OBJECTIVE: To describe dermatologic manifestations of the antiphospholipid syndrome (APS) and to investigate possible correlations between livedo reticularis and other APS manifestations. METHODS: We conducted a single-center study of 200 consecutive patients with primary or systemic lupus erythematosus-related APS. To qualify for the study, patients had to fulfill clinical and laboratory criteria from the most recent international consensus statement on classification of definite APS. Dermatologic manifestations were systematically evaluated by a dermatologist. Only dermatologic lesions that may be related to APS were included in the analyses. Correlations between livedo reticularis and other APS manifestations were determined using Fisher's 2-tailed, chi-square, and nonparametric Mann-Whitney tests. RESULTS: Dermatologic manifestations were noted in 49% of the patients and were the presenting manifestations in 30.5%. Livedo reticularis was the most frequent manifestation, observed in 25.5% of the patients. Livedo reticularis was shown to be significantly associated with cerebral or ocular ischemic arterial events (odds ratio [OR] 10.8, 95% confidence interval [95% CI] 5.2-22.5), seizures (OR 6.5, 95% CI 2.6-16), all arterial events (OR 6, 95% CI 2.9-12.6), heart valve abnormalities detected on echocardiography (OR 7.3, 95% CI 3.6-14.7), and arterial systemic hypertension (>/=160/90 mm Hg) (OR 2.9, 95% CI 1.5-5.7). Conversely, it was observed with decreased frequency in patients with only venous thrombosis (OR 0.2, 95% CI 0.1-0.5). CONCLUSION: The dermatologic manifestations of APS are frequently the presenting feature of the syndrome, and livedo reticularis is significantly associated with the arterial subset of APS.