disease. Lacazia loboi is a yeast-like fungus that causes lobomycosis infection in humans and bottle-nosed dolphins (Tursiops truncatus). The aqueous environment is considered favorable for the lifecycle of Lacazia loboi. Through water, these get transmitted to the vulnerable host via contact. Therefore the infections reported by Lacazia loboi are more commonly from tropical areas.

What Is Lobo’s Disease History?

Lobo's disease is also known as Lobomycosis, Jorge Lobo's disease, keloidal blastomycosis, lacaziosis, and leprosy of the Caiabi's. Jorge Lobo was the first who describe this infection

as keloidal blastomycosis in a patient from the Amazon Valley of Brazil. Later, this disease was found in many patients from South American countries and North American travelers who travel to endemic regions. This disease has also been found in two other species of Atlantic dolphins and one in marine park dolphin trainers. In 1938 this disease was named Lobo disease. In 1958, the name lobomycosis was given, and in 2005, lacaziosis was suggested.

What Is the Epidemiology of Lobo’s Disease?

Most cases of Lobo’s disease have been found in Brazil (64 % cases), and only 1 case of lobomycosis has been reported in the United States. It has been reported that 8.5 % of members of indigenous tribes in South America, such as the Caiabi (Kaiabi) indigenous people of Brazil.

This disease is mostly found in areas higher than 200 meters with humid or tropical forests and an average temperature of 24 degrees Celsius. Therefore this condition has been reported in many areas of Costa Rica, Panama, Venezuela, Colombia, Guyana, Surinam, French Guyana, Ecuador, Peru, Bolivia, Honduras, Italy, Mexico, Holland, the United States, and Canada.

Lobomycosis is more common in men as compared to women. It is mostly found in farmers, rubber workers, and hunters.

What Are the Causes of Lobomycosis?

As mentioned, Lobo’s disease is caused by the fungus Lacazia loboi. This uncultivable dimorphic fungus is mostly found in water, soil, and vegetation. The fungus enters the body accidentally by penetration or trauma. Once it reaches the dermis, it starts multiplying slowly and starts growing. However, it does not spread through human-to-human transmission.

What Are the Clinical Features of Lobo’s Disease?

Lobomycosis is a subcutaneous infection that commonly affects the areas of the body such as the lower and upper limbs, outer ears, face, and thorax. Patients usually have a history of trauma at the site of infection, such as insect or animal bites.

• The lesions can develop after several months of infections and usually starts as a single plaque, papule, or nodule.

• With time, the area of infection expands continuously, along with the development of single or polymorphic plaques or nodules that appear as keloid scars.

• The lesions are smooth, shiny, and intact, and their color can vary from skin color to dark brown. They have well-defined lobulated margins and are not attached to deeper structures.

• Patients may also experience pruritus (itching) or dysesthesia (painful, itching, or burning sensation) in severe cases.

• The lesions may spread from the extremities to the lymph nodes indicating lymphatic spread.

How Is Lobo’s Disease Diagnosed?

The diagnosis is made based on clinical and microscopic examination. Skin biopsy is considered a gold standard for diagnostic confirmation.

• Upon examination, round and oval yeast-like structures with regular size, between 6–12 μm, can be found in the dermis.

• These fungal structures may be present isolated or in Rosario beads formation.

• Direct examination by scraping the lesions is the simplest way to visualize the fungus. Alternatively, vinyl adhesive tape or exfoliative cytology may also be used.

• The formation of fungus is best visualized with silver or periodic acid-Schiff (PAS) stain.

What Is the Treatment for Lobomycosis?

The best treatment option for Lobo’s disease is surgery. Some of the treatment modalities that can be performed to treat this condition include -

1. Surgical Options - Excision with wide margins remains the optimal treatment.

2. Medical Options - Following drugs can be prescribed in this condition, such as -

• Itraconazole (200 to 400 mg/day).
• Clofazimine (100 to 200 mg/day) with a 100 mg/day maintenance dose for two years.
• Posaconazole (only a single case has been reported showing a reduction of lesions after 75 weeks).

3. Physical Modalities -

• Cryosurgery - A procedure in which an extremely cold liquid or an instrument called a cryoprobe is used to freeze and destroy abnormal tissue.
• Electrocauterization - A procedure in which heat is applied from an electric current to destroy abnormal tissue, such as a tumor or other lesion. It may also control bleeding during surgery or after an injury.

New antifungals such as Posaconazole have shown promising results and can cure the lesion without remission in five years of follow-up. However, this lesion has a high recurrence rate, as it can even reoccur if the instrument used in the surgery is contaminated. Therefore, in surgical removal patients, follow-up is necessary to check the reoccurrence of the lesion.

What Are the Complications of Lobomycosis?

Lobo's disease can lead to serious complications if not treated on time, such as in the case of chronic lesions; it can lead to cancerous stages such as squamous cell carcinoma, which can spread very aggressively and recur again after surgical excision. Other than that, some other complications include -

• Disfigurement and deformation of limbs or other body parts lead to functional and esthetic concerns.

• Ulceration.

• Secondary bacterial infections can be managed with systemic and topical antibiotics.

Conclusion:

Lobo’s disease is slow, continuously progressive, and one of the most commonly neglected skin conditions. Without any proper diagnosis and treatment, it can cause some serious damage. This rare disease is only found in the tropical regions of South America. Therefore, it does not impose such a threat. However, it can be a serious condition if not treated on time.