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Dermatology · Vascular disorders: hereditary angioedema
Sample itemA man has recurrent non-itchy facial and laryngeal swelling without urticaria, unresponsive to adrenaline and antihistamines, and low C4. Which is the underlying defect?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
A. C1 esterase inhibitor deficiency
Hereditary angioedema results from C1 inhibitor deficiency, causing unregulated bradykinin generation. Acute attacks are treated with C1 inhibitor concentrate or icatibant, and ACE inhibitors must be avoided.
Option by option
A. C1 esterase inhibitor deficiency (correct)
Correct. C1 inhibitor deficiency causes HAE.
B. Complement C3 deficiency
C3 deficiency causes infections.
C. IgE mediated mast cell activation
IgE mediated reactions respond to adrenaline and antihistamines.
D. Excess histamine from mastocytosis
Mastocytosis responds to antihistamines.
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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