DEAR MAYO CLINIC: Six months ago, my 23-year-old daughter developed superficial blood clots in her lower legs. A venogram showed some slight reflux of one leg but otherwise was normal. She was told to take an aspirin daily and wears compression stockings while standing for long periods, but last week she again developed blood clots. What should we watch for at this point? Are there ways to treat this condition permanently?

ANSWER: Blood clots in surface veins are relatively common. This condition -- known as superficial thrombophlebitis -- shouldn't be confused with blood clots that develop in deeper veins (deep venous thrombosis). Clots in surface veins are more of a nuisance, whereas clots in deep veins can be serious and even life-threatening.

Self-care techniques are often all that's needed to effectively treat superficial blood clots. But a person who has had superficial thrombophlebitis is at increased risk of developing it again. If the condition becomes a recurrent problem, medical treatment may be necessary.

Superficial thrombophlebitis frequently occurs in leg veins that are dilated or leaky (varicose veins). Blood may pool and clot in these abnormal veins, leading to pain, redness, swelling and tenderness in the affected area. The clots usually resolve on their own, typically within several weeks. But until they do, the condition can be quite uncomfortable. Elevating the affected limb, using a warm washcloth to apply heat to the area several times a day, and taking a nonsteroidal anti-inflammatory drug such as ibuprofen (Advil, Motrin) or naproxen (Aleve) can help reduce the discomfort. As in your daughter's case, compression stockings may also be helpful.

Although structural abnormalities of the veins, such as varicose veins, are a common cause of superficial thrombophlebitis, other factors can predispose a person to blood clotting in surface veins. Pregnant women and those who have just given birth are at higher risk of clotting. In a young woman, the first possibility that comes to mind, apart from pregnancy, is oral contraceptive use because hormones can predispose people to clotting. Trauma to the veins is another frequent cause of superficial thrombophlebitis. In the hospital or clinic, we often see veins that may have been injured during an intravenous (IV) line placement or a blood draw.

Superficial thrombophlebitis also can be caused by an inherited blood-clotting disorder or, rarely, by a form of cancer, such as pancreatic cancer, that may create an increase in procoagulants -- substances that promote blood clotting. When a person develops superficial thrombophlebitis more than once, or without an obvious cause, it's important to have the condition carefully evaluated by a physician to determine if an underlying medical condition could be causing the clots.

Recurrent episodes of superficial thrombophlebitis in a vein that is structurally abnormal can be treated with minor surgery to remove the abnormal segment of the vein. The procedure typically requires only a small incision, usually one-fourth inch or less. Removing the vein won't affect circulation in the leg because deeper veins can handle the increased blood volume. Another treatment option is injecting the vein with a medication (a sclerosing agent) that causes the inside of the vein to become irritated and then scar shut, preventing formation of more clots.

Your daughter should discuss with her doctor possible causes of superficial thrombophlebitis and options for long-term treatment. It may be comforting to know that unlike deep vein thrombosis -- a serious condition that requires prompt treatment with blood thinners -- superficial thrombophlebitis is rarely dangerous, and it's very unusual for a superficial thrombophlebitis to spread from surface veins to the deep veins.

-- Ian McPhail, M.D., Cardiovascular Diseases, Mayo Clinic, Rochester, Minn.

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(c) 2010 Ian McPhail, M.D., Cardiovascular Diseases, Mayo Clinic