Sneddon Syndrome with or without Antiphospholipid Antibodies: A Comparative Study in 46 Patients

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Abstract
Sneddon syndrome is characterized by the association of livedo reticularis and cerebral ischemic arterial events (stroke or transient ischemic attack). Reported prevalence of antiphospholipid antibodies is highly variable. We conducted this study to compare the clinical and pathologic features of patients with Sneddon syndrome according to the presence or absence of antiphospholipid antibodies. Forty-six consecutive patients with Sneddon syndrome were analyzed. All were examined by the same dermatologist who classified the livedo of the trunk according to the regularity of the fishnet reticular pattern and according to the thickness of the fishnet reticular pattern (> or = 10 mm = large; < 10 mm = fine). Skin biopsies were systematically performed, from both the center and the violaceous netlike pattern in 38 patients. Antiphospholipid antibodies-positive Sneddon syndrome was defined by the presence of lupus anticoagulant or abnormal titers of anticardiolipin antibodies on repeated determinations. Group I consisted of 27 antiphospholipid antibodies-negative patients and Group II, of 19 antiphospholipid antibodies-positive patients. All patients except I in Group II had irregular livedo reticularis. Large livedo racemosa was more frequently observed in Group I (89%) than in Group II (21%, p < 0.001). On skin biopsy, arteriolar obstruction was detected in only 8 patients (4 in each group). The following parameters were not statistically different between the 2 groups: gender, mean age at detection of livedo, mean age at first clinical cerebral event, hypertension, Raynaud phenomenon, patients with extracerebral and extracutaneous arterial or arteriolar thrombosis or stenosis, patients with venous thrombosis, and women with 2 fetal losses or more. In contrast, seizures (11% in Group I versus 37% in Group II, p < 0.05), mitral regurgitation on echocardiogram (19% versus 53%, p = 0.02), and thrombocytopenia < 150,000/muL (0% versus 42%, p < 0.005) were more frequently observed in Group II. The number of events per year of follow-up was lower with antiplatelet therapy (0.08 versus 0.5) in Group I, but was not different with anticoagulation (0.056 versus 0.06). Antiphospholipid antibodies-negative and -positive patients with Sneddon syndrome belong to close but different subsets of Sneddon syndrome.