Kawasaki disease (KD), or mucocutaneous lymph node syndrome, is a multisystem vasculitis that primarily affects infants and children. The exact cause is unknown, although several clinical and epidemiologic features of the disease suggest an infectious, likely viral, etiology that evokes an abnormal immunologic response in genetically susceptible individuals. The disease occurs primarily in children younger than 6 years, and in most cases, it occurs in individuals who live in East Asia or are of Asian ancestry. It is classically characterized by fever lasting at least 5 days (usually longer) plus 4 of the 5 following criteria:

• Bilateral bulbar conjunctival injection without exudate
• Oral mucosa changes: cracked lips, "strawberry tongue," or diffuse erythema of the mucosae
• Changes in the extremities: erythema, induration, or periungual peeling
• Exanthem
• Cervical lymphadenopathy (greater than 1.5 cm diameter)

Most individuals affected by KD follow a benign disease course. However, coronary artery aneurysms develop in 20%-25% of untreated patients. Treatment is aimed at decreasing the risk of developing coronary artery abnormalities and preventing complications from these abnormalities.

A multisystem inflammatory syndrome potentially linked to COVID-19 has been reported in children and young adults; clinical features include Kawasaki-like and toxic shock syndrome-like presentations.

Adult Patient Considerations:
KD can uncommonly occur in adults. The diagnostic criteria used for pediatric patients have not yet been validated in adults, but using these criteria, both complete and incomplete forms occur in adults. It is associated with HIV infection in up to one-fifth of cases. Lymphadenopathy and joint involvement occur with a higher frequency in adults with KD than children, and cheilitis is less frequent. Cardiac complications may occur in adults including aneurysm formation; other reported cardiac complications include valvular abnormalities and heart failure. Treatment is usually delayed in adults, given delay in diagnosis, but is similar to that in children.