Hereditary hemorrhagic telangiectasia (HHT), also known as Osler–Weber–Rendu disease and Osler–Weber–Rendu syndrome, is an autosomal dominant genetic disorder that leads to abnormal blood vessel formation in the skin, mucous membranes, and often in organs such as the lungs, liver, and brain, It may lead to nosebleeds, acute and chronic digestive tract bleeding, and various problems due to the involvement of other organs. Treatment focuses on reducing bleeding from blood vessel lesions, and sometimes surgery or other targeted interventions to remove arteriovenous malformations in organs. Chronic bleeding often requires iron supplements and sometimes blood transfusions. HHT is transmitted in an autosomal dominant fashion, and occurs in one in 5,000 people.
Telangiectasia (small vascular malformations) may occur in the skin and mucosal linings of the nose and gastrointestinal tract. The most common problem is nosebleeds (epistaxis), which happen frequently from childhood and affect about 90–95% of people with HHT. Lesions on the skin and in the mouth bleed less often but may be considered cosmetically displeasing; they affect about 80%.The skin lesions characteristically occur on the lips, the nose and the fingers, and on the skin of the face in sun-exposed areas. They appear suddenly, with the number increasing over time Treatment of HHT is symptomatic (it deals with the symptoms rather than the disease itself), as there is no therapy that stops the development of telangiectasias and AVMs directly.
Furthermore, some treatments are applied to prevent the development of common complications. Chronic nosebleeds and digestive tract bleeding can both lead to anemia; if the bleeding itself cannot be completely stopped, the anemia requires treatment with iron supplements. Those who cannot tolerate iron tablets or solutions may require administration of intravenous iron sucrose, and blood transfusion if the anemia is causing severe symptoms that warrant rapid improvement of the blood count. Most treatments used in HHT have been described in adults, and the experience in treating children is more limited. Women with HHT who get pregnant are at an increased risk of complications, and are observed closely, although the absolute risk is still low (1%)