How long must fever persist to be considered in Kawasaki disease?

In Kawasaki disease, a diagnosis is generally considered when a fever persists for a minimum of five days. This prolonged fever is a crucial diagnostic criterion, as it helps differentiate Kawasaki disease from other febrile illnesses, especially in children. The condition is characterized by a constellation of symptoms that develop in conjunction with this fever, including changes in the mucous membranes, rash, conjunctival injection, and cervical lymphadenopathy.

A duration of five days is significant because the disease can otherwise easily be misdiagnosed or overlooked in the earlier stages, where shorter fever durations might suggest other common viral infections. Recognizing the characteristic timing and clinical presentation of Kawasaki disease is vital for prompt treatment, which can significantly reduce the risk of complications such as coronary artery aneurysms.