Sclerotherapy: Everything You Need to Know

Table of Contents
View All
Table of Contents

Sclerotherapy is a non-surgical procedure used to treat varicose veins and spider veins. It involves the injection of a special solution into the veins to seal them off. This forces blood to reroute itself to healthier veins.

In addition to reducing the appearance of varicose and spider veins, sclerotherapy is sometimes used to treat malformed lymph vessels, hemorrhoids, and hydroceles (swelling of the scrotum).

Sclerotherapy for Spider and Varicose Veins


What Is Sclerotherapy?

Sclerotherapy (sclero- meaning hardness and -therapy meaning treatment) is an in-office procedure used to address venous swelling or the abnormal accumulation of fluids in tissues. It purposefully scars the inner lining of a problematic vein so that it is eventually reabsorbed by the body.

This involves injecting a substance called a sclerosant into the affected vein(s). There are a few types of sclerosants, each of which has its own effect:

  • Detergent-based sclerosants disrupt the cellular membrane of a vein, causing walls of the vein to constrict and stick together.
  • Chemical irritants cause the vessel to initially swell, forcing out blood, and then collapse as the caustic agent damages the lining of the vein.
  • Osmotic sclerosants comprised of sodium chloride (salt) draw water out of the lining of a vein, flushing out blood and causing the dehydrated vessel to collapse.

Sclerotherapy is most often used to treat varicose veins, also known as chronic venous insufficiency, and spider veins (telangiectasia). It is one of the least invasive treatment options for these conditions, as it neither involves anesthesia nor any significant downtime.

However, it is a delicate procedure and one that can cause permanent scarring if not performed by a highly skilled and experienced dermatologist.

Spider veins may only require a single treatment, while moderate-sized varicose veins may require several.


Sclerotherapy is generally regarded as safe but is not for everyone. Sclerotherapy is absolutely contraindicated for use in people with the following health conditions:

These conditions are associated with blood clots. The use of a sclerosant can cause a clot to dislodge, triggering severe complications including pulmonary embolism (with DVT) and sudden cardiac arrest (with PE).

Pregnancy can lead to the formation of varicose veins, but sclerotherapy is contraindicated during gestation, in part because pregnancy can place a woman in a hypercoagulable state.

Sclerotherapy should be used with extreme caution in people with untreated diabetes who may experience venous ulceration. People with well-controlled diabetes are not subject to the same concerns.

People with a known allergy to sclerosant agents (which include detergents like sodium tetradecyl sulfate and chemical irritants like chromated glycerin) should not be exposed to them. There are salt-based alternatives that can be used in their place if sclerotherapy is pursued.

Possible Risks

Sclerotherapy for spider veins and varicose veins does carry certain risks, some of which are superficial and others that are potentially serious. These include:

  • Permanent hyperpigmentation (darkening) of the treated area
  • Superficial phlebitis (venous inflammation)
  • Venous matting (the development of tiny veins emanating from the site of a sclerosed vein)
  • Pyoderma gangrenosum (an autoimmune reaction leading to the formation of a venous ulcer)
  • Thrombophlebitis (the formation of a venous clot)

General risks associated with sclerotherapy for treating hemorrhoids, malformed lymph vessels, and hydroceles include:

  • Pain
  • Bleeding or hematoma formation
  • Infection

Purpose of Sclerotherapy

Sclerotherapy is considered the treatment of choice for spider veins and smaller varicose veins that cannot be managed with compression stockings or weight loss.

Spider veins are tiny, skinny veins that often appear in a web-like pattern and are visible at the surface of your skin. Spider veins can be found anywhere on the body, though they are usually found on the legs and face.

Varicose veins are enlarged, rope-like veins that bulge. They are caused by weak or damaged valves in the veins and are most commonly seen in the legs.

In addition to the cosmetic benefits sclerotherapy offers, it can also alleviate pain, aches, cramps, and burning sensations associated with these vein conditions.


Things You Might Not Know About Varicose Veins

Besides varicose and spider veins, sclerotherapy can also be used to treat concerns such as:

  • Lymph vessel malformations, the benign clumping of the vessels that carry lymph fluid (as an alternative to surgical ablation or surgical drainage)
  • Hemorrhoids, although the treatment can be less effective than rubber band ligation in treating larger, high-grade cases
  • Hydroceles, the swelling of the scrotum caused when fluids collect in the sheath surrounding the testicle (typically when the condition is persistent but not severe enough to require surgery)

Pre-Treatment Evaluation

Prior to the procedure, the healthcare provider will perform a physical examination to ensure that you have no health conditions that contraindicate treatment. An ultrasound may also be used to establish the depth and direction of larger varicose veins in order to map out the procedure.

These evaluations can help estimate how many treatments are needed to achieve the desired effect.

Large varicose veins—including so-called "trunk veins," which are thick and long—may not respond well to sclerotherapy or leave behind a visible dent after treatment. These are often more effectively treated with surgery (a.k.a. venous stripping).

