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

We describe a rare pediatric case of Mycoplasma-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 Mycoplasma antibody titers and suggesting possible differences in their agglutination thresholds. Erythrocyte agglutination through secondary cold agglutinin disease sometimes facilitates the concomitant diagnosis of Mycoplasma 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 Mycoplasma infection. A brief discussion of clinical implications and a review of relevant literature are provided.