Table 1 Clinical forms of leishmaniasis
Clinical form | Principal causative agents | Common symptoms and manifestations | Complications, confounding factors and prognosis |
|---|---|---|---|
Cutaneous leishmaniasis (CL) | Leishmania infantum, Leishmania donovani, Leishmania tropica, Leishmania major and Leishmania aethiopica (Old World); L. infantum, Leishmania braziliensis, Leishmania guyanensis, Leishmania panamensis, Leishmania peruviana, Leishmania mexicana and Leishmania amazonensis (New World) [19, 36, 255] | Parasites remain localised, with patients mostly exhibiting non-healing ulcers on exposed regions of the body; a primary lesion (in New World cases) or lesions (in Old World cases) in the form of a red papule occurs 1 week to 3 months after infection, progressing into a larger plaque or nodule weeks after the development of the initial papule; an ulcer with a dark border and crusted base then forms between 1 and 6 months, occasionally paired with painless, rubbery nodules, papules or hardened masses around the site of the ulcer; surrounding lymph nodes can become enlarged and may itch, although pain is mild or absent [79, 161, 183, 254, 256, 271] | Lesions may heal spontaneously at between 1 and 36Â months, leaving a discoloured scar with social and psychological consequences for the patient; complete immunity generally occurs; complications include bacterial supra-infection [257] |
Mucocutaneous leishmaniasis (MCL) | L. braziliensis, L. panamensis, L. guyanensis and, occasionally, L. major and L. infantum (Old World); and L. amazonensis (New World) [272, 273] | Characterised by metastatic spread of parasites from the site of the sand fly bite to the upper respiratory tract mucosa, occurring concurrently with cutaneous lesions or up to 5Â years after the lesions have healed; initially, reddening and ulceration around the nasal region occurs, followed by destruction of the nasal septum, pharynx and larynx and, rarely, the eyes and genitalia [24] | The disease does not heal spontaneously and healing post-treatment can leave devastating scarring with social and psychological consequences for the patient; complications include malnutrition and pneumonia [22, 260,261,262,263] |
Kala-azar/visceral leishmaniasis (VL) | L. donovani in East Africa and the Indian subcontinent or L. infantum in Central and South America, Europe and North Africa [21, 32, 35, 104, 268] | Parasites spread to the liver, spleen and bone marrow from the site of the sand fly bite via macrophages travelling in the blood or lymphatic system; patients present with fever, fatigue, weakness, anorexia and enlargement of the liver and spleen; the incubation period is between 12 and 32Â weeks [15, 39, 57, 136] | Complications include co-infections with human immunodeficiency virus, bacterial pneumonia, tuberculosis, dysentery; fatal if left untreated, often due to severe anaemia [258, 259] |
Diffuse cutaneous leishmaniasis | L. aethiopica, L. infantum (Old World); L. mexicana, L. amazonensis (New World) [264, 270] | Presents as mixed lesions and plaques affecting limbs, buttocks and face due to an anergic response, usually in immunocompromised patients, producing non-ulcerative nodules that become chronic with a high parasite load [77, 264, 265] | A rare complication of cutaneous leishmaniasis; visually, very hard to distinguish from leprosy [264, 271] |
Disseminated leishmaniasis | L. braziliensis, L. mexicana (New World only) [266] | Presents as mixed-type lesions on multiple sites of the body, often including the mucosal regions, and a low parasite load in skin [266] | A rare complication of cutaneous leishmaniasis [266] |
Leishmaniasis recidivans | L. braziliensis (New World); L. tropica (Old World) [267] | Characterised by red papules arising from within the borders of healed cutaneous lesions and slowly progressing into chronic recurring nodules; may be a recurrence of a prior infection, occurring after months/years of dormancy; often affecting the face [18, 28, 267] | A rare complication of cutaneous leishmaniasis [24] |
Post-kala-azar dermal leishmaniasis | Cases are rare and location-specific: in Africa, symptoms include a rash of papules on the face, ears and forearms, which may heal spontaneously after a few months; in India, small macules that progress into large irregular patches on chest, back, neck and both thighs and arms, before developing into soft, painless, non-ulcerating nodules on the face, ears, trunk and genitals or, sometimes, on the hands and feet [17] | A rare complication of VL; visually, very hard to distinguish from leprosy and confirmation by microscopy may be problematic due to the low parasite load associated with the condition [24] |