How to Prepare

Even though sclerotherapy is considered minimally invasive, that shouldn't suggest that it is a walk-in procedure. Once the treatment sessions are scheduled, your healthcare provider will provide you a list of things you need to do and avoid. By following these instructions carefully, you are more likely to achieve the desired results.


Sclerotherapy is an outpatient procedure performed in a healthcare provider's office. Varicose veins and spider veins are usually treated by a dermatologist, while lymph vessel malformation, hemorrhoids, and hydroceles may be treated by a vascular radiologist, gastroenterologist, or urologist, respectively.

What to Wear

Depending on where the veins are located, you will need to wear clothes that you can either remove or that don't get in the way of the procedure. Since sclerotherapy is typically performed on the legs, you may want to wear shorts. Many healthcare providers will provide a pair of disposable shorts, called exam shorts, to change into.

Food and Drink

There are no food or drink restrictions required for sclerotherapy.


Do not take nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin, Advil (ibuprofen), Aleve (naproxen), or Celebrex (celecoxib) 48 hours before and after sclerotherapy. These drugs can promote bleeding, slow healing, and increase the risk of scarring.

You may also need to avoid tetracycline antibiotics and corticosteroids like prednisone. Tetracycline may promote hyperpigmentation, while prednisone can alter the effectiveness of the sclerosant.

Be sure your healthcare provider is aware of all drugs (prescription, over-the-counter, recreational), supplements, and herbs that you use.

What to Bring

Be sure to bring your driver's license (or other form of government ID) as well as your insurance card to check-in to your appointment. If upfront payment is required for copay or coinsurance, call beforehand to find which forms of payment they accept.

Most people can drive themselves home after sclerotherapy. With that said, if the treatment area is extensive, you may want to play it safe and bring along a friend or family member to drive you instead.

Your healthcare provider will ask you to bring a pair of compression socks or stockings to wear after the procedure. Purchase them well in advance, and wear them three to four days beforehand to ensure a snug but comfortable fit.

What to Expect the Day of the Procedure

On the morning of the sclerotherapy session, do not shave or apply lotion, moisturizer, oil, or ointment of any sort to the area of your body being treated.

Before the Treatment

After you've checked in and have signed the necessary consent forms, you will be led to a treatment room to change out of your clothes, if needed. If you are undergoing sclerotherapy for cosmetic purposes, photographs may be taken for before-and-after comparisons during follow-up visits.

During the Treatment

To start the procedure, you will be positioned on an examination table in such a way that the healthcare provider can best access the treatment area. For instance, if the area to be treated is your legs, you will lie on your back with your legs elevated a bit. Pillows and bolsters may be provided. The treatment area will then be cleansed with alcohol or some other antiseptic solution.

The sclerosing agent will then be injected into a vein with a very fine needle (usually between 30 and 33 gauge). Needles this small usually don't cause pain, but there may be some discomfort. The healthcare provider will then massage the surrounding tissue to help disperse the solution along the route of the vein.

Smaller veins are treated with liquid sclerosing solutions. Larger ones may require a foam sclerosant, which has the same effect but requires smaller doses than what would be needed with a liquid formulation. Some veins may require multiple injections per session.

Sclerotherapy sessions take between 15 and 45 minutes, depending on how extensive the treatment area is. If the treated area is small, you may only require one appointment. If more are needed, healthcare providers will usually leave several weeks between treatments to allow for proper healing.

After the Treatment

Once completed, you can change into your clothes and immediately put on your compression socks or stockings. Most people do not feel any pain or discomfort.

recovering from sclerotherapy
Illustration by Brianna Gilmartin, Verywell 


It is not uncommon to experience redness, swelling, warmth, or itching around the injection site for a couple of days after sclerotherapy. This is normal and will usually resolve on its own without treatment.

If needed, you can take Tylenol (acetaminophen) to help relieve inflammation and discomfort. Elevating your legs also helps. Bruising is uncommon but can occur.

The one thing you must do is wear your compression socks during recovery, particularly when you are on your feet. You will need to do so for seven to 14 days, depending on the extensiveness of the treatment. You do not need to wear them at night while you sleep.

In addition:

  • Do not take hot baths or sit in a hot tub or sauna. Instead, take shorter and cooler showers than normal.
  • Do not apply heated pads or any form of heat to the injection sites as this can promote inflammation and bleeding.
  • Walk at least 30 minutes a day at a slow to moderate pace for the first two weeks.
  • Avoid heavy lifting or strenuous exercise for the first two weeks.
  • Avoid direct sunlight or suntan beds as this can lead to hyperpigmentation.

After two weeks, you may feel tiny lumps in the treated area. This is caused when blood becomes trapped under the skin and is completely normal. The lumps usually dissipate over time, although it can sometimes take months. If they don't resolve, tell your healthcare provider; the lump may require drainage.

The same applies to the formation of new blood vessels around the injection site, referred to a venous matting. These can be treated with additional sclerotherapy or laser skin therapy.

