Firstly, despite what you may think, having them has nothing to do with having sensitive or delicate skin. "The most common causes of spider veins are age and genetics," confirmed Dr David Jack , a cosmetic doctor who treated my mum’s spider veins pretty miraculously. "While it’s true that the paler your skin, the more likely they are to show through, having pale or sensitive skin doesn’t make you more predisposed to them. In fact, when people talk about 'thin skin' in relation to spider veins, it’s a bit of a misnomer. The part of the skin that can be thinner isn’t the part where the spider veins appear."Instead, spider veins are caused when the blood vessels dilate to try and compensate for irregular or constricted blood flow. While certain external factors like sun damage can certainly make them worse, the primary causes are almost all internal. "Aside from genetics and age, high blood pressure and stress can also bring about spider veins," confirmed Dr Jack. "It’s not like rosacea where you flare it up by using the wrong skincare. It’s more about how your body is functioning internally."