Initial cutaneous manifestations associated with histopathological leukocytoclastic vasculitis in two patients with antiphospholipid antibody syndrome.

Antiphospholipid antibody syndrome (APS) is a multisystem disorder associated with a variety of circulating autoantibodies that target different phospholipid protein complexes. APS is sometimes lethal as a result of severe sequelae, which may be primary or secondary to the underlying disease. We report two women who presented histopathologically with leukocytoclastic vasculitis as the first cutaneous manifestation and were subsequently diagnosed with APS associated with systemic lupus erythematosus (SLE). Patient 1 presented with widespread cutaneous necrosis (WCN) with rapidly spreading pain down the lower extremities. Skin biopsy specimens from her leg purpura and WCN revealed perivascular infiltrates with neutrophils consistent with leukocytoclastic vasculitis and thromboses of small-sized dermal vessels. Patient 2 exhibited livedo reticularis, painful cutaneous nodules with necrosis, ulcer, and erythematous macules on her lower extremities, shoulder, and face. Skin biopsies of her right knee showed intravascular thrombosis of small dermal vessels and infiltration of perivascular tissues with necrotizing granulomatous vasculitis in the dermis. We found that these various cutaneous manifestations with leukocytoclastic vasculitis were present at an early stage of APS. Although progression to leukocytoclastic vasculitis in patients with APS is uncommon, our data suggest that the association between microvascular occlusions and cutaneous vessel vasculitis has a predictive value for the pathogenesis. It is important for dermatologists to recognize these cutaneous signs to permit early and accurate diagnosis and treatment.