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Can Sclerotherapy cause blood clots?

I’ve heard that occasionally, small lumps of clotted blood can be felt after sclerotherapy. Aren’t blood clots quite dangerous?

The information provided by medical professionals in the Q&A is for informational purposes only, and is not a substitute for individualized medical advice, diagnosis or treatment by a qualified health care provider.


Replied on 2/17/2010

By: Bella MD Laser Vein and Aesthetic Center  |  David A. Engleman MD, FACC
Dallas, TX

The idea is to clot the spider veins. They are not dangerous.

Replied on 2/17/2010

By: The Jacksonville Vein Center  |  Geoffrey L. Risley, M.D., F.A.C.S.
Alfred D. Harding, Jr., M.D., F.A.C.S.

Jacksonville, FL

Thrombophlebitis can occur with sclerotherapy. If they occur in the small superficial veins they are not dangerous merely painful and can be lessened by aspiration of the thrombus. Thrombus in the large, deep veins is a dangerous condition, but this rarely occurs with sclerotherapy of the superficial veins.

Replied on 2/17/2010

By: General Vascular Surgery Group  |  Michael D. Ingegno, M.D.
Robert O’Neil Gingery, M.D.
Lamont D. Paxton, M.D.

San Ramon, CA

Surface vein trapped blood/blot clots are quite common after sclerotherapy, and generally do not develop into dangerous Deep Vein Blood clots.

Replied on 2/17/2010

By: Heart and Vein Center  |  Rodolfo D. Farhy, MD, FACC, FAHA
Lathrup Village, MI

Blood clots on the veins are dangerous if they affect the deep vein system. Otherwise might be uncomfortable, perhaps painful but no dangerous.

Replied on 2/18/2010

By: VeinSolutions - Edina  |  
Edina, MN

Deep vein blood clots are dangerous, however it is highly unlikely that this would occur after sclerotherapy. What you have heard about is "trapped blood" at the injection sites. This is very superficial and not dangerous. You physician can simply drain the blood.

Replied on 2/18/2010

By: Angelo N. Makris MD   |  Angelo N. Makris, M.D. Interventional Radiology Center
Oak Brook, IL

Yes it can, but they are only dangerous when they form in the deep veins.

Replied on 2/21/2010

By: Innovative Vein  |  Paul Cheatum, M.D.
Wichita, KS

These hard areas are areas of trapped blood. They are similar to a clot, but are not dangerous. They will be absorbed with time.

Replied on 2/23/2010

By: Miller Vein  |  Jeffrey H. Miller, M.D.
Steven K. Wang, M.D.
Michael E. Lulenski, M.D.
Zoe Deol, M.D.

Novi, MI

Deep Venous Thrombois (DVT) is dangerous. DVT is rare with sclerotherapy which can occasionally cause superficial blood clots (which are typically not dangerous).

Replied on 2/24/2010

By: Laser Vein Center  |  Thomas Wright, M.D., F.A.C.P., R.V.T.
O'Fallon, MO

Sclerotherapy can cause blood clots with an open vessel which theoretically could present a concern. In practice however this is Extremely rare.
These type of "blood clots" are termed THROMBUS, which is a clot within an open blood vessel.
The lumps that you are referring to is clotted blood in a treated vein which by the treatment has been eliminated from the circulation. These types of clot are termed "Hematomas" which have essentially no health threat because they are trapped in the tissue and cannot travel. Typically these should be drained for purposes or comfort as well as appearance.

Replied on 8/31/2010

By: Vanish Vein and Laser Center  |  John Landi,MD,FACS,RPVI,RPhS, Diplomate ABVLM
Naples, FL

Blood clots could be dangerous if they involve the deep veins of the leg(DVT). This should not happen from sclerotherapy. After sclerotherapy blood can become trapped in the small veins and clot but this usually resolves over time and is not dangerous.

Replied on 2/8/2013

By: Vein Treatment and Aesthetic Center  |  Jay Richardson, MD, FACS
Shawnee Mission, KS

In almost every treatment clots will occur where the injection took place. These clots will not travel or move to another location unless a very large vein was treated. This treatment is used mainly on smaller veins - veins that are close to the skin and not surrounded by muscles.

Replied on 5/13/2013

By: The Kimmel Institute  |  Dr. Richard Kimmel
Boca Raton, FL

Sclerotherapy is a term for the treatment of veins by injection of a medication into the vessel to cause it to close down. It can be done to both small spider veins, and to larger varicose veins. It is VERY rare for injection Sclerotherapy to cause a deep vein blood clot, however it can happen. More commonly, a small percentage of patients may get a superficial phlebitis, or inflammation with clot, of the veins that were injected. This is NOT a deep vein problem (which is much more serious, sometimes leading to a blood clot traveling to the lungs and even death). In experienced hands, Sclerotherapy is a safe and effective treatment for many vein problems.

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