Diagnostic Considerations
As noted earlier, infection with different Leishmania species can lead to a remarkably broad range of disease states. The clinical spectrum can range from insignificant pustules to fatal systemic disease. General understanding of this clinical spectrum, although once believed to be quite predictable, continues to evolve as new diagnostic techniques contribute to the elucidation of the variety of clinical manifestations of an infection with even a single species of Leishmania.
Coexisting infectious diseases and/or nutritional deficiencies may significantly impact the severity and outcome of leishmanial infection. In southern Europe along the Mediterranean, visceral leishmaniasis is emerging most notably as a serious opportunistic infection in individuals with human immunodeficiency virus (HIV) infection, where most adult patients (< 70%) with visceral leishmaniasis have late-stage acquired immunodeficiency syndrome (AIDS). Individuals with HIV infection and leishmaniasis have higher parasite loads, poorer responses to skin testing, lower responses to pentavalent antimony, and higher posttreatment relapse rates than those of their immunocompetent counterparts. [15]
Cutaneous leishmaniasis
Localized cutaneous leishmaniasis usually manifests as a nonspecific ulcer that can mimic many other infectious and noninfectious skin conditions. The vast majority of cases patients spontaneously with scarring and never come to the attention of clinicians. Even in US troops stationed in Iraq, it has been felt, by many most closely associated with the disease and familiar with the epidemiology in the military, that less than 25% of all disease ever concerns afflicted soldiers enough to seek medical attention.
Other conditions to consider in the differential diagnosis for leishmaniasis include the following:
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Fungal: Chromoblastomycosis, lobomycosis, deep fungal infection
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Bacterial: Cutaneous diphtheria, rhinoscleroma ,tropical pyoderma, and other mycobacterioses (eg, Mycobacterium avium-intracellulare, Mycobacterium marinum infection of the skin)
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Viral: Orf
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Inflammatory diseases: Pyogenic granuloma, nummular dermatitis, plaque psoriasis
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Malignant neoplasms: Metastases, psoriasis, keloids
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Ulcers: Traumatic ulcers, stasis ulcers
Mucocutaneous leishmaniasis
Other conditions to consider in the differential diagnosis for mucocutaneous leishmaniasis include the following:
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Polymorphic reticulosis
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Wegener granulomatosis
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Lymphoma (eg, angiocentric NK/T-cell lymphoma)
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Nasopharyngeal carcinoma
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Lethal midline granuloma
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Other destructive lesions
Visceral leishmaniasis
Visceral leishmaniasis may be confused with a variety of other infectious diseases or febrile systemic illnesses. In endemic areas, the diagnosis of visceral leishmaniasis is often made based on the history and physical examination.
Other conditions to consider in the differential diagnosis for visceral leishmaniasis include the following:
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Brucellosis
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Schistosomiasis
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Leukemia (eg, acute lymphoblastic leukemia, acute myelogenous leukemia) and lymphoma (chronic lymphocytic leukemia, chronic myelogenous leukemia)
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Portal hypertension
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Malnutrition
Differential Diagnoses
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Lymphoma, Cutaneous T-Cell
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Physical Medicine and Rehabilitation for Systemic Lupus Erythematosus
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Pyoderma Gangrenosum
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Squamous Cell Carcinoma
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Yaws
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Classic Leishmania major lesion from a case in Iraq shows a volcanic appearance with rolled edges.
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Atypical appearance of Leishmania major lesion with local spread beyond the borders of the primary lesion. Many of the lesions in cases from Iraq show an atypical appearance.
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Old World localized cutaneous leishmaniasis located on the trunk of a soldier stationed in Kuwait. This lesion was a 3-cm by 4-cm nontender ulceration that developed over the course of 6 months at the site of a sandfly bite. The patient reported seeing several rats around his encampment.
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Old World cutaneous leishmaniasis located on the right arm of the same soldier stationed in Kuwait. This 2-cm by 3-cm lesion was located at the exposed area where the sleeve ended. Note the satellite lesions.
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Active cutaneous leishmaniasis lesion with likely secondary infection in a soldier.
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Cutaneous leishmaniasis with keloid formation in a black soldier.
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Taxonomy of some of the medically important protozoans showing the relative relationship of the Kinetoplastida parasites generally, and Leishmania specifically.
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Leishmania donovani is one of the main Leishmania species that infects humans.
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Life cycles of the medically important Kinetoplastida illustrating the similarities and differences between the trypanosomes and Leishmania.
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Distribution map of cutaneous leishmaniasis.
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Geographical distribution of Old World cutaneous leishmaniasis due to L tropica and related species and L aethiopica. Source: World Health Organization, Department of Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management (WHO/NTD/IDM) Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS), Tuberculosis and Malaria (HTM) WHO, October 2010: http://www.who.int/leishmaniasis/leishmaniasis_maps/en/index1.html
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Geographical distribution of Old World cutaneous leishmaniasis due to L major. Source: World Health Organization, Department of Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management (WHO/NTD/IDM) Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS), Tuberculosis and Malaria (HTM) WHO, October 2010: http://www.who.int/leishmaniasis/leishmaniasis_maps/en/index1.html.
