Therapeutics: photodynamic therapy: 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 · Therapeutics: photodynamic therapy

Sample item

Photodynamic therapy for actinic keratosis uses which combination?

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

The answer and the reasoning

D. A topical photosensitiser prodrug such as methyl aminolevulinate followed by red light

Photodynamic therapy applies aminolevulinic acid or methyl aminolevulinate, which is converted to protoporphyrin IX in abnormal cells, followed by red light that generates reactive oxygen species. It treats actinic keratoses and superficial BCC and often causes burning pain during illumination. PUVA uses psoralen and UVA instead.

Option by option

  • A. Oral psoralen followed by UVA

    Oral psoralen with UVA is PUVA.

  • B. Systemic retinoid with infrared light

    Retinoid with infrared light is not photodynamic therapy.

  • C. Topical steroid with blue light

    Steroid with blue light is not a recognised therapy.

  • D. A topical photosensitiser prodrug such as methyl aminolevulinate followed by red light (correct)

    Correct. A topical photosensitiser with red light defines photodynamic therapy.

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, A topical photosensitiser prodrug such as methyl aminolevulinate followed by red light. Photodynamic therapy applies aminolevulinic acid or methyl aminolevulinate, which is converted to protoporphyrin IX in abnormal cells, followed by red light that generates reactive oxygen species.

Why is "Oral psoralen followed by UVA" not the answer?

Oral psoralen with UVA is PUVA.

Why is "Systemic retinoid with infrared light" not the answer?

Retinoid with infrared light is not photodynamic therapy.

Why is "Topical steroid with blue light" not the answer?

Steroid with blue light is not a recognised therapy.

What concept does this question test?

It tests Therapeutics: photodynamic therapy in Dermatology. It treats actinic keratoses and superficial BCC and often causes burning pain during illumination. PUVA uses psoralen and UVA instead.

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 Therapeutics: photodynamic therapy?

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.