B48.0 Lobomycosis

Name of the Condition

• Lobomycosis

Summary

Lobomycosis is a chronic fungal infection of the skin and subcutaneous tissues caused by Lacazia loboi. It is characterized by the formation of nodular or keloidal lesions, typically on exposed areas such as the extremities, face, or ears. The condition progresses slowly and may persist for years without treatment, with a predilection for tropical and subtropical regions.

Causes

The infection is caused by Lacazia loboi, a dimorphic fungus found in soil and vegetation. Transmission is thought to occur through direct inoculation of the skin, often via minor trauma or insect bites, in endemic areas. The fungus is not known to spread person-to-person or through respiratory routes.

Risk Factors

• Residence or travel to endemic regions (e.g., South America, Central America, or parts of Africa).
• Prolonged outdoor exposure in tropical environments.
• Skin trauma or breaks that may facilitate fungal entry.
• Occupational or recreational activities involving contact with soil or vegetation.

Symptoms

• Slow-growing, painless nodules or plaques on the skin.
• Lesions may be firm, raised, and have a smooth or warty surface.
• Commonly affects exposed areas like the arms, legs, face, or ears.
• Lesions may ulcerate or become secondarily infected in advanced cases.

Diagnosis

Diagnosis is confirmed by histopathological examination of tissue samples, which reveals characteristic yeast-like cells (Loboa loboi) within granulomas. Culture of the fungus is challenging due to its fastidious nature, so microscopic identification is primary. Imaging may be used to assess deeper tissue involvement.

Treatment Options

• Surgical excision of localized lesions, often the first-line approach.
• Cryotherapy or laser therapy for smaller or superficial lesions.
• Antifungal medications (e.g., itraconazole) may be used for extensive disease, though efficacy varies.
• Long-term monitoring is recommended due to the risk of recurrence.

Prognosis and Follow-Up

Prognosis is generally good with complete surgical removal, but recurrence is possible. Untreated lesions may persist for decades or progress to disfigurement. Follow-up includes regular skin examinations to monitor for regrowth or new lesions, especially in endemic areas.

Complications

• Disfigurement or functional impairment from large or extensive lesions.
• Secondary bacterial infection of ulcerated lesions.
• Psychological impact due to cosmetic changes.
• Rarely, extension to deeper tissues or bones in severe cases.

Lifestyle & Prevention

• Avoid skin trauma in endemic regions.
• Use protective clothing (e.g., long sleeves, pants) when working outdoors.
• Promptly clean and treat minor skin injuries to reduce infection risk.
• Seek early evaluation for persistent skin lesions in high-risk areas.

When to Seek Professional Help

• New, persistent, or growing skin nodules, especially after travel to endemic regions.
• Lesions that ulcerate, become painful, or show signs of infection.
• Concerns about cosmetic or functional impact of skin changes.

Tips for Medical Coders

• Code B48.0 is specific to lobomycosis and should be used when the condition is documented.
• Ensure documentation supports the diagnosis, including clinical presentation and any histopathological confirmation.
• Differentiate from other fungal infections (e.g., mycetoma or sporotrichosis) to avoid miscoding.
• Note that this code is for the condition itself, not for complications or associated procedures.