A 21-year-old previously healthy Japanese woman with one-week history of fever, sore throat, chills, nausea, vomiting, abdominal pain, and watery diarrhea presented to our emergency department. Physical findings revealed eyelid edema, facial erythema, mucositis with cracked lips, cervical lymphadenopathy, and conjunctival hyperemia (Fig. 1A). Her vital signs were temperature of 39.5 °C, heart rate of 117 beats/minute, respiratory rate of 24 breaths/minute, blood pressure of 75/51 mmHg, O2 saturation of 98% on room air.