Balamuthia infection is a rare but deadly protozoan infection affecting primarily the skin and the central nervous system, caused by the free-living amoeba Balamuthia mandrillaris, which lives in soil, dust, and water. The infection is acquired through skin inoculation or inhalation and presents as a thin, painless, skin-colored to violaceous papule or plaque, usually on the central face. Other common locations include the knees, elbows, or chest. The infection should be treated aggressively, as most patients with the cutaneous infection follow a fatal course from the development of granulomatous amoebic encephalitis (GAE). GAE is a slowly progressive and life-threatening disease with multifocal, hemorrhagic, and necrotizing encephalitis. Ocular and upper and lower respiratory tract involvement may be observed. Cutaneous, ocular, and pulmonary lesions can precede neurological involvement by months to years.

Balamuthia infection is more common in North and South America and typically affects children and, in the United States, adult males of Hispanic descent. Balamuthia can affect both immunocompromised and immunocompetent hosts. Of note, transmission through organ transplantation has been reported with an incubation period of 17-24 days. A history of swimming in lakes, ponds, and swimming pools may be elicited.