Infections: bacterial, viral, fungal, parasitic: trichomycosis axillaris: 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: trichomycosis axillaris

Sample item

A man with marked axillary sweating notices yellow, soft, waxy sheaths that coat the hair shafts, and his vests become stained yellow. Hair does not break and there is no skin inflammation. Which organisms are responsible?

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

The answer and the reasoning

D. Corynebacterium species

Trichomycosis axillaris is a superficial bacterial colonisation of hair shafts by Corynebacterium species in sweaty areas. The treatment is shaving the hair, keeping the area dry and applying a topical antibacterial or antiperspirant.

Option by option

  • A. Malassezia furfur

    Malassezia causes pityriasis versicolor and folliculitis, not sheaths on the hair shaft.

  • B. Piedraia hortae

    Piedraia hortae causes hard black nodules, which are gritty and firmly fixed, in black piedra.

  • C. Trichophyton rubrum

    T. rubrum is a dermatophyte that causes scaling of skin and nails, not soft concretions on hair.

  • D. Corynebacterium species (correct)

    Correct. Corynebacterium forms the yellow adherent concretions on axillary hair.

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 D, Corynebacterium species. Trichomycosis axillaris is a superficial bacterial colonisation of hair shafts by Corynebacterium species in sweaty areas.

Why is "Malassezia furfur" not the answer?

Malassezia causes pityriasis versicolor and folliculitis, not sheaths on the hair shaft.

Why is "Piedraia hortae" not the answer?

Piedraia hortae causes hard black nodules, which are gritty and firmly fixed, in black piedra.

Why is "Trichophyton rubrum" not the answer?

T. rubrum is a dermatophyte that causes scaling of skin and nails, not soft concretions on hair.

What concept does this question test?

It tests Infections: bacterial, viral, fungal, parasitic: trichomycosis axillaris in Dermatology. The treatment is shaving the hair, keeping the area dry and applying a topical antibacterial or antiperspirant.

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: trichomycosis axillaris?

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.