Risks & Complications

Sclerotherapy side efects

Effective Sclerotherapy requires a highly-trained professional to administer. This is essential for a variety of reasons, mostly to avoid complications.

The accurate injecting small veins under ultrasound guidance is a skill that takes years to perfect. Our Clinic has over 15 years experience in performing Ultrasound Guided Injections and takes great care and pride in the accuracy of our treatments.

Patients may experience mild itching and raised, red areas at the site of application in the days immediately following the procedure.

Other side effects can include swelling, bruising, and bleeding but these should subside within 24 hours of surgery. Patients can resume their normal activities the day after the procedure, though strenuous physical exercise is prohibited for two weeks following the surgery.

Vein Surgery Risks & Complications

The risks for Sclerotherapy can be broken down into common, uncommon and rare. Common risks include bruising, trapped blood, brown discolouration of skin (Hyperpigmentation), and pink discolouration of skin (Matting).

As with any therapeutic technique, Sclerotherapy and Endovenous Laser may cause complications. The overall risk with these procedures compare quite favourably with surgery. No anaesthetic is required, no hospitalisation, no sedation and no time off work or physical activities.

Complications involved in Phlebectomy are most often benign and are resolve themselves. These complications include:

  • Scarring
  • Bleeding
  • Edema

Blisters due to wound dressing.

Common Complications


  • When: immediately after treatment
  • Cause: The treatment may disrupt underlying vessels resulting in soft tissue bleeding under the skin.
  • Predictable: Yes
  • Likelihood: More likely in patients with a bleeding tendency.
  • Prevention: Proper and adequate compression after treatment and especially the first 24 hours.
  • Management: Using anti-bruising creams
  • Resolution: Complete and spontaneous over 3 to 4 weeks.

Trapped Blood

  • Risk: Approximately 1 in 3 patients develop small localised areas of trapped blood.
  • Presents as: tender, bruised lumps with yellow discolouration
  • More likely if: Compression stockings are not worn.
  • Managed by:  Simple needle drainage at the 4 week follow-up visit.
  • Avoidable: No.
  • Predictable: No.
  • Resolution: Usually resolves completely over 4 to 6 weeks.

Diagram of an incompletely treated vessel with liquefied blood trapped within treated ends.

Skin Discolouration

  • Approximately 1 in 3 patients develop small patchy areas of pigmentation overlying the injected veins.
  • Presents as brownish stain on skin.
  • Caused by inflammatory process and may occur with scratches or surgical wounds.
  • More likely if:
  • Skin colour is olive or dark.
  • Drugs, such as Minocycline (antibiotic) or iron supplements are used during treatment.
  • Underlying Venous Disease is not treated first.
  • Trapped blood is left unreleased.
  • May be reduced by using skin bleaching agents (hydroquinone cream).
  • Unavoidable but is predictable in the instances listed above.
  • Usually resolves completely over for 2-4 months.

Pink Discolouration

  • Approximately 1 in 10 patients develop small patches of skin with new very fine blood vessels.
  • Presents as a patchy area of ‘pigmentation’ but on close inspection the tiny underlying vessels become evident.
  • Caused by skin sensitivity and tissue reactivity.
  • More likely if:
  • Skin is sensitive and reactive to trauma or keloid scarring in more severe cases.
  • Drugs, such as steroids or hormones including HRT and the oral contraceptive pill.
  • High concentrations of Sclerosant are used on Superficial Vessels.
  • Unavoidable but is predictable in the instances listed above.
  • Does not resolve spontaneously and may require additional Sclerotherapy Treatment to improve the appearance.

Uncommon Occurrences

Painful Leg (Superficial Phlebitis)

  • Risk: Approximately 1 in 70 treatments.
  • Presents as: Pinkish tender region that follows the course of the treated vein. Onset is usually 1-3 weeks after the treatment and lasts 1-3 weeks.
  • Cause: Excessive inflammation in the treated vein in susceptible individuals.
  • Predictable: No.
  • Likelihood: More likely if compression is inadequate, stockings are

Very Rare Occurrences

Small Painful Wound (Dermal Necrosis)

  • Risk: Approximately 1 in 400 treatments.
  • Presents as: A small painful ulcer at or near one of the injection sites. Approximately 5 to 10mm in size and initially quite painful.
  • Caused by: Sclerosant reaching the Arterial Vessel usually through abnormal connections within the Vascular System.
  • Predictable: No
  • More likely if: There is an underlying or hereditary tendency to have Arterio-Venous or Vascular Malformations.
  • Avoidable: Yes, but only if the existence of Arteriovenous Malformations is known prior to treatment.
  • Management: Application of dressings to cover the wounds for 4 to 8 weeks.
  • Resolution: Complete and spontaneous, although the scar is permanent.

