Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant mucocutaneous and visceral fibrovascular dysplasia in which telangiectasia, arteriovenous malformations and aneurysms may be widely distributed throughout the cardiovascular system. It is usually recognized as a "triad" of telangiectasia, recurrent epistaxis and a family history of the disorder. However, owing to variability in location, type and number of randomly distributed vascular malformations, affected persons may be asymptomatic or present at any age with a wide range of clinical manifestations. Legg in 1876 first reported the case of a patient with telangiectasia on the face, epistaxis and painful swollen joints. Rendu, Osler and Weber later described other cases of this disorder with recurrent epistaxis, which acquired the eponym Osler-Weber-Rendu disease.
The underlying pathologic abnormality appears to be a combination of an insufficient smooth muscle contractile element, endothelial cell junction defects and perivascular connective tissue weakness. In addition, an increased tissue plasminogen activator in the abnormal endothelium may impair thrombus formation once bleeding begins. An association of disseminated intravascular coagulation, factor XI deficiency and type II Von Willebrand's syndrome with OWR disease has been reported. HHT occur in all races with an estimated frequency of 1-2 per 100,000. Blood group O occurs significantly more often in HHT patients than in the comparative background population. Although it is known as autosomal dominant, in 20% of the cases there is no family history of telangiectasia or recurrent bleeding.
Telangectasia on face, lips, tongue, hands ( picture below) and on nasal septum. The nasal lesions are responsible for recurrent epistaxis and are sometimes treated by excising the affected nasal mucosa and covering the defect with a skin graft. This procedure is called septal dermoplasty.
Osler-Weber telangectasias of the tongue.and fingers and hard palate. This patient also suffers from profuse nosebleeds.