A blood clot in leg may develop in a deep vein and can cause symptoms including swelling, pain, tenderness, warmth, or reddish skin discoloration. However, some people may have a DVT without obvious symptoms. Risk factors may include extended periods of inactivity, recent surgery, long-distance travel, or a previous history of blood clots. At USA Vein Clinics, experienced vein specialists can evaluate vein-related symptoms and provide guidance based on your individual needs.