Covering small or large areas of the skin, spider veins appear just below the skin & can take on the appearance of a web like structure. Spider veins can also look like a network of roots or branches of a tree.
Also known as telangiectasia, spider veins are similar to varicose veins but are much thinner in diameter (between 0.5 -1mm). Spider veins are usually closer to the skin than varicose veins but are not normally palpable (can't be touched).
Spider veins are usually blue or red compared to the dark blue or purple of larger varicose veins which have greater blood volume. They can develop anywhere on the body (including the eye) but usually develop over the face (cheeks, chin and nose) and on the legs; particularly around the ankles, below the knee and on the upper thigh area.
Spider veins are caused by pooled blood in a vein. The role of a vein is to carry oxygen depleted blood from the body back to the heart. The blood moves in one direction along the vein. Valves in a vein prevent blood from flowing backwards.
However, if the valve becomes weak blood can flow back into the vein and build up. This process is known as 'venous insufficiency'.
The process of pumping blood back to the heart from the legs can strain the vein valves. Spider veins are often found on the legs due to the higher pressures needed to pump blood from near ground level to the heart. Spider veins can also be be found on the face – see sun exposure below.
Steps can also be taken to prevent spider veins.
Whilst they may appear unsightly and cause emotional distress, spider veins are not harmful and do not require medical treatment (unlike varicose veins which often enlarge).