Primary anetoderma: A cutaneous sign of antiphospholipid antibodies

Although a few reports in recent years have suggested that patients with antiphospholipid antibodies (aPL) are prone to developing primary anetoderma (PA), it is still unclear how often aPL are detected in unselected PA patients. We studied nine consecutive PA patients for the presence of autoimmune antibodies and disorders in general and the presence of aPL in particular. Six of the nine patients had clinical evidence of associated autoimmune disorders (Graves'disease and autoimmune haemolysis in one, systemic scleroderma in one, Hashimoto's thyroiditis in one, alopecia areata in one) and/or signs of hypercoagulability (recurrent fetal loss in two, recurrent strokes in one, recurrent deep vein thrombosis in one). In four of these six patients the onset of PA preceded these signs. Positive aPL was found in all: anticardiolipin (aCL) in six, anti-β₂-glycoprotein-I (aβ₂GPI) in six and lupus anticoagulant (LAC) in four. The most frequent isotype was IgA. Among other autoantibodies found the most frequently was antinuclear antibodies. Four of the nine patients fulfilled the criteria for antiphospholipid syndrome (APS). It is concluded that PA is an important cutaneous sign for autoimmune disorders in general and the presence of aPL in particular. Hence, the work-up of these patients should include testing for LAC as well as for all different isotypes of aCL and aβ₂GPI. We recommend that PA be added to the list of the cutaneous manifestations of APS.