Secondary hypercoagulable states are complex clinical conditions associated with an increased risk of thrombosis in which the exact pathophysiology is poorly understood. Secondary causes of superficial thrombophlebitis include malignancy, pregnancy, use of oral contraceptives, infusion of prothrombin complex concentrates, Behcet's disease, Buerger's disease, Mondor's disease, infectious agents, conditions that promote venous stasis, intravenous catheters and intravenous drug use. Conditions that may simulate superficial thrombophlebitis include dermatophyte cellulitis at saphenous phlebectomy sites, sarcoidal granulomas, cutaneous polyarteritis nodosa, and hyperalgesic pseudothrombophlebitis in patients who test positive for human immunodeficiency virus. The distinguishing features, clinical evaluation, treatment, and histologic characteristics of the various disorders are reviewed.