RESUMEN
Serum sickness is an immune-complex-mediated illness that frequently occurs in patients after polyclonal antibody therapy (thymoglobulin). Although serum sickness has been described secondary to thymoglobulin therapy in adults, there are no reports in children on thymoglobulin-induced acute renal failure. We report a case of serum sickness in a 10-year-old girl who was treated for severe aplastic anemia using rabbit antithymocyte globulin (ATG). Eleven days after being started on antithymocyte globulin treatment, she developed fever, gross hematuria, arthralgia, rash, and acute renal failure. Laboratory results showed decreased complement levels, hypergammaglobulinemia, serum creatinine of 4.8 mg/dL (0.6 mg/dL at baseline), and blood urea nitrogen of 79 mg/dL (28 mg/dL at baseline). Peritoneal dialysis was required for 14 days. The patient's symptoms resolved after 13 days on treatment with a short course of high-dose steroids for 3 days, followed by a prednisolone taper. Early recognition and accurate diagnosis is the key for managing thymoglobulin-induced serum sickness, as treatment is highly effective at achieving good outcomes.