Leishmaniasis

Author: Vanessa Ngan, Staff Writer, 2005. Updated by Dr Catriona Wootton, Dermatologist, UK, January 2017.


What is leishmaniasis?

Leishmaniasis is a parasitic disease transmitted by sandflies infected with the protozoa Leishmania. Leishmaniasis is endemic in more than 70 countries worldwide and affects an estimated 12 million people.

There are several clinical forms of leishmaniasis. The clinical manifestation of the infection depends on the species of Leishmania, which varies with geographical area and the host’s immune response.

Parasites causing human leishmaniasis are not found in New Zealand, Australia, the South Pacific or Antarctica. 

Who gets leishmaniasis?

People of all ages, living or travelling through areas where sandflies and Leishmania species are endemic are at risk of infection with leishmaniasis. Living in rural areas and spending time on or near the ground increases the risk.

Classification and causes of leishmaniasis

There are more than 20 species of Leishmania parasites which can infect humans; transmitted via the bite of phlebotomine sandflies. Sandflies are tiny (1.5–3 mm) insects which actively feed on blood at dawn and dusk. Sandflies live in wall cracks, animal burrows and leaf litter, in tropical and sub-tropical regions. Their bite is asymptomatic and classically on exposed sites.

Leishmaniasis has several recognized clinical forms and their manifestation depends upon the species inoculated and the host’s immune response. The most important distinction is between American and non-American species of Leishmania, as the Viannia subspecies found in the Americas, can result in mucocutaneous leishmaniasis. 

Cutaneous leishmaniasis

Cutaneous leishmaniasis typically occurs at the site of inoculation. The presentation and prognosis will vary depending on the species involved.

Non-American (Old World) cutaneous leishmaniasis:

  • Middle East, North Africa, Asia
  • L major, L  tropica, L infantum, L donovani
  • Synonyms: oriental sore, Baghdad boil, Dehli boil, saldana, Aleppo button, granuloma endemicum. 

American (New World) cutaneous leishmaniasis:

  • Central and South America
  • L mexicana, L braziliensis, L amazonensis
  • Synonyms: chiclero ulcer, uta, ulcera de Bauru, forest yaws, pian boi, bejuco.

Mucocutaneous leishmaniasis

Mucocutaneous leishmaniasis is a destructive form of leishmaniasis, which is only seen with the American species of Leishmania (Viannia subspecies). 

American mucocutaneous leishmaniasis:

  • Central and South America
  • L braziliensis, L guyanensis, L panamensis
  • Synonym: espundia. 

Diffuse cutaneous leishmaniasis

Diffuse cutaneous leishmaniasis is a rare presentation resulting from an anergic response to the parasite by the host.

Non-American diffuse cutaneous leishmaniasis:

  • Ethiopia, Kenya
  • L aethiopica.

American diffuse cutaneous leishmaniasis:

  • South America
  • L amazonensis.

Visceral leishmaniasis

Visceral leishmaniasis results from involvement of the internal organs and is usually fatal if untreated. It is also known as kala-azar or Dumdum fever. 

Non-American visceral leishmaniasis:

  • India, Southern Europe, China, North Africa, Kenya
  • L donovani, L infantum, L tropica.

American visceral leishmaniasis:

  • Central and South America
  • L chagasi.

Post-kala-azar dermal leishmaniasis

Post-kala-azar dermal leishmaniasis is a form of cutaneous leishmaniasis that can occur months to years after treatment of visceral leishmaniasis.

Non-American post-kala-azar dermal leishmaniasis:

  • Sudan, India
  • L donovani, L infantum, L tropica.

American post-kala-azar dermal leishmaniasis:

  • Central and South America
  • L chagasi. 

Leishmaniasis recidivans

Leishmaniasis recidivans is a rare, cutaneous form of leishmaniasis, occurring in patients with a good cellular immune response. It is also known as lupoid leishmaniasis.

Non-American leishmaniasis recidivans:

  • Middle East, India, Southern Europe
  • L tropica.

American leishmaniasis recidivans:

  • Central and South America
  • L braziliensis.

What are the clinical features of leishmaniasis?