Wound Infection

  • Risk: ~1 in 200 treatments.
  • Presents as: Small 3 to 5mm inflamed wound at the site of incision.
  • Cause: Wound contamination at the site of incision.
  • Likelihood: More likely in patients with an immune system deficiency.
  • Prevention: Proper and adequate wound care for the first 3 days.
  • Resolution: Complete over 1 to 2 weeks.

Sensory Nerve Damage

  • Risk: Approximately ~1 in 15 Phlebectomy Treatements and ~1 in 400 Ligation Treatments.
  • Presents as: Patchy loss of sensation only, the size of an egg; and occurs along the course of the treated vein.
  • Cause: Irritation or damage to Superficial Nerves adjacent to targeted vein being treated.
  • Predictable: No
  • Prevention: Yes, proper and effective use of Tumescent Anaesthesia creates a buffer between sensory nerves and the targeted vein.
  • Management: None
  • Resolution: Slow and gradual recovery. In most cases there is spontaneous return of sensation over 3-6 months; in a small number of cases the loss in sensation is PERMANENT.

Deep Venous Thrombosis (DVT)

  • Risk: Approximately 1 in 500-1000 treatments.
  • Presents as: Painful or swollen leg or calf. Often identified during the routine Ultrasound examination at the 1 to 2 weeks after treatment.
  • Cause: Blood Clot in the Deep Venous System. A greater than normal hereditary risk of Thrombosis otherwise known as Thrombophilia.
  • Predictable: Yes, a Thrombophilia screen may be performed prior to treatment to identify patients at risk.
  • More likely if: Patient has a history of being a smoker.
  • More likely if: Patient has a personal or family history of DVT in the past.
  • More likely if: Patient has recently undertaken long distance travel, greater than 4 hours, where they have been immobilised in or tight cramped seating.
  • More likely if: Patient has severe dehydration or has consumed excessive amounts of alcohol, at or around the time of treatment.
  • More likely if: Patient has recently undergone surgery or hospitalisation.
  • More likely if: Patient fails to adhere to compression treatment of the lower limbs after treatment.
  • Prevention: Yes, by addressing the measures identified above.
  • Management: Thorough investigation with the aim of identifying the cause of the Deep Venous Thrombosis. Anticoagulants should be considered and commenced immediately to treat the blood clot and to help prevent progression. Untreated or severe DVT may progress and cause pulmonary embolism or death.
  • Resolution: Over 90% of patients recover completely within 3 to 6 weeks. In addition, the DVT risk associated with treatment returns to normal after 3 to 4 weeks.

Migraine Headache / Visual Effects

  • Risk: Approximately 1 in 800 treatments.
  • Presents as: Symptoms usually occur, 10 to 20 minutes after the treatment has been completed. Symptoms may include; dizziness, light headedness; visual defects including transient blindness and last for approximately 15 to 30 minutes.
  • Cause: Sclerosant Solution reaching the Cranial Circulation.
  • Predictable: Yes.
  • More likely if: Patient has a history of migraine headache
  • More likely if: Patient has a history of a ‘hole in the heart’ or Patent Foramen Ovale
  • More likely if: A large amount of Sclerosant is injected.
  • Prevention: Yes; elevation of limbs during the injection procedure, the use of small injection volumes; the use of carbon dioxide gas (CO2) and longer recovery period in the lying position after injection.
  • Management: Observation and vital signs examination for the duration of the episode; Thorough investigation to identify the cause including Ultrasound Echocardiogram
  • Resolution: Complete and spontaneous within half to 1 hour.

Systemic Allergic Reactions

  • Risk: Approximately 1 in 1500 treatments.
  • Presents as: Rash, pallor; lightheadedness, loss of consciousness.
  • Cause: Allergic reaction to the Sclerosant.
  • Predictable: No.
  • More likely if: Patient has a known allergy to the drug in the past.
  • Avoidable: No.
  • Management: Antihistamine, oxygen; adrenaline and acute resuscitative measures.
  • Resolution: Complete within minutes.

Adjacent Nerve Damage

  • Risk: Approximately 1 in 2500 treatments.
  • Presents as: Loss of sensation or function corresponding with the nerve that has been affected.
  • Cause: Sclerosant inadvertently damaging the micro-blood supply to the affected nerve.
  • Predictable: No
  • Prevention: None
  • Management: None
  • Resolution: Slow and gradual recovery though recovery may be incomplete.