Hair disorders: trichorrhexis nodosa: 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 · Hair disorders: trichorrhexis nodosa

Sample item

Microscopy of fragile hair shafts shows nodes where the cortex splits into fibres, resembling two paintbrushes pushed together. What is the diagnosis?

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

The answer and the reasoning

D. Trichorrhexis nodosa

Trichorrhexis nodosa is the commonest hair shaft defect, with nodes where the cortex frays, giving a paintbrush appearance and breakage. It is usually acquired from chemical or physical trauma, but it can also occur in argininosuccinic aciduria or hypothyroidism. Management is gentle hair care.

Option by option

  • A. Pili torti

    Pili torti shows flattened hair twisted along its axis.

  • B. Trichorrhexis invaginata

    Trichorrhexis invaginata gives bamboo hair in Netherton syndrome.

  • C. Monilethrix

    Monilethrix shows regular beaded nodes and elliptical swellings.

  • D. Trichorrhexis nodosa (correct)

    Correct. Paintbrush-like frayed nodes indicate trichorrhexis nodosa.

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 D, Trichorrhexis nodosa. Trichorrhexis nodosa is the commonest hair shaft defect, with nodes where the cortex frays, giving a paintbrush appearance and breakage.

Why is "Pili torti" not the answer?

Pili torti shows flattened hair twisted along its axis.

Why is "Trichorrhexis invaginata" not the answer?

Trichorrhexis invaginata gives bamboo hair in Netherton syndrome.

Why is "Monilethrix" not the answer?

Monilethrix shows regular beaded nodes and elliptical swellings.

What concept does this question test?

It tests Hair disorders: trichorrhexis nodosa in Dermatology. It is usually acquired from chemical or physical trauma, but it can also occur in argininosuccinic aciduria or hypothyroidism. Management is gentle hair care.

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 Hair disorders: trichorrhexis nodosa?

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.