Papulosquamous: reading patch tests: 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 · Papulosquamous: reading patch tests

Sample item

A nickel allergy is suspected and a patch test is applied on the back. When should the patches be read for a reliable result?

AImmediately after removal only, at 2 hoursBAt 7 days onlyCWithin 15 minutesDAt 48 hours and again at 72 to 96 hours

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

The answer and the reasoning

D. At 48 hours and again at 72 to 96 hours

Patch testing detects type IV delayed hypersensitivity, so readings are made after removal at 48 hours and again at 72 to 96 hours to catch late reactions. A 15-minute reading belongs to prick tests for type I allergy. Reading at 7 days is delayed and may miss peak responses.

Option by option

A. Immediately after removal only, at 2 hours
Two hours is too early for a type IV reaction.
B. At 7 days only
A single late reading alone is not the standard.
C. Within 15 minutes
Fifteen minutes is for immediate-type prick testing.
D. At 48 hours and again at 72 to 96 hours (correct)
Correct. Delayed hypersensitivity needs readings at 48 hours and 72 to 96 hours.

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.

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is D, At 48 hours and again at 72 to 96 hours. Patch testing detects type IV delayed hypersensitivity, so readings are made after removal at 48 hours and again at 72 to 96 hours to catch late reactions.

Why is "Immediately after removal only, at 2 hours" not the answer?

Two hours is too early for a type IV reaction.

Why is "At 7 days only" not the answer?

A single late reading alone is not the standard.

Why is "Within 15 minutes" not the answer?

Fifteen minutes is for immediate-type prick testing.

What concept does this question test?

It tests Papulosquamous: reading patch tests in Dermatology. A 15-minute reading belongs to prick tests for type I allergy. Reading at 7 days is delayed and may miss peak responses.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Papulosquamous: reading patch tests?

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.