Warm IgM-mediated Autoimmune Hemolytic Anemia Causing Cutaneous Gangrene in a Child: A Case Report with Review of Literature

Background: While autoimmune hemolytic anemia (AIHA) in children is most commonly warm AIHA caused by the immunoglobulin (Ig) G type of antibodies, rarely warm AIHA may also be caused by the IgM type autoantibodies. Cutaneous gangrene is rare, mostly reported in cold AIHA. Clinical Description: A 6-year-old boy presented with fever, abdominal pain, vomiting, and red–brown urine. Examination revealed pallor, icterus, hepatosplenomegaly. Management and Outcome: Investigations showed hemoglobin of 5.5 g/dl, raised reticulocyte count and indirect bilirubin, no schistocytes, with impaired renal functions. Direct Coomb’s test was positive, and the AIHA profile indicated warm-reacting AIHA. Autoimmune profile and infective etiologies were negative. Despite commencing on pulse methyl-prednisolone, the general condition deteriorated rapidly with disseminated intravascular coagulation, decompensated shock, acute kidney injury, and evolving gangrene over both hands. Doppler showed reduced color flow with a biphasic spectrum in the right radial and ulnar arteries. Along with dialysis, supportive transfusions and antibiotics, rituximab, and plasmapheresis were started. Hematological parameters improved, and gangrenous changes gradually resolved. Conclusion: This case describes the complex and fulminating course of IgM-mediated warm AIHA in children, highlighting the critical need for prompt, aggressive treatment and close monitoring for multiorgan involvement.