Red man syndrome is caused by
**Core Concept**
Red man syndrome, also known as red neck syndrome or flushing reaction, is a cutaneous adverse reaction associated with the administration of certain medications, particularly vancomycin. It is characterized by flushing, erythema, and pruritus of the upper body, including the face and neck. The pathophysiology of red man syndrome involves the rapid infusion of vancomycin, leading to a transient increase in histamine release and subsequent vasodilation.
**Why the Correct Answer is Right**
The correct answer is vancomycin, a glycopeptide antibiotic used to treat serious bacterial infections. Vancomycin works by inhibiting cell wall synthesis in gram-positive bacteria, but its rapid infusion can cause a high peak concentration, leading to histamine release and the characteristic symptoms of red man syndrome. This is due to the activation of vancomycin by serum proteases, which results in the release of histamine from mast cells.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a particular medication or condition associated with red man syndrome.
**Option B:** This option is incorrect because it is not a medication commonly associated with red man syndrome.
**Option C:** This option is incorrect because it is not a medication known to cause histamine release or vasodilation.
**Clinical Pearl / High-Yield Fact**
Red man syndrome is more likely to occur with rapid infusions of vancomycin, particularly if the dose exceeds 1 g per hour. To minimize the risk of red man syndrome, vancomycin should be infused slowly over at least 60 minutes.
**Correct Answer:** A. Vancomycin