Double Agglutination Observed in Mycoplasma-Associated Kawasaki Disease: Pathophysiological Insights and Considerations for Treatment Strategy

We describe a rare pediatric case of <i>Mycoplasma</i>-associated Kawasaki disease, accompanied by secondary cold agglutinin disease, characterized by both erythrocyte and neutrophil agglutination. In this case, neutrophil agglutination resolved within one week, while erythrocyte agglutination persisted for four weeks, paralleling the decline in <i>Mycoplasma</i> antibody titers and suggesting possible differences in their agglutination thresholds. Erythrocyte agglutination through secondary cold agglutinin disease sometimes facilitates the concomitant diagnosis of <i>Mycoplasma</i> infection. On the other hand, neutrophil agglutination is rare, particularly in children, which poses a diagnostic challenge. This case also highlights potential diagnostic considerations and management challenges when Kawasaki disease occurs in the setting of <i>Mycoplasma</i> infection. A brief discussion of clinical implications and a review of relevant literature are provided.