In What Cases is There a Risk of Scarring from Sclerotherapy?

Following the acute setting where a patient can have an allergic reaction (rare), bruising (common) which will resorb and fade, phlebitis and deep vein thrombosis (are rare), the likelihood of hyperpigmentation is real and warrants the use of compression stockings for a period of 2 weeks to 3 months. 

Sclerotherapy,in general, has very few side effects and associated risks.  Both of these decrease as the experience of the injector increases.  The more common side effects include itching, redness, bruising, discoloration of the injected veins and hematoma formation.  Although "more common" they are not frequent.  The less common side effects would be staining, allergy and the possibility of DVT.   Even less common is the risk of stroke which can occur with the foamed solutions. Having stated all of this, it has been my experience over 20 years of injecting veins that the risks and complications are very few and far between and sclerotherapy is an extremely safe procedure when done by experienced hands.

Scarring can occur if the sclerosant is injected into the skin surrounding the vessel. If blood becomes trapped in areas treated darkening of the skin can occur.

The potential adverse side effects from sclerotherapy treatment to lower extremity veins include, but are not limited to, discoloration, ulceration and/or scarring at the site of the injections. That being said, these adverse side effects are quite rare. It is possible to develop redness and mild bruising at the treated sites, both of which typically resolve within a few weeks. Sclerotherapy is still considered first line treatment for most lower extremity veins. 

Sclerotherapy is a Safe Procedure with Minimal Risk of Scarring. However, if the sclerosant solution is mistakenly injected outside the intended blood vessel, there may be a blister and crust formation, which may result in a scar. This is not a common occurrence and may be avoided with proper technique. Patients with connective tissue disease (lupus and antiphospholipid antibody syndrome) may be at greater risk of ulceration and scarring if extravasation occurs.