Infections: bacterial, viral, fungal, parasitic: erysipeloid: practice question

A Dermatology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dermatology · Infections: bacterial, viral, fungal, parasitic: erysipeloid

Sample item

A fishmonger sustains a finger puncture from a fish bone. Two days later the finger shows a painful, well-demarcated violaceous plaque that spreads slowly outwards with central clearing. There is no pus and no fever. Which organism is responsible?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Erysipelothrix rhusiopathiae

Erysipeloid follows inoculation of Erysipelothrix rhusiopathiae, a Gram-positive rod, in people who handle fish, meat or poultry. It gives a violaceous, slowly expanding plaque on the hand with little systemic upset, and penicillin is the drug of choice.

Option by option

  • A. Streptococcus pyogenes

    S. pyogenes erysipelas is bright red, raised and edged with fever, not a violaceous plaque with central clearing.

  • B. Mycobacterium marinum

    M. marinum causes indolent nodules over weeks after aquarium or fish exposure, not a plaque within two days.

  • C. Erysipelothrix rhusiopathiae (correct)

    Correct. This is the classic occupational infection of fish and meat handlers, presenting as a spreading violaceous finger plaque.

  • D. Vibrio vulnificus

    V. vulnificus causes rapidly progressive haemorrhagic bullae and sepsis, mostly in liver disease after seawater exposure.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is C, Erysipelothrix rhusiopathiae. Erysipeloid follows inoculation of Erysipelothrix rhusiopathiae, a Gram-positive rod, in people who handle fish, meat or poultry.

Why is "Streptococcus pyogenes" not the answer?

S. pyogenes erysipelas is bright red, raised and edged with fever, not a violaceous plaque with central clearing.

Why is "Mycobacterium marinum" not the answer?

M. marinum causes indolent nodules over weeks after aquarium or fish exposure, not a plaque within two days.

Why is "Vibrio vulnificus" not the answer?

V. vulnificus causes rapidly progressive haemorrhagic bullae and sepsis, mostly in liver disease after seawater exposure.

What concept does this question test?

It tests Infections: bacterial, viral, fungal, parasitic: erysipeloid in Dermatology. It gives a violaceous, slowly expanding plaque on the hand with little systemic upset, and penicillin is the drug of choice.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Infections: bacterial, viral, fungal, parasitic: erysipeloid?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.