Kawasaki disease without changes in inflammatory biomarkers: A case report

BACKGROUND: Kawasaki disease (KD) is diagnosed based on clinical features. Blood tests and other tests are auxiliary diagnostic tools. Since KD is a disease caused by arterial inflammation, many patients with KD have elevated levels of inflammatory biomarkers, such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and serum amyloid A protein (SAA) in blood tests. We report our experience of a patient with KD who did not have elevated levels of inflammatory biomarkers. CASE SUMMARY: A 1-year-old boy presented with a 3-day history of fever. Five of the six symptoms of KD were observed, except for changes in the lips and oral cavity. Blood tests revealed no elevation in CRP, ESR, or SAA levels. Although the blood test results were atypical, the patient was diagnosed with KD based on clinical symptoms and was admitted to the hospital for treatment. The patient was administered intravenous immunoglobulin (IVIG) and aspirin. Despite commencing treatment, the fever persisted; therefore, additional IVIG was administered, the dosage of aspirin was increased, and ulinastatin was added. Three doses of IVIG were administered and the fever resolved on day 11 of KD symptoms started. Blood tests performed during hospitalization showed normal levels of inflammatory biomarkers. We examined leucine-rich alpha-2-glycoprotein 1 - a protein that is elevated during the acute phase of KD. The protein levels did not increase during hospitalization. CONCLUSION: This case suggests the need to identify criteria and biomarkers for detecting KD conditions that do not require KD treatment.