The causes of appearance of spider veins can be divided into congenital and acquired factors. Congenital causes may be one of the following: hereditary, Sturge-Weber syndrome, a nevus formation in the skin supplied by the trigeminal nerve and associated with glaucoma, meningeal angiomas, and mental retardation. Among acquired causes are venous hypertension often related to the presence of venous hypertension within underlying varicose veins; flow abnormalities within the medium sized veins of the leg can also lead to the development of broken veins. Factors that predispose to the development of varicose and telangiectatic leg veins include age (usually occurs between 18 and 35 years, and peaks between 50 and 60 years, gender (females are affected approximately four to one to males), pregnancy (pregnancy is a key factor contributing to the formation of varicose and spider veins). The most important factor is circulating hormones that weaken vein walls, lifestyle/occupation (those who are involved with prolonged sitting or standing). Other acquired causes: acne rosacea, environmental damage such as that caused by sun or cold exposure, trauma to skin such as contusions or surgical incisions, radiation exposure such as that experienced during radiotherapy for the treatment of cancer, chemotherapy, carcinoid syndrome, CREST syndrome and many more.