Cutaneous Leishmaniasis

Leishmania Lowdown - Tiny Terrors

• Organism: Intracellular protozoa, genus Leishmania.
  • India: L. tropica (most common for CL), L. donovani (can cause PKDL).
• Vector: Bite of infected female Phlebotomine sandfly. (📌 Sandfly Sally Spreads Leishmania)
• Life Cycle Stages:
  • Promastigote: In sandfly gut (infective form).
  • Amastigote (LD Body): In vertebrate host macrophages (diagnostic form).

⭐ Leishman-Donovan (LD) bodies are amastigotes found intracellularly in macrophages; a key diagnostic feature on slit-skin smear or biopsy.

• Indian Hotspots: Rajasthan, Bihar, Uttar Pradesh, West Bengal. Primarily affects rural, impoverished communities.

Skin's Sad Saga - Lesion Lineup

• Localized Cutaneous Leishmaniasis (LCL):
  • Most common. Papule → nodule → ulcer at sandfly bite site.
  • Classic ulcer: round/oval, well-defined, raised indurated "volcano-like" border, crusted base. Usually painless.
  • Exposed areas: face, arms, legs. Heals with a depressed scar.
  • Synonyms: Oriental sore, Baghdad boil, Delhi boil.
• Leishmaniasis Recidivans (LR / Lupoid Leishmaniasis):
  • Chronic, relapsing papules/nodules at the edge of a healed LCL scar.
  • Shows "apple-jelly" nodules on diascopy.
• Diffuse Cutaneous Leishmaniasis (DCL):
  • Rare, anergic form. Widespread, non-ulcerating nodules/plaques. High parasite load.

⭐ "Chiclero's ulcer" is a term for chronic LCL lesions specifically occurring on the ear pinna, often seen in forest workers in endemic areas of Central and South America.

Detective Work - Nailing the Diagnosis

• Slit-skin smear: Giemsa stain for intracellular Leishman-Donovan (LD) bodies (amastigotes) in macrophages. Rapid, field-friendly.
• Biopsy & Histopathology: H&E stain shows granulomatous inflammation, lymphocytes, plasma cells, and LD bodies.
• Culture: NNN medium for promastigotes; results in 1-4 weeks, lower sensitivity than PCR.
• PCR: Detects parasite DNA; highly sensitive & specific, useful for species identification and low parasite loads.
• Montenegro Test (Leishmanin Skin Test - LST): Assesses cell-mediated immunity (Type IV hypersensitivity). Positive (induration >5mm) in cured/chronic cases, not early active disease. Indicates exposure.

⭐ Amastigotes (LD bodies) within macrophages are pathognomonic on slit-skin smear or biopsy.

Battle Plan - Kicking Out Leishmania

• Treatment goals: Parasite clearance, lesion healing, prevent relapse & Mucocutaneous Leishmaniasis (MCL).
• Factors: Leishmania species, lesion (number, size, site), host immunity, regional guidelines.

⭐ Miltefosine is the first effective oral drug for leishmaniasis, including CL.

Shield Up! - Prevention Pointers

• Personal protection:
  • Use DEET-containing repellents.
  • Sleep under insecticide-treated nets (ITNs).
  • Wear protective clothing (long sleeves/pants), especially dusk to dawn.
• Vector control:
  • Indoor residual spraying (IRS).
  • Environmental management to reduce sandfly breeding sites.

⭐ Sandflies are most active from dusk to dawn; they are weak fliers, typically found near ground level.

High‑Yield Points - ⚡ Biggest Takeaways

• Caused by Leishmania protozoa; transmitted by female phlebotomine sandfly bite.
• Characteristic lesion: painless ulcer with raised, indurated borders ("volcano sign").
• Diagnosis: Slit-skin smear (Giemsa stain) showing Leishman-Donovan (LD) bodies in macrophages.
• Montenegro test (leishmanin skin test) is typically positive in LCL, indicating Cell-Mediated Immunity (CMI).
• Treatment mainstay: Pentavalent antimonials like Sodium Stibogluconate (SSG), often intralesional.
• Notable forms: Chiclero's ulcer (pinna) and chronic Lupoid leishmaniasis (Leishmaniasis recidivans).