Thread veins, or Telangiectasia, are permanently dilated capillaries, and not ‘broken capillaries’. The very thin walls (just one cell thick) of the fine facial capillaries dilate and constrict constantly throughout life to regulate the body’s temperature. As we age, they lose their elasticity and the ability to constrict, often becoming permanently dilated and visible through the skin. There are numerous causes for thread veins including:  ageing, hereditary and genetic causes, pregnancy, the rubbing of spectacles, smoking, energetic sports, temperature extremes and harsh weather exposure, hormones, skin fragility, and even constipation can be responsible.