Telangiectasia is a skin condition characterized by the permanent dilation of small blood vessels, frequently forming a star shape on the skin. It is benign in the majority of cases, but can be associated with several diseases and be a symptom of a serious underlying disease, such as ataxia-telangiectasia or hereditary hemorrhagic telangiectasia. Hereditary hemorrhagic telangiectasia (HHT), also called Rendu-Osler-Weber disease, is a rare genetic disorder with a prevalence of 1 in 5 to 000 in 1, (8) which causes telangiectasias that are not cutaneous but appearing in vital organs, such as the liver. They can burst, cause massive bleeding and be life-threatening. Ataxia-telangiectasia is an even rarer inherited disease, affecting 000 in 1 children (1). With telangiectasias, it associates serious neurological disorders resulting in a deficit in coordination of movements (ataxia).

The pathology affects intradermal venules measuring less than 1 mm in diameter. The dilation of the venules causes very fine lines of red, blue and purple to appear on the skin, forming star patterns, stellate angiomas. Telangiectasias are likely to form on the skin and mucous membranes anywhere on the body, but they most commonly appear where the skin is most exposed to sunlight and air: the nose, cheeks, lips, whites of eyes and fingers.

The exact cause of telangiectasia is not yet known. They could be genetic, environmental, or a combination of both. Chronic overexposure of the skin to the sun or extreme temperatures is the cause of most cases. Hereditary hemorrhagic telangiectasia and ataxia-telangiectasia have a genetic origin. The first is due to the mutation of the ACVRL and ENG genes and the second to the mutation of the ATM gene.

People who work outdoors or on the contrary seated all day, pregnant women, the elderly, people undergoing corticosteroid therapy, suffering from alcoholism or diseases such as rosacea, scleroderma, dermatomyositis, or lupus erythematosus disseminated, are more exposed than others to telangiectasia.

Benign telangiectasias are treated for cosmetic reasons. Sclerotherapy consists of injecting a sclerosing product with a very fine needle into telangiectasias located on the legs. Laser and radiofrequency therapy involves burning the dilated venules. Finally, surgical removal of dilated blood vessels can be used.