If you are experiencing Superficial Thrombophlebitis symptoms like pain, redness, and swelling, we recommend seeking medical evaluation. It is an inflammatory condition of the veins caused by a blood clot. While leg veins are most often affected, this condition can also occur elsewhere, like in the arms and neck. Some causes for superficial clot in leg can’t be controlled or prevented, like injuring a vein or inheriting a disorder from a family member. Surface blood clot leg may not seem dangerous, but they actually have the potential to cause heart attacks or, in more severe cases, lead to amputation.