Infections: erythema induratum of Bazin: 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: erythema induratum of Bazin

Sample item

A 30-year-old woman has recurrent painful, deep violaceous nodules on the calves that ulcerate in cold weather. Biopsy shows lobular panniculitis with granulomas and vasculitis. Mantoux is strongly positive. What is the diagnosis?

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

The answer and the reasoning

D. Erythema induratum of Bazin

Erythema induratum is a tuberculid, a hypersensitivity reaction to distant tuberculous antigen, and presents with calf nodules in women. It shows a lobular panniculitis with vasculitis and may ulcerate. Erythema nodosum is a septal panniculitis that does not ulcerate.

Option by option

  • A. Erythema nodosum

    Erythema nodosum is a septal panniculitis on the shins that heals without ulceration.

  • B. Polyarteritis nodosa

    Polyarteritis nodosa shows necrotising arteritis of medium vessels, not tuberculin positivity with granulomas.

  • C. Lupus vulgaris

    Lupus vulgaris is a plaque of true cutaneous tuberculosis, typically on the face, with apple-jelly colour.

  • D. Erythema induratum of Bazin (correct)

    Correct. Calf nodules with ulceration, lobular panniculitis and strong tuberculin reactivity fit this tuberculid.

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, Erythema induratum of Bazin. Erythema induratum is a tuberculid, a hypersensitivity reaction to distant tuberculous antigen, and presents with calf nodules in women.

Why is "Erythema nodosum" not the answer?

Erythema nodosum is a septal panniculitis on the shins that heals without ulceration.

Why is "Polyarteritis nodosa" not the answer?

Polyarteritis nodosa shows necrotising arteritis of medium vessels, not tuberculin positivity with granulomas.

Why is "Lupus vulgaris" not the answer?

Lupus vulgaris is a plaque of true cutaneous tuberculosis, typically on the face, with apple-jelly colour.

What concept does this question test?

It tests Infections: erythema induratum of Bazin in Dermatology. It shows a lobular panniculitis with vasculitis and may ulcerate. Erythema nodosum is a septal panniculitis that does not ulcerate.

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 Infections: erythema induratum of Bazin?

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.