Kawasaki disease and juvenile systemic lupus erythematosus.

Kawasaki disease (KD) is a common vasculitis in childhood. To the authors' knowledge, only one case of juvenile systemic lupus erythematosus (JSLE)-like onset mimicking KD and another case of KD and JSLE association have previously been described. However, the prevalence of this association of the two diseases was not reported. Therefore, over 27 consecutive years, 5419 patients were followed at the Pediatric Rheumatology Unit and 271 (5%) of them met the ACR classification criteria for JSLE. Two (0.7%) of them were female. These also had KD according to European League against Rheumatism / Paediatric Rheumatology European Society (EULAR/PReS) consensus criteria and are described in this report. One case was a 13-year-old who presented all six KD criteria. Echocardiogram showed pericardial effusion, dilatation and tortuosity of right and left coronary, and her symptoms promptly improved after treatment with intravenous immunoglobulin (IVIG). Lupus diagnosis was established a few days later. Another case was a 4-year-old who had also met all six KD criteria, with improvement after IVIG, and lupus diagnosis was made 1 year later. In conclusion, the frequency of the association between these two autoimmune diseases was rare. The occurrence of a second autoimmune systemic disease in a patient with a history of KD should also be considered. Furthermore, the initial presentation of lupus may mimic KD.