Cutaneous leishmaniasis (CL)

  • CL is the most common form of leishmaniasis
  • Solitary lesions are typical but multiple lesions do occur
  • The initial lesion is a small red papule, which gradually enlarges up to 2 cm in diameter
  • Central ulceration is typical
  • Ulcers can be moist and exude pus or dry with a crusted scab
  • Sores usually appear on exposed areas of the skin, especially the face and extremities
  • The incubation time between an infected sandfly bite and lesion development is typically 2 weeks to 6 months
  • Lesions are usually painless and most resolve spontaneously often leaving residual atrophic scarring
  • Time to resolution varies between 2 months to more than a year
  • Sporotrichoid spread with lymphocutaneous nodules may occur
  • Chronic disease can occur, and there is a risk of dissemination in immunodeficient patients

Mucocutaneous leishmaniasis (MCL)

  • MCL typically occurs after spontaneous resolution or local treatment of the primary cutaneous lesion
  • May develop within months or after many years
  • Lifetime risk of developing MCL after a cutaneous lesion caused by L braziliensis is around 5%
  • Lesions typically affect the mucous membranes of the nose and mouth but the mucosal surfaces of the eyes and genital tract can also be involved
  • Without treatment, ulceration of the mucosal surfaces and destruction of the underlying tissue can occur
  • Mucosal lesions are often painful and become sites of infection, sometimes leading to sepsis
  • Can result in extreme disfigurement

Diffuse cutaneous leishmaniasis (DCL)

  • DCL is a specific disease entity, sometimes the term is incorrectly used to describe disseminated or multiple cutaneous leishmaniasis
  • Results from an anergic response to the infection due to reduced cell-mediated immunity
  • Following the primary CL lesion, non-ulcerative nodules and plaques develop
  • Lesions may be numerous and may extend over the whole body
  • Follows a chronic relapsing or progressive course
  • Often difficult to treat

Visceral leishmaniasis (VL)

  • VL affects internal organs including the spleen, liver and lymph nodes
  • Signs and symptoms include fever, weight loss, lymphadenopathy, hepatomegaly and massive splenomegaly
  • Laboratory tests may show pancytopenia and hypergammaglobulinaemia
  • Complications include gastrointestinal haemorrhage, peripheral oedema, acute renal failure and secondary bacterial infections
  • Generalised hyperpigmentation is a late feature of VL; the other name for VL, kala-azar, comes from the Hindi for ‘black fever’
  • VL may take different forms ranging from asymptomatic self-resolving disease to fulminant, life-threatening disease 

Post-kala-azar dermal leishmaniasis (PKDL)

  • PKDL is a cutaneous form of leishmaniasis resulting as a complication of VL
  • Occurs months to years after treatment of VL
  • Majority of cases occur in Sudan (up to 50%) and India (up to 10%)
  • Lesions are either indurated papules and nodules or areas of macular hypopigmentation
  • Most commonly affects the face, trunk and extremities
  • Oral mucosa and genital area may also be involved
  • Prognosis and treatment varies with location: in over 80% of Sudanese patients, the PKDL lesions will resolve spontaneously within a year, whereas in India the rate of spontaneous resolution is much lower so systemic therapy is used earlier

Leishmaniasis recidivans (LR)

  • LR occurs in patients with a good cellular immune response
  • Spontaneous resolution of the primary cutaneous lesion is followed by the development of new lesions around the edge of the primary scar
  • The lesions typically ulcerate then heal
  • The cycle continues with a chronic recurrent course, usually over decades
Cutaneous leishmaniasis in Sri Lanka

How is cutaneous leishmaniasis diagnosed?

Diagnosis of cutaneous leishmaniasis is usually based on the history and clinical appearance of the lesion. A comprehensive travel history, including historical travel due to the long incubation period, is important in non-endemic areas. The diagnosis can be confirmed by identifying the parasite on biopsy or split skin smear. Culture and PCR may also be used to confirm the diagnosis and identify the species of Leishmania, which is important when there is a risk of mucocutaneous leishmaniasis.

Serology is used to confirm the diagnosis in cases of visceral leishmaniasis.

