Thread veins can be associated with a larger incompetent reticular or varicose vein and will sometimes resolve once the reticular vein has been treated.

Injection pressure is also important since the small vessels have very thin walls, excessive pressure may cause vessel rupture. Some patients are prone to pigmentation others, are not. The reported incidence of hyper-pigmentation varies from 10-30%, it is usually not permanent but may last for up to 18 months. Persistent pigmentation, lasting over 12 months, should be seen in no more than 1-2% of patients (Goldman & Bergen 2001).

Pigmentation can be reduced by following a meticulous technique, avoid excessive injection pressures; ensure that the correct strength of sclerosant is used. Treat areas of reflux in a proximal to distal manner. Apply immediate compression to prevent re-entry of blood into the injected area and maintain for 1-3 weeks.