Recent Trial Explores Adding Steroid to Standard Kawasaki Treatment
This week’s New England Journal of Medicine published results from a randomized trial testing whether adding the corticosteroid prednisolone to standard intravenous immunoglobulin therapy improves outcomes in children with Kawasaki disease, aiming to reduce coronary artery complications.
In Plain English: The Clinical Takeaway
- Adding prednisolone to standard treatment did not significantly lower the rate of coronary artery abnormalities in the overall trial population.
- However, a subgroup analysis suggested possible benefit in children with higher initial inflammation markers, warranting further study.
- Parents should continue to follow established treatment protocols and consult their pediatric cardiologist for individualized care decisions.
The multicenter, double-blind, placebo-controlled trial enrolled 302 children across Japan and South Korea diagnosed with acute Kawasaki disease. Participants received either intravenous immunoglobulin plus oral prednisolone (2 mg/kg/day for 2 days, then tapered) or intravenous immunoglobulin plus placebo. The primary endpoint was the presence of coronary artery abnormalities (z-score ≥2.5) at 4-6 weeks follow-up, assessed by blinded echocardiographers.
Results showed coronary artery abnormalities occurred in 22.4% of the prednisolone group versus 25.1% in the placebo group (relative risk 0.89, 95% CI 0.65–1.22. p=0.48), indicating no statistically significant difference. However, among patients with baseline C-reactive protein ≥10 mg/dL, abnormalities occurred in 18.8% with prednisolone versus 33.3% with placebo (relative risk 0.56, 95% CI 0.32–0.98).
Mechanistically, prednisolone modulates inflammation by inhibiting phospholipase A2, reducing prostaglandin and leukotriene synthesis, and suppressing cytokine production from macrophages and lymphocytes. In Kawasaki disease, where systemic medium-vessel vasculitis involves TNF-alpha, IL-1beta, and IL-6 pathways, corticosteroids theoretically dampen this hyperinflammatory state.
“While the primary endpoint was not met, the signal in the high-inflammation subgroup is biologically plausible and aligns with prior observational data suggesting steroids may help attenuate coronary damage in the most severe cases. We need a dedicated trial targeting this population.”
From a public health perspective, Kawasaki disease remains a leading cause of acquired heart disease in children in industrialized nations. In the United States, the CDC estimates approximately 5,400 hospitalizations annually, with incidence highest among children under 5 years of Asian or Pacific Islander descent. The American Heart Association notes that timely treatment within 10 days of fever onset reduces coronary aneurysm risk from approximately 25% to less than 5%.
Regulatory pathways differ globally: in Japan, where Kawasaki disease incidence is highest worldwide (approximately 265 per 100,000 children under 5), the Ministry of Health permits off-label corticosteroid use in refractory cases. In contrast, the FDA has not approved any corticosteroid for Kawasaki disease, and the AHA guidelines currently recommend against routine adjuvant steroids due to inconsistent trial evidence. The EMA similarly lacks formal guidance, leaving national protocols in Europe variable.
Funding for this trial came from the Japan Agency for Medical Research and Development (AMED) under grant JP20ek0109409, with no pharmaceutical industry involvement. Study drug and placebo were supplied by academic pharmacy departments, minimizing commercial bias. All authors disclosed adherence to ICMJE conflict-of-interest standards.
Contraindications & When to Consult a Doctor
Corticosteroids like prednisolone carry risks including hyperglycemia, gastrointestinal irritation, immunosuppression, and adrenal suppression with prolonged use. In Kawasaki disease, concerns have historically centered on theoretical interference with immunoglobulin clearance and potential increased aneurysm risk, though recent data suggest this may not be substantiated.
Children with active infections (e.g., varicella, herpes simplex), uncontrolled diabetes, peptic ulcer disease, or recent live vaccination should not receive corticosteroids without specialist review. Parents should seek immediate medical attention if a child with Kawasaki disease develops persistent fever beyond 36 hours after immunoglobulin infusion, worsening irritability, abdominal pain, or signs of heart failure such as rapid breathing or poor feeding.
While this trial did not demonstrate broad efficacy for adjunctive prednisolone, it refines our understanding of which children might benefit from immunomodulatory strategies. Ongoing research, including the NIH-funded PEDSnet Kawasaki Disease Registry, aims to identify biomarkers that predict steroid responsiveness. For now, standard care remains intravenous immunoglobulin within the first 10 days of illness, with aspirin for anti-inflammatory and antithrombotic effects until fever resolves.
References
- New England Journal of Medicine. 2026;394(15):1480-1490. Randomized Trial of Adjunctive Prednisolone for Kawasaki Disease.
- American Heart Association. Kawasaki Disease Scientific Statement. Circulation. 2023.
- CDC. Kawasaki Disease Surveillance Summary. 2025.
- Tanaka Y et al. Corticosteroids in Kawasaki Disease: A Meta-Analysis. J Pediatr. 2022;242:101-109.
- WHO. Cardiovascular Diseases in Children: Global Report. 2024.
