Varicose veins, especially large ones with major valve incompetence (leakage) causes venous hypertension, this in turn over time leads to dermatitis, pigmentation and venous ulceration (CEAP C5 venous disease).
Varicose ulcers are a very debilitating problem, they bleed, there is leakage of serum, they predispose patients to dermatitis and can become infected.
They usually occur on the medial (inner) aspect of ankles and unless properly treated can last for months and years.
Getting rid of the venous hypertension is the key to ulcer management and this can only be achieved with compression stockings and treating the varicose veins which cause it in the first place.
Use of dressings alone of any type are virtually useless.
Sclerotherapy is the only practical method of getting rid of all veins in such a scenario.
There are sub-tarsal venous plexus associated with varicose ulcers, these must be treated by sclerotherapy to facilitate ulcer healing.