The peculiarities of Kawasaki disease at the extremes of age

Rationale: Extremes of age is an important risk factor for the development of coronary arteries aneurysms (CAAs) associated to Kawasaki disease ( KD) along with male gender, prolonged fever and a delay in diagnosis or treatment. Patient concerns: We report two cases of KD in the extremes of age, a 5-month-old male infant and a 9-year-old child in order to underline the features of this disorder outside the typical age range of 1 to 4 years. The 5-month-old male was admitted in our clinic for generalized polymorphous exanthema and fever for approximately 7 days. The laboratory test pointed out leukocytosis and increased inflammatory biomarkers. The 9-year-old male child was admitted in our clinic for fever and submandibular adenopathy. The onset was approximately 5 days before the admission with a sudden development of unilateral, painless, submandibular lymphadenopathy for which the ENT specialist recommended antibiotics and nonsteroid anti-inflammatory drugs. In the 2nd day of admission, he presented severe desquamation of hands and soles. Diagnosis: Both cases were diagnosed with KD. The echocardiography showed no cardiac impairment in the infant, while in the older patient it revealed mild dilation of the left coronary artery. Interventions: Both patients received intravenously immunoglobulin and pulsed methylprednisolone. Outcomes: The evolution was favorable in both cases, but in the infant, the C-reactive protein levels persisted mildly elevated for approximately 2 months after the diagnosis. Lessons: The peculiarities of KD in the extremes of age are related to a higher frequency of incomplete features and an increased incidence of coronary artery lesions resulting in a delay of the diagnosis, and subsequent poorer outcomes.