Why Varicose Veins Are Treated With Sclerotherapy

Sclerotherapy is a non-surgical procedure for treating varicose and spider veins. It involves injecting a special solution called a sclerosant into the spider and/or varicose veins to seal them off. This forces the blood flow to reroute to healthier veins.

If you are looking to treat your spider or varicose veins, knowing the benefits and risks can help you to discuss this as a potential option with your doctor. Then, you can both work to determine if it's the right course of action for you.

recovering from sclerotherapy
Illustration by Brianna Gilmartin, Verywell 


If you’ve been diagnosed with spider or varicose veins, your doctor may prescribe sclerotherapy as one of the treatment options available to you. Sclerotherapy is used to improve the appearance of spider and varicose veins and to also relieve the other symptoms like swelling, aching, cramps, and burning sensations that sometimes accompany them.

Large varicose veins may not respond as well as small ones to sclerotherapy.


Sclerotherapy does have some risks associated with it. These include:

  • Permanent discoloration or hyperpigmentation at the site where the sclerosant has injected
  • The inflammation of a vein (phlebitis), usually only superficially
  • A blood clot forming in the veins and causing inflammation (thrombophlebitis)

If thrombophlebitis occurs, immediate medical attention should be given. If it's not treated, the inflammation and clot can spread and affect the deep venous system.

Sclerotherapy generally works well for most patients with spider and varicose veins. Most of its side effects are mild or temporary. Considering the high success rate and non-invasiveness, the benefits may seem to outweigh its risks and side effects.


You will not be able to undergo sclerotherapy treatment if you are pregnant or breastfeeding. In addition, if you fall into certain categories, you may not be regarded as a good candidate for this procedure. Your doctor will have to evaluate your individual situation and decide if you should undergo this treatment if you:

  • Have a history of thrombophlebitis
  • Have a history of blood clots
  • Have diabetes
  • Have a dialysis shunt in place
  • You smoke or are taking oral contraceptives (these two factors increase your risk of developing blood clots)

In addition to sclerotherapy, there are other alternatives for spider and varicose vein treatments that you could investigate with your doctor. There are ablation therapy, vein stripping, and laser therapy.

Before the Procedure

Once your doctor has recommended that you undergo this treatment, he/she will discuss with you the treatment goals. That is, what are your expectations of the improvement you will see?

It is best to make sure to give your doctor your full medical history, including what diseases you've been treated for in the past and if you’ve had a clot before. In addition, tell your doctor of any allergies you may have. You should also divulge any medication you are currently taking, especially if any of them are anticoagulants or blood thinners.

You should ask your doctor if compression stockings will be provided to you after the procedure. If they won't be, you should ask for the specifications of compressing stockings or garments you should buy, as you’ll need them for proper recovery soon after the procedure.

Your doctor may perform some preliminary tests before the procedure is carried out.

  • Ultrasound: This will be used to obtain images of your veins so your doctor can map them out properly and analyze how this treatment will be performed.
  • Physical Examination: Your doctor will also examine your veins by hand to check their status, and also to rule out any underlying venous disease.

Your doctor may also take photos of your affected areas. This will ensure that you are able to make a comparison with "after" pictures once the procedure is done and you start seeing results. If your doctor doesn't do this, you can take these pictures yourself.

Timing and Location

The procedure itself can take anywhere between 15 and 45 minutes, depending on the number and size of the veins to be treated. However, it is best that you factor in some waiting time before the procedure and for filling out consent forms (if any).

The procedure will take place in your doctor's office. It is non-invasive and doesn’t require any form of anesthesia.

How to Prepare

There are tips and suggestions you can follow to help prepare you for the day of the procedure.

Tips for the Day of Sclerotherapy

  • Wear clothing that gives your doctor easy access to affected areas
  • Bring a pair of loose-fitting shorts or similar clothing
  • Do not apply lotion or moisturizer on the area to be treated
  • Bring compression stockings

Loose-fitting shorts are especially advisable if the targetted areas being treated are your legs.

