Leishmaniasis is a protozoan, zoonotic parasite spread by sand fly bites. It is endemic in over 80 countries and has an incubation period of 2 to 6 months, although it may range from days to years, with relapse possible. Infection occurs when flagellated forms of more than 20 infective species of Leishmania are injected into the skin, taken up by macrophages, and multiply. Often, the bite goes unnoticed.
The primary cutaneous lesion begins as an enlarging papule, develops a scaly or ulcerative lesion with indurated edges and a central crater, and usually heals spontaneously in 6 to 12 months, but may progress to more diffuse syndromes. Mucocutaneous involvement or “espundia” is mostly seen in Latin America following initial cutaneous infection with Leishmania braziliensis. Nasal congestion and epistaxis may progress to septum perforation and nasal bridge collapse, causing a “tapir nose” deformity. Visceral involvement, known as “kala-azar,” involves the spleen and liver. It is associated with fever, anemia, cachexia, and splenomegaly, and may progress to hemorrhagic symptoms, secondary infections, and GI involvement. Visceral leishmaniasis is generally fatal without treatment.
Coinfection with advanced HIV causes synergistic immunologic disturbances due to the lack of a critical CD+ T-cell response.
The characteristic parasites can be identified from a smear or biopsy of the lesion identifying parasite amastigotes (Leishman-Donovan bodies). Culture and PCR are also diagnostic options.
Cutaneous Leishmaniasis. Lesions in a girl from the highlands of Peru. Most Leishmania lesions are on exposed body areas. (Photo contributors: Rob Greidanus, MD, and Universidad Peruana Cayetano Heredia, Lima, Peru.)
Cutaneous Leishmaniasis. Lesion involving the face of an HIV-infected patient. (Photo contributors: Seth W. Wright, MD, and Universidad Peruana Cayetano Heredia, Lima, Peru.)
Mucocutaneous Leishmaniasis. Mucocutaneous leishmaniasis in a patient from the Andes region of Peru caused by Leishmania peruviana. (Photo contributors: Shannon Langston, MD, and Universidad Peruana Cayetano Heredia, Lima, Peru.)
Management and Disposition
No specific emergency treatment exists for leishmaniasis. Treatment of cutaneous or mucosal disease is with pentavalent antimony, miltefosine, pentamidine, or amphotericin B after referral to an experienced clinician. Protective clothing, bed nets, and insect repellent are the most effective ways of avoiding transmission as the flies are usually active from dusk to dawn. Visceral leishmaniasis should be managed by a tropical medicine or infectious disease specialist as the treatment is difficult and often toxic.
More than 90% of visceral leishmaniasis cases are in India, Bangladesh, Nepal, Sudan, and Brazil, whereas more than 90% of cutaneous forms are in Afghanistan, Algeria, Brazil, Iran, Iraq, Peru, Saudi Arabia, and Syria.