Pediatric Lupus Anticoagulant–Hypoprothrombinemia Syndrome: A Systematic Review of the Literature

Lupus anticoagulant–hypoprothrombinemia syndrome (LAHS) is a rare acquired bleeding disorder characterized by the coexistence of lupus anticoagulant (LA) and reduced factor II (prothrombin) levels. Although frequently described in children and adolescents, the clinical spectrum and therapeutic management remain poorly standardized. The aim of this study is to systematically review the literature published between 2005 and 2024 regarding pediatric LAHS. Thirty-six studies published between 2005 and 2024 were included. Demographic data, bleeding phenotype, antiphospholipid antibody profile, factor II levels, underlying etiologies, treatment strategies, and outcomes were extracted and analyzed. A total of 59 pediatric patients were identified (female/male ratio = 36/23). The median age was 7 years. Bleeding manifestations were present in 94.1% of patients, with major bleeding occurring in 35.2%. The most common manifestations were ecchymoses, epistaxis, hematuria, and gingival bleeding. Intracranial hemorrhage was rare. LA positivity was reported in 98% of tested patients, whereas anticardiolipin and anti-β2-glycoprotein I antibodies were detected in 48 and 43.7%, respectively. Triple antiphospholipid antibody positivity was observed in 40% of fully tested patients. Mean/median factor II levels were 19.8 and 13.5%, respectively. Systemic lupus erythematosus represented the most frequent associated condition, followed by viral infections. Corticosteroids were the most commonly administered immunomodulatory therapy (72.5%). Complete remission occurred in 90% of cases. Pediatric LAHS is predominantly associated with severe hypoprothrombinemia and clinically significant bleeding. Despite the high prevalence of hemorrhagic manifestations, outcomes are generally favorable. Early recognition of the syndrome is essential to avoid diagnostic delays and potentially life-threatening bleeding complications.