Lobomycosis, also known as Jorge Lobo disease, lacaziosis, or keloidal blastomycosis, is a chronic cutaneous and subcutaneous fungal disease endemic to tropical and subtropical regions of Central and South America. The organism, Lacazia loboi (previously Loboa loboi), is an uncultivable Onygenale fungus found in soil, vegetation, and freshwater habitats, and, to date, cannot be cultured in vitro.

The onset of lobomycosis is insidious and progresses over decades. The incubation period is months to years. The fungus grows at temperatures lower than 37°C (98.6°F), and as a result, systemic spread of the infection does not occur. There is often a history of antecedent trauma and subsequent environmental exposure (often water).

There is a strong male predominance (approximately 90% of cases), occurring mostly between the ages of 40 and 70 years, likely related to occupational exposure (eg, agriculture).

There may be genetic factors increasing the risk of infection as certain American Indian tribes of Brazil are frequently infected; however, specific genetic markers have not been identified. This disease is very rare in travelers, and the first case in an American traveler was reported in 2000.

Dolphins are described as the primary nonhuman host for lobomycosis. While lobomycosis is classically described in human populations in the Amazon region, affected dolphin populations have been identified in the Atlantic, Pacific, and Indian Oceans. Intriguingly, epidemiologic evidence for transmission from dolphins to humans is weak and recent taxonomic studies suggest the causative organisms in the 2 species may in fact be different.

The skin lesions resemble keloids or may be verrucous or vegetating. They grow slowly, and symptoms are often mild, such as mild pruritus or pain with trauma to the lesions. Therefore, there is often a delay in making the diagnosis. Malignant transformation to squamous cell carcinoma is possible but rare.