Your doctor may also instruct you to stop taking certain medications a number of days or weeks before your procedure. These include Minocin or tetracycline. This is because these antibiotics may cause your skin to stain if you take them around a week before or after sclerotherapy. Your doctor may prescribe alternative antibiotics for you if necessary.

Other medications you may be advised to avoid are aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs). If you do have to be on some form of painkillers, your doctor may prescribe an alternative drug.

You may also need to avoid iron supplements, vitamin E, and steroids. Steroids could include prednisone, as it can alter the effectiveness of the sclerosant.

During the Procedure

Your doctor will ask you to lie down. If the area to be treated is your legs, you may be asked to raise them up a bit. The area of skin being treated will be cleansed with alcohol or some other cleaning solution

Fine needles will be used to inject the sclerosant into the desired veins. Some veins may have to be injected multiple times. This may mean you’ll have multiple treatment sessions (with weeks in between them). The sclerosant will make the veins swell and close up.

The flow of blood through them will thus be stopped. Eventually, they will form scar tissue, fade, and be absorbed into the body. Usually, a liquid sclerosant is used, but for larger veins, a foam version may be used — this spreads and covers larger surface areas than the liquid type.

You may feel a slight stinging feeling while the treatment is ongoing. You should make sure to inform your doctor if you feel pain or serious discomfort. After the injections are done, your doctor will massage the area.


Most likely, you will be able to drive yourself home after the procedure. Your doctor will give you instructions to follow for good recovery and treatment outcomes. These steps may include:

  • Walking around frequently to prevent clots from forming
  • Avoiding strenuous exercise, activities, and sports
  • Avoiding taking NSAIDs
  • Wearing compression stockings or garments
  • Avoiding exposure of the treated areas to the sun for a couple of weeks
  • Avoiding hot baths or steam baths 

Side Effects

There a number of side effects that you may experience after undergoing sclerotherapy. While most of them are temporary and mild, some of them require medical attention and warrant treatment.

One potential side effect is swelling at the site of the injection. This should go down within a day. You may also experience some pain in the area. There also may be bruising at the site of the injection. This can last for anywhere from days to a few weeks.

Some of the veins, especially the large ones, may become lumpy and hard. This may go away on its own or your doctor may have to drain them.

There may be darkening of the treated areas. Sometimes, the treated veins get darker before they lighten and fade away. In rare cases, the darkening is permanent. There also may be reddening of the skin at the site of the injection. This is called erythema.

Itching and contact dermatitis may occur because of the compression stockings/garments. You can alleviate this with emollients and oils. You may experience an allergic reaction in the form of hives (urticaria). This can be resolved with your doctor prescribing oral antihistamines.

Revascularization may occur. This is when fine, tiny blood vessels form at the areas treated. They may go away on their own or your doctor may need to treat them with laser therapy or further injections. This condition is also known as neovascularization, blushing, or flares.

As with any procedure where the skin is penetrated or broken, there is a chance of infection with sclerotherapy — however, the chances are very small.


You can expect to see significant results from your procedure about four to six weeks after. You can compare your "before" and "after" pictures either you or your doctor have taken.

If your doctor had indicated that you may need multiple treatments to treat some particular veins, you shouldn’t expect to see noticeable results there until after those multiple treatments have been completed.

Finally, if you have chosen this treatment option, it’s wise to be positive but realistic about the results you’ll see. It's likely that not every single one of your spider or varicose veins will disappear completely.

A Word From Verywell

Sclerotherapy is a relatively easy and painless procedure that can greatly improve the appearance of your spider and/or varicose veins. However, while most people can undergo sclerotherapy successfully, it isn't the right option for everyone. Sclerotherapy could be expensive if your insurance doesn't cover it. You should make sure to extensively discuss your options with your doctor.

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