February 25, 2025

Sclerotherapy Side Effects to Know

Sclerotherapy Side Effects to Know

Sclerotherapy Side Effects to Know

Sclerotherapy is the gold standard for treatment for spider veins and varicose veins. Some practitioners use other forms of treatment such as lasers, but these do not work for leg spider veins. But as with any medical procedure, there is a risk of side effects. Fortunately, side effects are rarely serious or permanent.

The side effect that patients most frequently ask about is the appearance of dark lines on the legs after the procedure, known as hyperpigmentation. Patients with a darker skin complexion or with dark hair color are at the greatest risk of developing this pigmentation. Though the reason is not completely clear, some believe that a form of iron that escapes from the blood in the injected veins causes the discoloration. Lines typically disappear within three to six months but can take up to two years to fully fade. In rare cases (about five percent), pigmentation can be permanent.

Other possible side effects of sclerotherapy include:

  • Hardness or lumpiness that occurs in larger injected veins and lasts for several months;
  • Raised, red-tinged areas appearing at the injection site and disappearing within several hours;
  • Bruising around the injection site lasting for several days or weeks;
  • The appearance of new tiny blood vessels around the treated area, known as matting. These may require additional injections.

Other, rarer side effects can be very serious. These include:

  • Allergic reactions to the sclerosing agent, typically involving itching and swelling;
  • Sudden onset of a swollen leg;
  • Small ulcers forming at the injection site;
  • Red streaking.

If you develop any of these more serious sclerotherapy side effects, call your doctor immediately.

To find out if sclerotherapy is the right treatment choice for your spider or varicose veins, call The Vein Institute of Jacksonville at 904.420.7576 (VEIN).

Frequently Asked Questions 

Sclerotherapy is a minimally invasive procedure used to treat spider veins and small varicose veins. A sclerosing solution is injected into the affected vein, causing it to collapse and eventually be absorbed by the body.

Hyperpigmentation—dark lines or discoloration along the treated veins—is the most frequently discussed side effect. It’s usually temporary and fades within 3 to 6 months, though in rare cases it may take up to 2 years or become permanent.

 

Patients with darker skin complexions or dark hair are more likely to develop pigmentation changes. The discoloration may be related to iron deposits from blood breakdown in the treated veins.

While rare, more serious side effects can include:

  • Allergic reactions to the sclerosing agent

  • Sudden leg swelling (may indicate a clot or serious reaction)

  • Small skin ulcers at the injection site

  • Red streaking or inflammation that spreads

IAC Accredited Vascular Testing

We are proud to be distinguished as an IAC Accredited Vascular Testing Facility. The Vein Institute adheres to the strictest national guidelines for vascular testing, demonstrating a commitment to the highest quality patient care.

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