Natural history and long-term outcomes of kawasaki disease following spontaneous defervescence: 31 years of experience from North India.

Intravenous immunoglobulin (IVIg) is the standard of care for the treatment of Kawasaki disease (KD) and should be administered within 10 days of the onset of fever. Management guidelines for children with KD who defervesce spontaneously are not clear. In this study, we analysed patients with KD diagnosed between 1994 and 2024 at our centre who had defervesced spontaneously, had normal acute-phase reactants, and underwent echocardiographic examination, and in whom IVIg had not been administered. We reviewed the records of patients with KD from January 1994 - December 2024. The diagnosis of KD was based on standard guidelines. Patients with KD were said to be in spontaneous defervescence when they remained afebrile for ≥ 48 h, had normal acute-phase reactants [C-reactive protein (CRP), Erythrocyte sedimentation rate (ESR)] and no coronary artery abnormalities (CAAs) on echocardiography at presentation, and when IVIg was not administered. Patients with spontaneous defervescence were subdivided into (i) early defervescence (Ed-KD), if the interval between onset of symptoms and defervescence was < 10 days, and (ii) late defervescence (Ld-KD), if the duration between onset of symptoms and defervescence was ≥ 10 days, respectively. Details of the clinical profile, laboratory investigations, and echocardiography findings were obtained from the records. Of the 1499 patients with KD enrolled during the study period, 115 patients (7.7%; 86 boys) defervesced spontaneously. The median age at disease onset was 6 years (mean, 5.6 years; range, 0.8-15 years). The median duration of fever, defined as the total duration of the febrile episode before spontaneous defervescence, was 5 days (range, 1-21 days). The median interval between illness onset (defined as fever onset) and diagnosis of KD was 15 days (range, 4-40 days), indicating that diagnosis was often made after fever had already subsided. The most common clinical feature was periungual desquamation, followed by rash, oral-mucosal changes, cervical lymphadenopathy, and conjunctival injection. Incomplete presentation was noted in 73.9% (n = 85/115) of patients. No patient has developed CAAs or other cardiac sequelae over a median follow-up of 9 months (range 2 months-156 months). The cumulative follow-up for the cohort was 235 patient-years. The 'low-risk' subgroup of patients with KD who defervesce spontaneously, and have normal acute phase reactants with no CAAs at presentation, have good clinical and coronary outcomes.