Skin-nontumor / Clinical dermatology
Infectious disorders
Leishmaniasis

Author: Mowafak Hamodat, MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 31 May 2016, last major update July 2011

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Leishmaniasis infection [title]

Cite this page: Leishmaniasis. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skinnontumorleishmaniasis.html. Accessed December 8th, 2016.
Clinical Features
  • Protozoal disease in all continents except Australia and Antarctica
  • 1 - 2 million new cases per year worldwide
  • Epidemics occur periodically in tropical regions of world; also infections in HIV+ patients
  • Produces crusted, indurated papule that slowly enlarges and is self limited, as well as fatal systemic illness
  • Disease is either cutaneous, mucocutaneous or visceral
  • May may be misinterpreted as sarcoidosis, foreign body reaction, granulomatous rosacea and even granuloma annulare

  • Cutaneous: usually restricted to face, scalp, arms or other exposed areas
  • Localized, disseminated (if immune system doesnt respond to invading parasites), recurrent (recidivans cutaneous) or post-kala azar (rare, years after visceral disease)

  • Mucocutaneous: usually New World disease of rural and jungle regions
  • Occurs when primary infection with L. braziliensis becomes disseminated to upper respiratory tract, produces lesions of oral, pharyngeal or nasal mucosa with ulceration, mutilation or sometimes death

  • Visceral: also called kala azar; parasites throughout reticuloendothelial system, causing fever, malaise, hepatosplenomegaly, anorexia, pancytopenia, hypergammaglobulinemia
  • Usually spares skin except for irregular areas of dark pigmentation (kala azar means black sickness)
  • May cause death if untreated
  • Broadly divided into old world (tropical and subtropical Asia, India, Africa and Mediterranean) and new world (Americas)
  • Old world: usually Leishmania tropica complex
  • New world: L. braziliensis complex and L. mexicana complex
  • L. braziliensis may also produce espundia, a destructive mucocutaneous form
  • Human infection through bite of Phlebotomus sand fly (smaller than mosquitoes); rarely through blood contamination
  • Clinical presentation and prognosis vary based on species, duration of infection and immune status of patient
  • US infections primarily through travel and HIV infection

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    Life cycle

Diagnosis
  • Intradermal delayed hypersensitivity test (Montenegro); culture on NNN agar using smears from ulcer; also ELISA, DNA probes, PCR
  • Also by identifying parasites on H&E or in smears, by culture on specialized media, by leishmanin intradermal skin test (Montenegro test), by fluorescent antibody tests using the patient's serum, or by PCR using species-specific primers (but PCR results can be false positive)

  • Note: leishmanin test is usually negative in the forms with cell-mediated hyporeactivity, such as the diffuse cutaneous forms and the visceral form (kala-azar)
Treatment
Clinical Images

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Cutaneous and mucosal forms

Micro Description
  • Dermal granulomatous inflammation with prominent lymphocytes
  • Histiocytes contain small oval organisms with bar shaped paranuclear kinetoplast
Micro Images

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Various images contributed by Professor Venna Maheshwar, Drs. Kiran Alam and Anshu Jain



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Various images



Bone marrow aspirate smear of visceral leishmaniasis

Positive Stains
  • Weigert iron hematoxylin may stain parasites better than H&E or Giemsa
  • Immunohistostain using G2D10 antibody is more sensitive than H&E