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For further information, see CMDT Part 35-03: Leishmaniasis

Key Features

Essentials of Diagnosis

  • Sand fly bite in an endemic area

  • Chronic, painless, moist ulcers or dry nodules

  • Amastigotes in macrophages in aspirates, touch preparations, or biopsies

  • Positive culture, serologic tests, polymerase chain reaction, or skin test

General Considerations

  • Transmitted by bites of sand flies of the genus Lutzomyia in the Americas and Phlebotomus elsewhere

  • Caused by about 20 species of Leishmania; taxonomy is complex

  • When sand flies feed on an infected host, the parasitized cells are ingested with the blood meal

  • Clinical syndromes are generally dictated by the infecting species, but some species can cause more than one syndrome

  • Old World cutaneous leishmaniasis is caused mainly by Leishmania tropica, Leishmania major, and Leishmania aethiopica in the Mediterranean, Middle East, Africa, Central Asia, and Indian subcontinent

  • New World cutaneous leishmaniasis is caused by Leishmania mexicana and Leishmania amazonensis in Central and South America

Demographics

  • The estimated annual incidence of disease has been decreasing; current estimate is 700,000 to 1 million annual cases

  • About 90% of cases of cutaneous leishmaniasis occur in

    • Afghanistan

    • Pakistan

    • Syria

    • Saudi Arabia

    • Algeria

    • Iran

    • Brazil

    • Peru

Clinical Findings

Symptoms and Signs

  • Cutaneous swellings appears 1 weeks to several months after sand fly bites and can be single or multiple

  • Characteristics of lesions and courses of disease vary depending on the leishmanial species and host immune response

  • Lesions begin as small papules and develop into

    • Nonulcerated dry plaques

    • Large encrusted ulcers with well-demarcated raised and indurated margins

  • Satellite lesions may be present

  • The lesions are painless unless secondarily infected

  • Local lymph nodes may be enlarged

  • Systemic symptoms are uncommon, but fever, constitutional symptoms, and regional lymphadenopathy may be seen

  • Leishmaniasis recidivans is a relapsing form of L tropica infection associated with hypersensitivity, in which the primary lesion heals centrally, but spreads laterally, with extensive scarring

  • Diffuse cutaneous leishmaniasis

    • Involves spread from a primary lesion with local dissemination of nodules and a protracted course

    • Involves multiple nodular or ulcerated lesions, often with mucosal involvement

Differential Diagnosis

Diagnosis

Laboratory Tests

  • Identifying amastigotes within macrophages in tissue samples provides a definitive diagnosis

  • Biopsy specimens should be taken from raised border of skin lesion, with samples for histopathology, touch preparation, and culture

  • Histopathology shows inflammation with mononuclear cells

  • Macrophages filled with amastigotes may be present, especially early in infection

  • Intradermal leishmanin (Montenegro) skin test

    • Positive in most individuals with cutaneous disease but negative in those with progressive visceral or diffuse cutaneous disease

    • This test is not approved in the United States

Treatment

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