Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia, or HHT, is an inherited disorder that affects the structure of blood vessels. Although recurrent nosebleeds are the most common sign, abnormal vessel connections may also develop in the lungs, brain, liver, and digestive system. For that reason, diagnosis and screening are important not only for symptom control but also for preventing serious complications.

What is hereditary hemorrhagic telangiectasia?

Hereditary hemorrhagic telangiectasia is a genetic vascular disorder that affects how blood vessels develop. In this disease, normal small-vessel networks are partly replaced by more fragile and abnormal vessel connections. As a result, telangiectasias may appear on the skin and mucous membranes, while arteriovenous malformations can develop in deeper organs. HHT is often first noticed in childhood or young adulthood because of repeated nosebleeds. Even within the same family, however, the severity can vary from person to person. In some individuals symptoms are mild, while in others more serious risks arise because of lung, brain, or liver involvement. ^[1][2]

What are the symptoms?

The most common symptom is spontaneous nosebleeds that tend to recur. Small red-purple vessel markings may also be seen on the lips, tongue, face, inside the mouth, or fingertips. Chronic bleeding can eventually cause iron deficiency and anemia, leading to fatigue, palpitations, and shortness of breath. In some people, abnormal vessel connections in the lungs can result in breathlessness, low oxygen levels, or more serious outcomes such as stroke and brain abscess. Brain vessel involvement may present with headaches, seizures, or neurological symptoms. For this reason, what appears to be “just nosebleeds” can sometimes require a much broader evaluation. ^[1][2][3]

What causes it and how does it run in families?

HHT is an inherited disease and in most cases shows an autosomal dominant pattern. This means there is a meaningful chance that a parent carrying the condition can pass it to a child. Changes in the relevant genes affect the formation and repair of vessel walls, creating a tendency toward fragile blood vessels. Family history is therefore very valuable in diagnosis, although earlier generations may never have been formally diagnosed. Because nosebleeds are common in the general population, families may initially think HHT is an ordinary problem. However, unexplained iron deficiency, pulmonary AVMs, stroke history, brain abscess, or very frequent nosebleeds in the same family should raise suspicion for HHT. ^[1][2]

How is it diagnosed?

Diagnosis is made by evaluating clinical findings, family history, and when needed genetic testing together. Physicians consider frequent nosebleeds, typical telangiectasias, AVMs in internal organs, and the presence of HHT in first-degree relatives. Imaging tests may be ordered to look for lung, brain, or liver involvement. The main goal is not only to confirm the diagnosis but also to detect silent vascular abnormalities that carry a risk of serious complications. Pulmonary AVMs in particular may exist without causing obvious symptoms. For this reason, even people whose symptoms are limited should still be included in a planned screening and follow-up program once HHT is diagnosed. ^[1][2][3]

How is treatment planned?

Treatment depends on which organs are involved and how heavy the bleeding burden is. For nosebleeds, moisturizing measures, local procedures, and in some cases laser or other ear-nose-throat interventions may be used. In people with frequent bleeding and iron deficiency, iron treatment and, when necessary, management of anemia are important. When internal organs such as the lungs are involved, treatment planned by interventional radiology or other relevant specialties may be needed. In some severe bleeding cases, medications that suppress abnormal vessel growth may also be considered, but this decision should always be made by a specialist. The goal of treatment is not only to reduce bleeding but also to prevent consequences such as stroke, abscesses, and chronic anemia. ^[2][3]

Complications and emergency warnings

The risk of complications in HHT depends on which organs are affected. Recurrent nose or gastrointestinal bleeding can lead to iron deficiency anemia. Pulmonary AVMs can increase the risk of low oxygen levels, stroke, or brain abscess. Brain vascular malformations may rarely present with bleeding or seizures. For this reason, severe uncontrolled bleeding, sudden neurological symptoms, a new seizure, marked shortness of breath, or a sudden change in consciousness require urgent evaluation. It is important for a person with HHT to know these possibilities, but it is also important to remember that not every symptom means a major complication. Regular follow-up is the safest way to separate higher-risk situations from less dangerous ones. ^[1][2][3]

Daily life, follow-up, and family screening

In people living with HHT, regular follow-up is critical for long-term safety. Reducing dryness of the nasal lining, recognizing bleeding triggers, and having periodic checks for iron deficiency can all be helpful. Blood thinners or other medicines that may increase bleeding should always be reviewed with a physician. Family members should also be assessed for risk because silent AVMs may exist in relatives who have not been diagnosed. In people planning pregnancy, evaluation beforehand is especially important for possible lung or brain vascular involvement. This content does not replace personal medical advice. When recurrent nosebleeds occur together with a family history, specialist evaluation should not be delayed. ^[1][2][3]

Why is screening of internal organs so important?

The real clinical importance of HHT lies not only in visible nosebleeds but also in detecting silent vascular abnormalities in internal organs. Pulmonary AVMs in particular may be present without causing any symptoms, yet still be associated with serious outcomes such as stroke, brain abscess, or low oxygen levels. Brain vascular malformations can also remain silent. For that reason, screening recommendations remain important even when the symptom burden seems small. Organ screening is performed not to frighten patients but to identify high-risk situations early. Regular and planned follow-up is one of the cornerstones of HHT management. ^[1][2][3]

Why is extra caution needed during pregnancy and invasive procedures?

For people with HHT, evaluation before pregnancy or major procedures is important. Blood volume changes during pregnancy can make some existing vascular abnormalities more clinically apparent. Likewise, before surgery or invasive procedures, knowing whether a person has a pulmonary AVM or similar condition is important for safety. This does not mean every patient is at high risk, but it is not appropriate to move forward without understanding the individual risk profile. HHT patients who are planning a family or an interventional procedure should seek advice from the team following them beforehand. ^[2][3]

When symptoms are long-lasting, rapidly worsening, or accompanied by emergency warning signs, personal medical evaluation is necessary; this content does not replace diagnosis or treatment. ^[1][2]

FAQ

Is HHT just a nosebleed disease?

No. Nosebleeds are the most common symptom, but vascular abnormalities can also develop in the lungs, brain, liver, and digestive system. ^[1][2]

Is HHT inherited?

Yes. Most cases show familial transmission, so once the diagnosis is made it is important to ask about family history and evaluate close relatives. ^[1]

Can HHT cause anemia?

Yes. Recurrent nose or gastrointestinal bleeding can lead to iron deficiency and anemia. ^[2][3]

Which symptoms are emergencies?

Severe uncontrolled bleeding, sudden neurological symptoms, a new seizure, marked shortness of breath, or a change in consciousness require urgent evaluation. ^[2][3]

Does treatment cure it completely?

Treatment is usually aimed at controlling symptoms and complications. Depending on the organs involved, different interventions and follow-up may be required. ^[2][3]