In over 70% of cases, full thickness skin biopsy can reveal the parasite. Histopathology is also used to establish mucocutaneous leishmaniasis and visceral leishmaniasis. Complete blood counts and liver function tests should also be performed in visceral leishmaniasis.

New World leishmaniasis

What is the differential diagnosis for leishmaniasis?

The variety of clinical manifestations of CL results in a wide range of differential diagnoses:

What is the treatment for leishmaniasis?

In cutaneous leishmaniasis treatment options differ depending on whether the lesion/s is considered simple or complex.

In non-American CL, lesions are considered complex if they are larger than 4 cm, multiple, associated with lymphatic spread, persistent (> 6 months), in immunosuppressed individuals, or situated over joints or in cosmetically sensitive areas.

All cases of American leishmaniasis should be considered complex because of the risk of mucocutaneous leishmaniasis with the Viannia subspecies.

Treatment options for CL lesions include:

  • Self-healing (simple lesions only)
  • Topical non-antimonial treatments
  • Intralesional antimonials
    • Sodium stibogluconate
    • Meglumine antimoniate
  • Non-antimonial systemic therapies
  • Systemic antimonials (intravenous or intramuscular)
    • Sodium stibogluconate
    • Meglumine antimoniate.

Most cases of simple CL will resolve spontaneously without treatment but this may take many months and can result in scarring.

Systemic antimonials are the mainstay of treatment for complex CL lesions, MCL and VL. They cannot be given orally and the length of treatment may be up to 28 days for mucosal lesions. Treatment requires hospital admission and there is a risk of side effects including cardiotoxicity.

Secondary wound infections should be treated with appropriate antimicrobial therapy.

Refer to guidelines on the management of leishmaniasis published by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH) (December 2016).

Prevention of insect bites

Infection can be prevented by avoidance of sandfly bites. Because there are currently no vaccines or drugs for preventing infection, travellers to areas where leishmaniasis is prevalent should decrease their risk of being bitten by adhering to the following precautionary measures.

  • Avoid outdoor activities, especially from dusk to dawn when sandflies are the most active.
  • Wear long-sleeved shirts, long pants, and socks. Tuck shirt into pants.
  • Apply insect repellent on uncovered skin and under the ends of sleeves and pant legs. The most effective repellents are those that contain the chemical DEET (N,N-diethylmetatoluamide).
  • Spray clothing, living and sleeping areas (including bed net) with permethrin-containing insecticides.

 

Related Information

References

  • Book: Textbook of Dermatology. Ed Rook A, Wilkinson DS, Ebling FJB, Champion RH, Burton JL. Fourth edition. Blackwell Scientific Publications.
  • Alvar J, Velez ID, Bern C, et al. Leishmaniasis worldwide and global estimates of its incidence. PLoS One 2012;7(5):e35671. DOI: 10.1371/journal.pone.0035671. PubMed.
  • Gonzalez U, Pinart M, Rengifo-Pardo M, Macaya A, Alvar J, Tweed JA. Interventions for American cutaneous and mucocutaneous leishmaniasis. Cochrane Database Syst Rev 2009; CD004834. DOI: 10.1002/14651858.CD004834.pub2. Review. PubMed.
  • Gonzalez U, Pinart M, Reveiz L. Alvar J. Interventions for Old World cutaneous leishmaniasis. Cochrane Database Syst Rev 2008; CD005067. DOI: 10.1002/14651858.CD005067.pub3. Review. PubMed.
  • Hashiguchi Y, Gomez EL, Kato H, Martini LR, Velez LN, Uezato H. Diffuse and disseminated cutaneous leishmaniasis: clinical cases experienced in Ecuador and a brief review. Trop Med Health 2016;44(2):DOI: 10.1186/s41182-016-0002-0. PubMed.
  • Markle WH, Makhoul K. Cutaneous leishmaniasis: recognition and treatment. Am Fam Physician 2004;69:455-60.
  • Diagnosis and Treatment of Leishmaniasis: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH) (2016). http://cid.oxfordjournals.org/content/early/2016/11/03/cid.ciw670.full.pdf+html (Accessed on November 16, 2016).

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