A patient develops a rash and joint pain several days after receiving an antivenom serum. Histology shows vasculitis with immune complex deposition. This reaction is characteristic of which type of hypersensitivity?

The correct answer to the question "A patient develops a rash and joint pain several days after receiving an antivenom serum. Histology shows vasculitis with immune complex deposition. This reaction is characteristic of which type of hypersensitivity?" is Option C: Type III (Immune Complex).

The other options — A) Type I (Immediate), B) Type II (Cytotoxic), D) Type IV (Delayed) — are incorrect for this USMLE Exam Prep question. As explained above: This describes serum sickness, a classic example of a Type III hypersensitivity reaction. It involves the formation of circulating immune complexes that deposit in tissues, leading to inflammation, v…