PAED-0450

A 10-year-old Japanese boy presents to the hospital with pain in his elbows and knees associated with swelling of his hands and feet. On examination, he is found to be febrile with a temperature of 39°C. He is also tachycardic with a pulse rate of 120bpm and hypotensive with a blood pressure of 100/60 mmHg. Conjunctival congestion and cervical lymphadenopathy with a red tongue were also noted. What is the most probable diagnosis for this patient?