Leishmaniasis, Cutaneous

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

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)]

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

Medications

OLD WORLD CUTANEOUS LEISHMANIASIS

• Generally self-healing over some months

• Does not metastasize to the mucosa

• May be justified to withhold treatment in regions without mucocutaneous disease if lesions are small and cosmetically unimportant

• Lesions on the face or hands are generally treated

NEW WORLD CUTANEOUS LEISHMANIASIS

• Has a greater risk of progression to mucocutaneous disease, so treatment is more often warranted

• Standard therapy is with pentavalent antimonials for 20 days (see Leishmaniasis, Visceral [Kala Azar])

• Other treatments include

  • Azole antifungals

  • Miltefosine

  • Allopurinol

• Topical therapy has included

  • Intralesional antimony

  • Intralesional pentamidine

  • Paromomycin ointment

  • Cryotherapy

  • Local heat

  • Surgical removal

• Diffuse cutaneous leishmaniasis and related chronic skin processes generally respond poorly to therapy

Prognosis

• For most species, healing occurs spontaneously in months to a few years, but scarring is commonly seen

Prevention

• Avoidance of sand fly bites by

  • Using insect repellants and fine-mesh insect netting

  • Wearing long sleeves and pants

  • Avoiding warm shaded areas where flies are common

• Disease control measures include

  • Destroying animal reservoir hosts

  • Mass treatment of humans in disease-prevalent areas

  • Spraying residual insecticide in dwellings

  • Limiting contact with dogs and other domesticated animals

  • Using permethrin-impregnated collars for dogs