Telangiectasia

Telangiectasias are small dilated blood vessels near the surface of the skin or mucous membranes, measuring between 0.5 and 1 millimeter in diameter. They can develop anywhere on the body but are commonly seen on the face around the nose, cheeks, and chin. They can also develop on the legs, specifically on the upper thigh, below the knee joint, and around the ankles.

Some telangiectasia are due to developmental abnormalities that can closely mimic the behaviour of benign vascular neoplasms. They may be composed of abnormal aggregations of arterioles, capillaries, or venules. Because telangiectasias are vascular lesions, they blanch when tested with diascopy.

Causes
The causes of telangiectasia can be divided into congenital and acquired factors.

Congenital causes
Goldman states that "numerous inherited or congenital conditions display cutaneous telangiectasia". These include;
 * Naevus flammeus (port-wine stain)
 * Klippel-Trenaunay syndrome
 * Maffucci's syndrome (multiple endochondromas & hemangiomas)
 * Hereditary hemorrhagic telangiectasia (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 mental retardation.

Venous hypertension
Telangiectasia in the legs is often related to the presence of venous hypertension within underlying varicose veins. Flow abnormalities within the medium sized veins of the leg (reticular veins) can also lead to the development of telangiectasia. Factors that predispose to the development of varicose and telangiectatic leg veins include
 * Age: The development of spider veins may occur at any age but 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. 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.
 * Lifestyle/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 telangiectasia, not related to other venous abnormalities, for example on the face and trunk, can be caused by factors such as
 * 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 (a variant of scleroderma)
 * Chronic treatment with topical corticosteroids may lead to telangiectasia.
 * 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.

Treatment
Sclerotherapy is the "gold standard" and is preferred over laser for eliminating telangiectasiae and smaller varicose leg veins. A sclerosant medication is injected into the diseased vein so it hardens and eventually shrinks away. Recent evidence with foam sclerotherapy shows that the foam containing the irritating sclerosant quickly appears in the patients heart and lungs, and then in some cases travels through a patent foramen ovale to the brain. This has led to concerns about the safety of sclerotherapy for telangectasias and spider veins. In some cases stroke and transient ischemic attacks have occurred after sclerotherapy. Varicose veins and reticular leg veins, if present, must be treated prior to any treatment of the telangiectasia. Varicose veins can be treated with foam sclerotherapy, endovenous laser treatment, radiofrequency ablation or open surgery. The biggest risk, however, seems to occur with sclerotherapy, especially in terms of systemic risk of DVT, pulmonary embolism, and stroke.

Another issue that arises with the use of sclerotherapy to treat spider veins is staining, shadowing, telangetatic matting and ulceration. In addition, incompleteness of therapy is common, requiring multiple treatment sessions.

Telangiectasias on the face are often treated with a laser. Laser therapy uses a light beam that is pulsed onto the veins in order to seal them off, causing them to dissolve. These light-based treatments require adequate heating of the veins. These treatments can result in the destruction of sweat glands, the risk increases with the number of treatments.