Introduction: Thrombocytopenia (TP) is a common complication of childhood-onset systemic lupus erythematosus (SLE), and can range from mild to life-threatening. However, severe TP with multiple hemorrhagic complications is very rare and often predicts a poor prognosis. We describe a 12-year-old Chinese girl who had a history of idiopathic thrombocytopenic purpura who developed SLE that presented as subdural hemorrhage and retinal hemorrhage because of severe TP. Patient concerns: A 12-year-old girl was admitted into our hospital because of fever, purpura, and gum bleeding lasting for 12 days. She had a history of idiopathic thrombocytopenic purpura 2 years ago previously. Diagnosis: SLE was diagnosed according to American College of Rheumatology classification criteria. Subdural hemorrhage and retinal hemorrhage were diagnosed based on brain MRI and funduscopy. Severe TP was defined as platelet count Interventions: She was treated first with intravenous immunoglobulin, but it was not efficacious. High-dose methylprednisolone showed short-term efficacy. Then, she was given a glucocorticoid and cyclosporine A plus mycophenolate mofetil. Outcomes: Fever, purpura, and gum bleeding were resolved before hospital discharge. Subdural hemorrhage and left hemorrhagic retinopathy were improved remarkably. She had a durable response to refractory TP with no adverse effects during >1-year follow-up. Conclusion: Isolated TP may be an early symptom of childhood-onset SLE . A child with severe TP is prone to develop life-threatening hemorrhagic complications. Glucocorticoids and combined immunosuppressive drugs had a durable response to refractory TP in this patient with no adverse effects.