DAT-negative autoimmune hemolytic anemia following acute hepatitis a in a pediatric patient with elevated IgA: a rare case report and literature review.

Introduction: Acute hepatitis A (AHA) is typically self-limited, with complications occurring in only 0.1% of patients. Autoimmune hemolytic anemia (AIHA) following AHA is exceedingly rare; only four adult cases have been reported. We present the first documented pediatric case of DAT-negative AIHA following severe AHA. Case presentation: A 13-year-old Middle Eastern female presented with worsening jaundice, dark urine, and breathlessness 4 weeks after a confirmed AHA diagnosis. Laboratory evaluation revealed hemolysis: hemoglobin 8.1 g/dL, LDH 560 U/L, haptoglobin 0.14 g/L, reticulocyte count 7.28%, and indirect bilirubin 19.3 mg/dL. The direct antiglobulin test (DAT) was negative on three occasions. Extensive testing excluded Glucose-6-phosphate dehydrogenase deficiency, thalassemias, hereditary spherocytosis, malignancies, and other autoimmune diseases. Immunoglobulin studies showed elevated IgA (596.2 mg/dL) with normal IgG and IgM. Clinical discussion: Diagnosis of DAT-negative AIHA was established through the exclusion of hereditary causes and confirmed by a rapid response to prednisolone 1 mg/kg/day (hemoglobin rose from 8.1 to 10.4 g/dL within 1 week). This case highlights that 3-11% of AIHA cases are DAT-negative due to IgA or IgM antibodies or low-affinity IgG. Conclusion: DAT-negative AIHA should be suspected in unexplained post-viral hemolysis despite a negative DAT. Early empiric corticosteroids can be both diagnostic and therapeutic. Key clinical lessons: (1) DAT-negative AIHA accounts for 3-11% of cases and may be IgA-mediated; (2) Systematic exclusion of hereditary hemolytic anemias is essential in high-prevalence populations; (3) Rapid response to corticosteroids supports immune-mediated etiology and justifies continued treatment.