15618 Hereditary Hemorrhagic Telangiectasia Hht

Overview

Hereditary hemorrhagic telangiectasia (HHT) is a genetic condition that causes some blood vessels to form incorrectly. This can lead to fragile blood vessels that bleed easily and direct connections between arteries and veins (called arteriovenous malformations, or AVMs).

HHT is rare. It affects roughly 1 in 5,000 to 1 in 10,000 people worldwide, although many cases may go undiagnosed.

HHT can affect people of any age, sex, or ethnic background. Symptoms often begin in childhood or young adulthood, but some people only notice problems later in life.

Symptoms

Common symptoms

• Recurrent and often severe nosebleeds
• Small red or purple spots on the lips, tongue, mouth, fingers, or inside the nose
• Shortness of breath or a feeling of tiredness due to anemia (low red blood cells)
• Bleeding from the stomach or intestines, which may cause dark, foul-smelling stools
• A whooshing sound or a sensation of blood rushing in the chest (from lung AVMs)
• Migraine-like headaches (in some cases)

Symptoms in children

• Nosebleeds that happen often and seem to 'come out of nowhere'
• Small red spots appearing on the skin after a few years of age
• Feeding difficulties or poor weight gain in infancy (in rare cases)
• Blue-tinged lips or fingers due to low oxygen (if lung AVMs are present)

Symptoms in older adults

• More frequent and harder-to-control nosebleeds
• Anemia symptoms such as fatigue, pale skin, and dizziness
• Stomach or intestinal bleeding leading to dark stools or blood in stools
• Heart-related symptoms like liver involvement causing abdominal fullness or swelling

Causes

Main causes

• A change (mutation) in genes that help blood vessels form, most often in the ENG, ACVRL1, or SMAD4 genes
• If a parent carries the faulty gene, they have a 50% chance of passing it to each child
• Rarely, HHT may appear for the first time in a person with no family history (a new mutation)

Risk factors

• Having a parent, sibling, or other close relative with HHT
• Carrying one of the known gene mutations (detected only through genetic testing)

When to see a doctor

See a doctor urgently if:

• You have a nosebleed that won't stop after 20 minutes
• You develop symptoms of anemia, such as severe tiredness, dizziness, or looking very pale
• You notice dark, tarry stools or blood in your stool
• You have new shortness of breath or chest pain

Book a routine appointment if:

• You experience frequent nosebleeds, even if they stop on their own
• You notice small red spots on your skin or inside your nose or mouth
• You have an unexplained family history of HHT and want to know your risk

Diagnosis

Doctors use the Curaçao criteria, a set of four clinical features, to give a diagnosis: nosebleeds, visible telangiectasia, involvement of internal organs, and a family history. A diagnosis of HHT is made if a person has at least three of these features.

Tests that may be done

• A full blood count and iron levels to check for anemia (low red blood cells)
• Genetic testing to look for mutations in the ENG, ACVRL1, or SMAD4 genes (available through a genetics clinic)
• A careful examination of the nose and mouth for telangiectasia
• Imaging tests such as a CT scan of the chest or an MRI of the brain to look for AVMs
• An ultrasound of the liver to check for blood vessel malformations

What to expect at your appointment

If HHT is suspected, your doctor will likely refer you to a specialist HHT clinic. This team may include an ear-nose-throat (ENT) surgeon, a gastroenterologist, a pulmonologist, a neurologist, and a genetic counselor. They will arrange a series of tests to look for hidden AVMs and advise on monitoring.

Treatment

There is no cure for HHT, but with proper monitoring and treatment, most people can manage symptoms and reduce the risk of complications. Treatment focuses on stopping bleeding, correcting anemia, and closing or removing problematic AVMs.

Self-care at home

• Stop nosebleeds by sitting forward, pinching the soft part of the nose, and holding for 10–20 minutes
• Use a saline nasal spray or a little petroleum jelly inside the nose to keep the lining moist (avoid rubbing or blowing too hard)
• Use a cool-mist humidifier in your bedroom at night
• Avoid picking the nose or inserting anything into the nostrils
• Avoid very hot, spicy foods and drinks that can widen blood vessels (they may make nosebleeds more likely)

Medical treatments

Treatment often includes techniques such as cautery (sealing abnormal vessels with heat) or laser therapy for troublesome nosebleeds, and blood vessel embolization — a procedure where a doctor guides a tiny plug or coil into an abnormal blood vessel to block it — for AVMs in the lungs, brain, or liver. Anemia may be managed with iron replacement therapy prescribed by your care team, and, in some cases, transfusions are needed. Your doctors will choose the safest approach based on the size and location of the AVM.

When is surgery considered?

Surgery is reserved for AVMs that are very large, growing, or causing repeated bleeding or other symptoms that cannot be managed with less-invasive approaches. For example, a brain AVM that has burst may need urgent surgical treatment.

Living with this condition

Most people with HHT lead full, active lives, but they need a maintenance plan: regular appointments with an HHT specialist, careful control of nosebleeds, and prompt attention to new symptoms. Keeping a symptom diary and having a 'nosebleed kit' at home (as advised by your ENT team) can help you feel in control.

Lifestyle tips

• Inform your employers and travel insurers about your condition, especially if you have had lung AVMs
• Pace yourself with exercise: low-impact activities like walking, swimming and yoga are usually fine
• Avoid high-impact sports that involve heavy lifting or straining, as this can increase bleeding risk
• Keep your home humidified, especially in dry or air-conditioned environments
• Carry a card or bracelet that says you have HHT, in case of an emergency

Diet and exercise

Eat a balanced diet rich in iron — for example, lean red meat, leafy green vegetables, dried beans, and fortified cereals — to help prevent anemia. Keep well hydrated and avoid excessive caffeine and alcohol, which can lead to dehydration and make nosebleeds more likely.

Mental health and emotional wellbeing

Living with a chronic condition like HHT can be stressful. You may feel anxious about unexpected nosebleeds or about the future risk of internal bleeding. It's normal to need help, and counselling or a support group can make a real difference.

Prevention

HHT cannot be prevented, because it is a genetic condition. However, screening family members and having regular check-ups can help detect AVMs early and prevent serious complications like bleeding or stroke.

Vaccines

Keep your vaccinations up to date, especially those that reduce the risk of lung infections (for example, annual flu jab and pneumococcal vaccine). This helps protect you, because lung AVMs can increase the risk of brain abscess from infections.

Screening programmes

If you have a known family variant, your doctor may recommend genetic testing before you develop symptoms. Regular screening for lung AVMs (contrast echocardiogram or CT scan), brain AVMs (MRI), and liver involvement (ultrasound) is often advised every 3 to 5 years, depending on your results.

Complications

If left untreated

• Repeated bleeding can lead to severe iron-deficiency anemia and low blood counts
• Bleeding from a brain AVM can cause a stroke or permanent brain injury
• Lung AVMs can allow bacteria to pass into the bloodstream, leading to a brain abscess
• Liver AVMs may cause heart failure or liver failure when severe

Long-term outlook

With careful monitoring and modern treatments, most people with HHT have a normal or near-normal life expectancy. The key is to have a specialist team who screens for hidden AVMs and treats them before they bleed. Many people live active lives, manage nosebleeds well, and have no major disability.

Find support

International organisations

• Cure HHT (HHT Foundation International) ↗

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