Leishmaniasis, Cutaneous

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 600,000 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

• Hansen disease (leprosy)

• Fungal infection

• Cutaneous tuberculosis

• Neoplasm

• Syphilis, yaws

• Sarcoidosis

• L donovani [see Leishmaniasis, Visceral (Kala Azar)]

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 ...