ESSENTIALS OF DIAGNOSIS
Fever, conjunctivitis, oral mucosal changes, rash, cervical lymphadenopathy, peripheral extremity changes.
Elevated ESR and CRP levels.
Risk for coronary arteritis and aneurysms.
Kawasaki disease is a worldwide multisystem disease. It is also known as the “mucocutaneous lymph node syndrome.” It occurs mainly in children between the ages of 3 months and 5 years but can occur occasionally in adults as well. Kawasaki disease occurs most often in persons of Asian or native Pacific Islander descent. Its incidence in Japan is twice that of the United States, and it occurs among siblings at twice the incidence of cases and at higher rates among parents of cases. These findings plus the known seasonality (higher incidence in winter and early spring) and occasional epidemic pattern of cases point to the inadequate current understanding of the etiology of this disease.
Kawasaki disease is an acute, self-limiting, mucocutaneous vasculitis characterized by the infiltration of vessel walls with mononuclear cells and later by IgA secreting plasma cells that can result in the destruction of the tunica media and aneurysm formation. The cause remains unknown. Epidemiologic studies show an increased risk with advanced maternal age, mother of foreign birth, maternal group B Streptococcus colonization, and early infancy hospitalization for a bacterial illness. Genetic factors are considered to play an important role in the pathogenesis of the disease. Ongoing analyses identify many gene polymorphisms, which significantly correlate with Kawasaki disease susceptibility (at least 23 to disease, and 10 to the presence of coronary aneurysms).
The Kawasaki-like disease, called multisystem inflammatory syndrome in children (MIS-C), is described in the section above on SARS-CoV-2. A table showing the distinctive features (older age, no persistence or viral association) between the two is available in the reference by Rowley.
A clinical diagnosis of classic or “complete” Kawasaki disease requires the presence of at least 5 days of fever, usually high-grade (over 39°C to 40°C) and four of the following five criteria: (1) bilateral nonexudative conjunctivitis (begins shortly after the onset of fever), (2) oral changes of erythema and cracking of lips, strawberry tongue, and erythema of oral and pharyngeal mucosa (ulcers and pharyngeal exudates are not consistent with Kawasaki disease), (3) peripheral extremity changes (erythema and edema of the hands and feet in the acute phase, or periungual desquamation, or both, within 2 to 3 weeks after the onset of fever), (4) polymorphous rash, and (5) cervical lymphadenopathy (larger than 1.5 cm, usually unilateral; least common of the clinical features). The revised case definition allows the diagnosis on day 4 in the presence of more than four principal clinical criteria, particularly when redness and swelling of the hands and feet are present.