Being an Internist (big 'I") not a pediatrician (small 'p'), I know of this disease on theoretical basis, never having seen a case. Here are the very basics. Call a Pediatrician.
A disease of children with the following criteria:
A. Fever at least 5 days' duration.
B. Presence of at least four of the following five: 1. Bilateral conjunctivitis. 2. Changes in the lips and oral mucosa: Dry, red, fissured lips, "Strawberry tongue", Oropharyngeal erythema. 3. Changes in the extremities: Erythema of palms and soles; Edema of hands and feet; Periungual desquamation. 4. Polymorphous rash. 5. Cervical lymphadenopathy.
C. Illness not explained by other known disease processes. Duh.
Curious associated processes include arrhythmias, coronary artery aneurysms, irritability, mitral or aortic regurgitation, myocarditis, pericarditis, anterior uveitis, arthralgias, arthritis, aseptic meningitis, hepatitis, pancreatitis, peripheral ischemia, pneumonitis, sensorineural hearing loss, urethritis with sterile pyuria, hydrops of the gallbladder.
It rides the winds from Japan: shortly after outbreaks in the East, if there are winds to the West, there are increased cases on the West Coast of the US (Ref).
A single dose of IVIG 2 g/kg; aspirin 80-100 mg/kg/day until afebrile or until day 14 of the illness, then reduced to 3 to 5 mg/kg/d. And steroids (Pubmed).
Did I mention you should call a pediatrician?