Overview By Mayo Clinic Staff Print Blood clot in leg veinBlood clot in leg veinA blood clot in a leg vein may cause pain, warmth and tenderness in the affected area. Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins in your body, usually in your legs. Deep vein thrombosis can cause leg pain or swelling, but also can occur with no symptoms. Deep vein thrombosis can develop if you have certain medical conditions that affect how your blood clots. It can also happen if you don't move for a long time, such as after surgery or an accident, or when you're confined to bed. Deep vein thrombosis can be very serious because blood clots in your veins can break loose, travel through your bloodstream and lodge in your lungs, blocking blood flow (pulmonary embolism). Request an Appointment at Mayo Clinic Symptoms & causes July 12, 2017 Print Share on: Facebook Twitter References Deep vein thrombosis. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/dvt/. Accessed March 21, 2017. Kearon C, et al. Clinical presentation and diagnosis of the nonpregnant adult with suspected deep vein thrombosis of the lower extremity. https://www.uptodate.com/home. Accessed March 21, 2017. Deep vein thrombosis. Vascular Disease Foundation. http://vasculardisease.org/about-vascular-disease/2011-05-05-02-02-59/deep-vein-thrombosis-dvt. Accessed March 22, 2017. Lip GYH, et al. Overview of the treatment of lower extremity deep vein thrombosis (DVT). https://www.uptodate.com/home. Accessed March 21, 2017. DVT/PE facts. Centers for Disease Control and Prevention. http://www.cdc.gov/ncbddd/dvt/facts.html. Accessed March 21, 2017. Diagnosis and treatment: DVT. Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/dvt/diagnosis-treatment.html. Accessed March 22, 2017. RelatedWarfarin side effectsDeep Vein ThrombosisDoppler ultrasound: What is it used for?UltrasoundCT scanFactor V LeidenLeg swellingLeg pain Deep vein thrombosis (DVT)OverviewSymptoms & causesDiagnosis & treatmentDiagnosisTreatmentClinical trialsPreparing for your appointmentSelf-managementMore aboutIn-DepthExpert AnswersExpert BlogMultimediaResourcesNews from Mayo Clinic Advertisement Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. Advertising & Sponsorship Policy Opportunities Ad Choices Mayo Clinic Store Check out these best-sellers and special offers on books and newsletters from Mayo Clinic. The Mayo Clinic Diabetes DietThe Mayo Clinic Handbook for HappinessMayo Clinic A to Z Health GuideMayo Clinic on Digestive HealthThe Mayo Clinic Diet Online Diagnosis & treatmentRequest an AppointmentDiagnosisTreatmentClinical trialsPreparing for your appointment CON-20303972 Patient Care & Health Information Diseases & Conditions Deep vein thrombosis