What is the recommended time window for initiating IVIG therapy in Kawasaki disease?

• A. Within the first 5 days
• B. Within the first 10 days
• C. After fever resolution
• D. Never

Answer: (B)

Initiate IVIG during the early inflammatory phase of Kawasaki disease, ideally within 10 days of fever onset. This timing is key because IVIG modulates the immune-mediated vasculitis that can lead to coronary artery aneurysms. Giving IVIG within this window significantly reduces the risk of aneurysm formation compared with delaying treatment; the benefit wanes after day 10, as inflammation can progress and damage may already have occurred. While earlier treatment is even more beneficial, the established guideline is to start within 10 days of illness. Waiting until fever resolves misses the period of active inflammation, making IVIG less effective, and is not appropriate. Never initiating IVIG is clearly incorrect because this therapy markedly lowers serious cardiac complications in Kawasaki disease.