How can I differentiate Kawasaki Disease from other causes of prolonged fever in children?

Kawasaki disease (KD) should be suspected in children with prolonged fever lasting 5 days or more, especially when accompanied by specific clinical features that help differentiate it from other causes of prolonged fever. Key distinguishing features include bilateral conjunctival injection without exudate, erythema and cracking of the lips, strawberry tongue, erythema of the oral and pharyngeal mucosa, oedema and erythema of the hands and feet, polymorphous rash, and cervical lymphadenopathy ¹.

In contrast to other febrile illnesses, these mucocutaneous signs are characteristic of KD and may not be present in infections such as meningococcal disease, bacterial meningitis, pneumonia, urinary tract infection, or septic arthritis, which have their own distinct clinical signs (e.g., non-blanching rash and neck stiffness in meningococcal disease; respiratory distress signs in pneumonia; joint swelling in septic arthritis) ¹,².

Children under 1 year may present with fewer classical features of KD but are at higher risk of coronary artery abnormalities, so a high index of suspicion is necessary in this age group ¹.

Additional differentiation from toxic shock syndrome (TSS), which can also present with shock and prolonged fever, involves recognizing that KD typically lacks the profound hypotension and multi-organ failure seen in TSS, although KD with shock can mimic TSS; thus, clinical context and laboratory findings are important (Wang et al., 2024).

When assessing a child with prolonged fever, it is important to ask about the presence of these KD features since they may have resolved by the time of assessment ¹. The NICE traffic light system can aid in risk stratification but does not replace clinical judgment in identifying KD ².

In summary, prolonged fever with the constellation of mucocutaneous signs (conjunctival injection, oral changes, extremity changes, rash, lymphadenopathy) strongly suggests Kawasaki disease over other causes of prolonged fever in children ¹[(Nasr et al., 2001)].