Antiphospholipid Antibody Syndrome in Systemic Lupus Erythematosus: A Rare Case Report

Antiphospholipid Syndrome (APS) is an autoimmune disorder characterized by abnormal immune responses that disrupt blood coagulation and adversely impact pregnancy outcomes. In patients with systemic lupus erythematosus (SLE), APS often results in more complex clinical presentations and heightened management challenges. Diagnosis is frequently complicated by overlapping clinical features with other disorders and by laboratory findings that may be unclear, leading to delayed recognition. This report describes a 31-year-old woman with known SLE who presented with acute left upper-extremity swelling and was found to have venous thromboses in multiple armveins. Her history of recurrent pregnancy loss and Raynaud’s phenomenon raised suspicion of autoimmune etiology. Antibody testing demonstrated persistent positivity for lupus anticoagulant (LA), anticardiolipin (aCL), and anti-β2-glycoprotein I (aβ2GP1) antibodies, confirming the diagnosis of APS. The patient was initially treated with Lovenox and subsequently switched to warfarin for long-term management because of her high-risk profile. This case highlights that APS can present with atypical manifestations and underscores the importance of early evaluation and repeat testing in patients who develop thrombosis without typical risk factors.