When to Call a Healthcare Provider

Call your healthcare provider immediately if you experience any of the following after sclerotherapy:

  • Dizziness or fainting
  • Visual disturbances
  • Rash or hives
  • Difficulty breathing
  • Chest pain
  • Nausea or vomiting
  • Severe leg pain
  • Severe swelling of one leg
  • Coughing up blood

These could be signs of a rare but serious complication, such as allergy, thrombophlebitis, DVT, or PE.

Long-Term Care

Your healthcare provider will schedule a post-treatment assessment once the entire planned procedure is done. For spider veins and smaller varicose veins, appointments may be scheduled six to eight weeks later. For larger varicose veins, your practitioner may wait three to four months to see you.

Follow-up for sclerotherapy for other conditions is also important. During your post-treatment appointments, which usually over several months, the healthcare provider will check your response to the treatment and evaluate for any potential complications.

The efficacy of treatment may be measured by improved aesthetics and/or by the alleviation of any pain or cramping you may have experienced prior to sclerotherapy.

Once a spider or varicose vein has been completely resolved, it is unlikely to recur. If the problem persists, you may need to explore other treatments, including vascular stripping, catheter-assisted radiofrequency ablation, or endoscopic vein surgery.

Likewise, most lymphatic malformations can be treated successfully with sclerotherapy; although, multiple sessions may be required.

For early-stage hemorrhoids and simple hydroceles, sclerotherapy's success rate is generally pretty high. However, these conditions may recur and warrant a second sclerotherapy treatment or surgery (hemorrhoidectomy or hydrocelectomy, respectively).

Even if you achieve the desired results with sclerotherapy, you would be well-served to avoid the behaviors that contributed to the problem in the first place. This includes standing for long periods of time, wearing high heels, and being overweight.

By exercising, watching your diet, and regularly resting your legs throughout the day, you can avoid recurrence of this aggravating, albeit common, vascular condition.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Weiss MA, Hsu JT, Neuhaus I, Sadick NS, Duffy DM. Consensus for sclerotherapy. Dermatol Surg. 2014;40(12):1309-18. doi:10.1097/DSS.0000000000000225

  2. Yiannakopoulou E. Safety concerns for sclerotherapy of telangiectases, reticular, and varicose veins. Pharmacology. 2016;98(1-2):62-9. doi:10.1159/000445436

  3. Tomiki Y, Aoki J, Motegi S et al. Effectiveness of Endoscopic Sclerotherapy with Aluminum Potassium Sulfate and Tannic Acid as a Non-Surgical Treatment for Internal Hemorrhoids. Clin Endosc. 2019 Nov; 52(6): 581–587. doi:10.5946/ce.2019.017

  4. Bouwman FCM, Kooijman SS, Verhoeven BH. Lymphatic malformations in children: treatment outcomes of sclerotherapy in a large cohort. Eur J Pediatr. 2021; 180(3):959-66.

  5. American Society for Dermatologic Surgery. Spider Veins.

  6. Ramashankar, Prabhakar C, Shah NK, Giraddi G. Lymphatic malformations: A dilemma in diagnosis and management. Contemp Clin Dent. 2014;5(1):119-22. doi:10.4103/0976-237X.128689

  7. Institute for Quality and Efficiency in Health Care. Enlarged hemorrhoids: What surgical procedures are used to treat hemorrhoids?. In: [Internet].

  8. Taylor WSJ, Cobley J, Mahmalji W. Is aspiration and sclerotherapy treatment for hydroceles in the aging male an evidence-based treatment?. Aging Male. 2019;22(3):163-8. doi:10.1080/13685538.2018.1425987

  9. Cleveland Clinic. Sclerotherapy: Procedure detail.

  10. University of California San Francisco. Sclerotherapy.

  11. Nakano LCU, Cacione DG, Baptista-Silva JCC, Flumignan. Treatment for telangiectasias and reticular veins. Cochrane Database Syst Rev. 2017 Jul;2017(7): CD012723. doi:10.1002/14651858.CD012723

  12. Star P, Connor DE, Parsi K. Novel developments in foam sclerotherapy: Focus on Varithena (polidocanol endovenous microfoam) in the management of varicose veins. Phlebology. 2018;33(3):150-62. doi:10.1177/0268355516687864

  13. Tisi PV. Varicose veins. BMJ Clin Evid. 2011 Jan;2011:0212.

  14. National Clinical Guideline Centre (UK). Varicose veins in the legs: The diagnosis and management of varicose veins. In: NICE Clinical Guidelines, No. 168.

  15. Francis JJ, Levine LA. Aspiration and sclerotherapy: a nonsurgical treatment option for hydroceles. J Urol 2013 May;189(5):1725-9. doi:10.1016/j.juro.2012.11.008

  16. Song S-G, Kim, S-H. Optimal Treatment of Symptomatic Hemorrhoids. J Korean Soc Coloproctol. 2011 Dec; 27(6): 277–281. doi:10.3393/jksc.2011.27.6.277

By Tolu Ajiboye
Tolu Ajiboye is a health writer who works with medical, wellness, biotech, and other healthcare technology companies.