The causes of<unk>  can be divided into congenital and acquired factors. Genetic Goldman states that "numerous inherited or congenital conditions display cutaneous<unk> ". These include: *Bloom syndrome (homozygous null mutation in BLM DNA repair enzyme. similar mechanism and etiology to ataxia<unk>  * Naevus flammeus (port-wine stain) *Klippel–Trenaunay syndrome *Maffucci syndrome (multiple enchondromas and hemangiomas) * Hereditary hemorrhagic<unk>  (Osler–Weber–Rendu syndrome) *Ataxia–telangiectasia *Sturge–Weber syndrome, a nevus formation in the skin supplied by the trigeminal nerve and associated with facial port-wine stains, glaucoma, meningeal angiomas and intellectual disabilities * Hypotrichosis–lymphedema–telangiectasia syndrome, caused by mutation in transcription factor SOX18 Venous hypertension In the past, it was believed that leg varicose veins or<unk>  were caused by high venous pressure or "venous hypertension". However it is now understood that venous reflux disease is usually the cause of these problems.<unk>  in the legs is often related to the presence of venous reflux within underlying varicose veins. Flow abnormalities within the medium-sized veins of the leg (reticular veins) can also lead to the development of<unk> . Factors that predispose to the development of varicose and telangiectatic leg veins include * Age * Sex: It used to be thought that females were affected far more than males. However, research has shown 79% of adult males and 88% of adult females have leg<unk>  (spider veins). * Pregnancy: Pregnancy is a key factor contributing to the formation of varicose and spider veins. Changes in hormone levels are one of the most important reasons women are more likely to suffer from varicose veins during pregnancy. There is an increase in progesterone, which causes the veins to relax and potentially swell more easily. There's also a significant increase in the blood volume during pregnancy, which tends to distend veins, causing valve dysfunction which leads to blood pooling in the veins. Moreover, later in pregnancy, the enlarged uterus can compress veins, causing higher vein pressure leading to dilated veins. Varicose veins that form during pregnancy may spontaneously improve or even disappear a few months after delivery. * Life-style/occupation: Those who are involved with prolonged sitting or standing in their daily activities have an increased risk of developing varicose veins. The weight of the blood continuously pressing against the closed valves causes them to fail, leading to vein distention. Other acquired causes Acquired<unk> , not related to other venous abnormalities, for example on the face and trunk, can be caused by factors such as * Cushing's syndrome * Rosacea * Blepharitis * Environmental damage such as that caused by sun or cold exposure * Age * Trauma to skin such as contusions or surgical incisions. * Radiation exposure such as that experienced during radiotherapy for the treatment of cancer, e.g., radiation proctitis * Chemotherapy * Carcinoid syndrome * Limited systemic sclerosis/scleroderma (a scleroderma sub-type) * Chronic treatment with topical corticosteroids may lead to<unk> . * Spider angiomas are a radial array of tiny arterioles that commonly occur in pregnant women and in patients with hepatic cirrhosis and are associated with palmar erythema. In men, they are related to high estrogen levels secondary to liver disease. * Tempi syndrome * Tobacco smoking * Cutaneous collagenous vasculopathy
Telangiectasia
Lymphangiectasia
Phakomatosis
Dermatothlasia
Lymphoid hyperplasia
Mastocytosis
Cutaneous lymphoid hyperplasia
Spongiosis