How can sclerotherapy work with small spider veins?

Closes veins: Sclerotherapy induces an inflammatory reaction in the vein (causes scar tissue) which closes the vein. This eliminated blood from filling the vein and being visible as a spider vein.

Sclerotherapy veins: Sclerotherapy is common therapy used to remove spider or varicose veins of the legs, whether for cosmetic or medical reasons. Small needles are inserted into the vein clusters & a drug is injected into them which closes the veins. FDA approved sclerosant drugs are polidocanol & sotradecol. Non FDA approved drugs used worldwide include glycerine & hypertonic saline. Can work for all size veins

Injection of veins: Sclerotherapy for spider veins is the injection of a substance into a small vein(1-2mm) that looks like spider legs. The substance injected can either be liquid or foam and is called a sclerosing solution because it either dissolves the vein or pushes the blood out of the vein so that the vein walls stick together and then dissolve. There are many solutions that can be used for sclerotherapy.