Leishmaniasis

Leishmaniasis is a disease caused by an intracellular protozoan parasite (genus Leishmania) transmitted by the bite of a female phlebotomine sandfly. The clinical spectrum of leishmaniasis ranges from a self-resolving cutaneous ulcer to a mutilating mucocutaneous disease and even to a lethal systemic illness. Therapy has long been a challenge in the more severe forms of the disease, and it is made more difficult by the emergence of drug resistance. With the exception of Australia, the Pacific Islands, and Antarctica, the parasites have been identified throughout large portions of the world.

Signs and symptoms

Cutaneous leishmaniasis includes the following features:

  • Localized cutaneous leishmaniasis: Crusted papules or ulcers on exposed skin; lesions may be associated with sporotrichotic spread

  • Diffuse (disseminated) cutaneous leishmaniasis: Multiple, widespread nontender, nonulcerating cutaneous papules and nodules; analogous to lepromatous leprosy lesions

  • Leishmaniasis recidivans: Presents as a recurrence of lesions at the site of apparently healed disease years after the original infection, typically on the face and often involving the cheek; manifests as an enlarging papule, plaque, or coalescence of papules that heals with central scarring (ie, lesions in the center or periphery of an old healed leishmaniasis scar); relentless expansion at the periphery may cause significant facial destruction similar to the lupus vulgaris variant of cutaneous tuberculosis

  • Post–kala-azar dermal leishmaniasis: Develops months to years after the patient’s recovery from visceral leishmaniasis, with cutaneous lesions ranging from hypopigmented macules to erythematous papules and from nodules to plaques; the lesions may be numerous and persist for decades

Mucocutaneous leishmaniasis consists of the relentless destruction of the oropharynx and nose, resulting in extensive midfacial destruction. Specific signs and symptoms include the following:

  • Excessive tissue obstructing the nares, septal granulation, and perforation; nose cartilage may be involved, giving rise to external changes known as parrot’s beak or camel’s nose

  • Possible presence of granulation, erosion, and ulceration of the palate, uvula, lips, pharynx, and larynx, with sparing of the bony structures; hoarseness may be a sign of laryngeal involvement

  • Gingivitis, periodontitis

  • Localized lymphadenopathy

  • Optical and genital mucosal involvement in severe cases

    Visceral and viscerotropic leishmaniasis include the following features:

    • Visceral leishmaniasis (kala-azar): Potentially lethal widespread systemic disease characterized by darkening of the skin as well as the pentad of fever, weight loss, hepatosplenomegaly, pancytopenia, and hypergammaglobulinemia

    • Viscerotropic leishmaniasis: Nonspecific abdominal tenderness; fever, rigors, fatigue, malaise, nonproductive cough, intermittent diarrhea, headache, arthralgias, myalgias, nausea, adenopathy, transient hepatosplenomegaly

      Diagnosis

      Laboratory diagnosis of leishmaniasis can include the following:

      • Isolation, visualization, and culturing of the parasite from infected tissue

      • Serologic detection of antibodies to recombinant K39 antigen

      • Polymerase chain reaction (PCR) assay for sensitive, rapid diagnosis of Leishmania species

      Other tests that may be considered include the following:

      • CBC count, coagulation studies, liver function tests, peripheral blood smear

      • Measurements of lipase, amylase, gamma globulin, and albumin

      • Leishmanin (Montenegro) skin testing (LST) (not FDA approved in the United States)

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