Pigmentary disorders: phototherapy: 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 · Pigmentary disorders: phototherapy

Sample item

Which wavelength of phototherapy is the preferred modality for generalised vitiligo?

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

The answer and the reasoning

D. Narrowband UVB at 311 nm

Narrowband UVB of 311 to 313 nm stimulates melanocyte migration from hair follicles and is immunosuppressive, and it is safer than PUVA. Treatment is given two to three times weekly for months.

Option by option

  • A. Infrared at 1000 nm

    Infrared does not stimulate repigmentation.

  • B. UVC at 254 nm

    UVC is germicidal and is not used therapeutically.

  • C. Visible blue light at 450 nm

    Blue light is not a treatment for vitiligo.

  • D. Narrowband UVB at 311 nm (correct)

    Correct. NB-UVB is the standard phototherapy.

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, Narrowband UVB at 311 nm. Narrowband UVB of 311 to 313 nm stimulates melanocyte migration from hair follicles and is immunosuppressive, and it is safer than PUVA.

Why is "Infrared at 1000 nm" not the answer?

Infrared does not stimulate repigmentation.

Why is "UVC at 254 nm" not the answer?

UVC is germicidal and is not used therapeutically.

Why is "Visible blue light at 450 nm" not the answer?

Blue light is not a treatment for vitiligo.

What concept does this question test?

It tests Pigmentary disorders: phototherapy in Dermatology. Treatment is given two to three times weekly for months.

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 Pigmentary disorders: phototherapy?

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.