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Parasitic Skin and Soft Tissue Infections medical comic

This comic covers the protozoa and worms that invade the skin and muscles. It matches each parasite to its vector, its signature sign and its treatment — from the forms of cutaneous leishmaniasis to the skin-dwelling filarial worms, Guinea worm, Trichinella and cutaneous larva migrans — and shows which sample finds each one.

For MBBS, NEET-PG, FMGE, NEXT and USMLE revision.

Parasitic skin and soft tissue infections: what the comic covers

High-yield points

  • Leishmania tropica and L. major (Old World, sandfly Phlebotomus) cause painless papules that ulcerate on exposed skin — the oriental sore — and often heal on their own.
  • L. mexicana (sandfly Lutzomyia) causes chiclero's ulcer of the ear; L. braziliensis causes mucocutaneous leishmaniasis that destroys the nasal septum ('tapir nose') and needs systemic treatment.
  • Loa loa, the African eye worm, is spread by the day-biting Chrysops deer fly, causes Calabar swellings and can be seen crossing the eye; microfilariae show daytime periodicity; treated with DEC.
  • Onchocerca volvulus (blackfly) causes skin nodules and river blindness and is treated with ivermectin, used with caution where Loa loa is common.
  • Mansonella streptocerca (Culicoides midges) causes an itchy dermatitis with hypopigmented patches and is found on skin snips.
  • Dracunculus (Guinea worm) is caught from water containing Cyclops; the female emerges from a painful foot blister; it is nearly eradicated through safe water and filtering.
  • Trichinella spiralis from undercooked pork causes periorbital oedema, splinter haemorrhages, myositis and raised CK as larvae encyst in striated muscle.
  • Cutaneous larva migrans is a creeping, itchy track from animal hookworm larvae in human skin. Diagnosis uses skin snips, edge biopsies for Leishmania and muscle biopsy for Trichinella.

Quick questions

Which parasite causes Calabar swellings?

Loa loa, the African eye worm, transmitted by the day-biting Chrysops deer fly. The adult worm can sometimes be seen crossing the conjunctiva.

What is mucocutaneous leishmaniasis?

A form of leishmaniasis, mainly from Leishmania braziliensis, that appears months or years after a skin sore and destroys the nose, palate and throat. It needs systemic treatment.

How do people get trichinellosis?

By eating undercooked pork or wild game containing encysted Trichinella larvae. The larvae spread through the blood and settle in muscles, causing muscle pain, swelling around the eyes and raised muscle enzymes.

Is this comic free to read?

The first pages are free to preview. Members read the full comic, and you can sign up free to read one comic in full.

Read next

Topic map: Parasitic skin and soft-tissue infections in 6 branches

  1. Cutaneous leishmaniasis
    • Sandfly vector
    • Oriental sore
    • Chiclero's ulcer
    • Espundia
    • PKDL
    • Sample the edge
  2. Loa loa
  3. Onchocerca and Mansonella
  4. Guinea worm
  5. Trichinella
  6. Creeping eruptions

26 points, each linked to its comic page. Guests open the first branch; a free account opens two; Hero and Superhero members open the whole map.

Practice MCQs (21 questions, NEET-PG and USMLE style)

Question 1 (NEET-PG style)

Old World cutaneous leishmaniasis (oriental sore) caused by Leishmania tropica and L. major is transmitted by:

  1. Lutzomyia sandfly
  2. Phlebotomus sandfly
  3. Glossina (tsetse fly)
  4. Triatoma (reduviid bug)

Answer: B. Phlebotomus sandfly

Old World cutaneous leishmaniasis (oriental sore, Delhi boil) is caused by L. tropica and L. major and spread by the Phlebotomus sandfly. The sandfly injects promastigotes, which turn into amastigotes inside macrophages of the skin. Lutzomyia is the New World sandfly (L. mexicana, L. braziliensis). Glossina transmits African trypanosomiasis and Triatoma transmits Chagas disease. Comic mnemonic: Old Phlebotomists love Tropical Majors.

Question 2 (NEET-PG style)

Chiclero's ulcer, a chronic ulcer of the ear pinna in forest workers who collect chicle latex, is caused by:

  1. Leishmania mexicana
  2. Leishmania major
  3. Leishmania donovani
  4. Leishmania braziliensis

Answer: A. Leishmania mexicana

Leishmania mexicana, spread by the Lutzomyia sandfly in Central America, characteristically causes a persistent ulcer of the ear pinna, classically in chicleros who harvest chicle latex for chewing gum. L. braziliensis causes mucocutaneous leishmaniasis (espundia), L. donovani causes visceral leishmaniasis (kala-azar) and L. major causes Old World oriental sore. Comic mnemonic: Mexicans chew Chicle with their Ears.

Practice questions written by Q World Medical Comics. Not affiliated with NBEMS, NBME or the USMLE program.

High-yield flash cards (41 cards)

Vector of leishmaniasis
The female sandfly — Phlebotomus in the Old World, Lutzomyia in the New World
Causes of Old World cutaneous leishmaniasis
Leishmania tropica (urban, dry lesions, anthroponotic) and L. major (rural, wet lesions, rodent reservoir); L. aethiopica in East Africa
Oriental sore (Delhi boil, Baghdad boil)
Cutaneous leishmaniasis (L. tropica): a painless papule on exposed skin that grows, crusts and ulcerates with a raised edge, healing in months with a depressed scar

Flip, rate and review with spaced repetition. Guests can study the first 3 cards; a free account unlocks 5 and saves your progress; Hero and Superhero members study every card.

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