Inflammation and Immune Pathology USMLE Step 1 Practice Question
A 16-year-old boy sustains a bee sting to his forearm and develops localized erythema, warmth, and edema within minutes. Vital signs show BP 118/76, HR 102, RR 18, temperature 37.2°C, and SpO2 98%. Physical examination reveals a 3-cm area of induration with wheal formation; no systemic urticaria or respiratory symptoms are noted. Serum tryptase is elevated at 8.5 ng/mL. The earliest increase in vascular permeability in the affected skin is most directly mediated by release of which substance from mast cells?
Answer choices
- APlatelet derived growth factor
- BHistamineCorrect answer
- CTumor necrosis factor beta
- DTransforming growth factor beta
- EInterferon gamma
- FLeukotrienes
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