Cold antibody autoimmune hemolytic anemia following varicella infection

Autoimmune hemolytic anemia (AIHA) is a rare complication of chicken pox. In adults, such AIHA is due to warm antibodies. We report a case of cold antibody AIHA following chicken pox in a young female.

A 24-year-old female presented with clinical and laboratory features consistent with hemolytic anemia 5 days after the onset of chicken pox. Her hemoglobin levels dropped rapidly during the course of admission from 7.9 to 3.8 g/dL with evidence of ongoing haemolysis in the form of rising total and indirect bilirubin. Peripheral smear revealed red cell agglutinates and erythrophagocytosis. Direct Coomb's test (DCT) was positive for C3d suggesting a cold antibody AIHA. Since test for Donath Landsteiner antibody was negative, and all other tests for common causes of hemolytic anemia were noncontributory, it was presumed to be due to chicken pox. The fulminant course necessitated a short course of oral steroids to which she responded with rise in hemoglobin and no further hemolysis. Two weeks later, her peripheral smear was normal and DCT negative.

In patients presenting with acute onset anemia following chicken pox, possibility of cold antibody AIHA must be considered and appropriate testing pursued. Despite lack of empiric evidence, short course of steroids may be beneficial if drop in hemoglobin is rapid with evidence of fulminant hemolysis, showing no abatement after first week.