Infections: bacterial, viral, fungal, parasitic: green nail syndrome: 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.

Try it

Dermatology · Infections: bacterial, viral, fungal, parasitic: green nail syndrome

Sample item

A dishwasher with chronic paronychia has a green-black discolouration under a partly lifted nail plate. Which organism produces the pigment responsible?

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

The answer and the reasoning

B. Pseudomonas aeruginosa

Pseudomonas aeruginosa colonises the space under a nail that has lifted from its bed (onycholysis) in wet-work occupations. Its pigments pyocyanin and pyoverdin stain the nail green. Management is to keep the hands dry, trim the loosened nail and apply topical antipseudomonal agents.

Option by option

  • A. Proteus mirabilis

    Proteus can colonise damp skin but is not the typical cause of green nail discolouration.

  • B. Pseudomonas aeruginosa (correct)

    Correct. Pyocyanin and pyoverdin from Pseudomonas stain the nail green-black.

  • C. Staphylococcus aureus

    S. aureus causes acute purulent paronychia and does not stain the nail green.

  • D. Candida albicans

    Candida causes the chronic paronychia itself but does not produce this green pigment.

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.

More Dermatology questions

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is B, Pseudomonas aeruginosa. Pseudomonas aeruginosa colonises the space under a nail that has lifted from its bed (onycholysis) in wet-work occupations.

Why is "Proteus mirabilis" not the answer?

Proteus can colonise damp skin but is not the typical cause of green nail discolouration.

Why is "Staphylococcus aureus" not the answer?

S. aureus causes acute purulent paronychia and does not stain the nail green.

Why is "Candida albicans" not the answer?

Candida causes the chronic paronychia itself but does not produce this green pigment.

What concept does this question test?

It tests Infections: bacterial, viral, fungal, parasitic: green nail syndrome in Dermatology. Its pigments pyocyanin and pyoverdin stain the nail green. Management is to keep the hands dry, trim the loosened nail and apply topical antipseudomonal agents.

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: green nail syndrome?

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.