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Geographical distribution of cutaneous and mucocutaneous leishmaniasis in the New World. Source: World Health Organization, Department of Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management (WHO/NTD/IDM) Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS), Tuberculosis and Malaria (HTM) WHO, October 2010: http://www.who.int/leishmaniasis/leishmaniasis_maps/en/
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Geographical distribution of visceral leishmaniasis in the Old and New world. Source: World Health Organization, Department of Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management (WHO/NTD/IDM) Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS), Tuberculosis and Malaria (HTM) WHO, October 2010: http://www.who.int/leishmaniasis/leishmaniasis_maps/en/.
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Distribution map of visceral leishmaniasis.
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Distribution map of human immunodeficiency virus (HIV) and leishmaniasis coinfection.
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The predominant mode of leishmaniasis transmission is a sandfly's bite.
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Sandfly. Courtesy of Kenneth F. Wagner, MD.
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Comparison of a sandfly (left) and a mosquito (right). The sandfly's small size affects the efficacy of bed nets when used without permethrin treatment.
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Cutaneous leishmaniasis. Courtesy of Kenneth F. Wagner, MD.
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Cutaneous leishmaniasis lesion. Image courtesy of the Centers for Disease Control and Prevention Public Health Image Library.
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Cutaneous leishmaniasis with sporotrichotic spread.
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Cutaneous leishmaniasis lesion. Image courtesy of the Centers for Disease Control and Prevention Public Health Image Library.
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Cutaneous leishmaniasis is generally considered to be an innocuous disease; however, in some parts of the world, especially in tribal areas, even cutaneous disease can have a life altering effect on a person's life. Minimal facial disfiguring can condemn young girls to life without the prospect of marriage or acceptance in society.
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Leishmaniasis in an Ethiopian woman with a 1-year history of asymptomatic pink-erythematous infiltrative plaque with overlying scale and central crust.
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Healed cutaneous leishmaniasis lesions. Photo courtesy of Robert Norris, MD, Stanford University Medical Center.
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Cutaneous leishmaniasis lesions. Photo courtesy of Robert Norris, MD, Stanford University Medical Center.
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Diffuse (disseminated) cutaneous leishmaniasis. Courtesy of Jacinto Convit, National Institute of Dermatology in Caracas, Venezuela.
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Leishmaniasis recidivans. Courtesy of Kenneth F. Wagner, MD.
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Post–kala-azar dermal leishmaniasis. Courtesy of R. E. Kuntz and R. H. Watten, Naval Medical Research Unit, Taipei, Taiwan.
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Mucocutaneous leishmaniasis. Courtesy of Kenneth F. Wagner, MD.
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Mucocutaneous leishmaniasis. Courtesy of Kenneth F. Wagner, MD.
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Visceral leishmaniasis. Courtesy of Kenneth F. Wagner, MD.
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Marked splenomegaly (enlargement/swelling of the spleen) in a patient in lowland Nepal who has visceral leishmaniasis. (Credit: C. Bern, CDC) Source: Centers for Disease Control and Prevention. Parasites home: leishmaniasis. Resources for health professionals: http://www.cdc.gov/parasites/leishmaniasis/health_professionals/.
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Amastigotes in a macrophage at 1000× magnification. Inset shows the cell membrane and points out the nucleus and kinetoplast, which are required to confirm that the inclusion seen in a macrophage is indeed an amastigote.
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Free amastigotes near a disrupted macrophage. On touch preparations like this (Giemsa stain, original magnification × 1000), the amastigotes are easier to identify than on other preparations. These stains clearly demonstrate the cell membrane, nucleus, and kinetoplast; all 3 are required for definitive diagnosis.
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Free amastigote in a touch preparation (Giemsa stain, original magnification × 1000).
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Light-microscopic examination of a stained bone marrow specimen from a patient with visceral leishmaniasis—showing a macrophage (a special type of white blood cell) containing multiple Leishmania amastigotes (the tissue stage of the parasite). Note that each amastigote has a nucleus (red arrow) and a rod-shaped kinetoplast (black arrow). Visualization of the kinetoplast is important for diagnostic purposes, to be confident the patient has leishmaniasis. (Credit: CDC/DPDx) Source: Centers for Disease Control and Prevention. Parasites home: leishmaniasis. Resources for health professionals: http://www.cdc.gov/parasites/leishmaniasis/health_professionals/
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Illustration of one form of the rK39 test for the serologic diagnosis of visceral leishmaniasis. It is an easy, very sensitive, and specific test for visceral disease. In this case, the dipstick second from the left shows a positive result and all the rest show reaction only at the control line.
