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Health condition · Clinically reviewed

Hereditary haemorrhagic telangiectasia, the vascular condition behind unexplained nosebleeds and paradoxical stroke.

One in 5,000 people carry a gene for HHT - and most don't know. A well-run UK care plan turns a lifetime of surprises into a predictable programme of screening, embolisation and modern anti-VEGF therapy.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against the international HHT guidelines, NHS specialist commissioning standards and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including systemic bevacizumab, pulmonary AVM embolisation and cascade genetic testing.

Key facts

HHT at a glance.

The essentials, in plain English - what HHT is, which genes drive it, and where UK care sits today.

  • What it is

    Hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu) - an autosomal dominant vascular dysplasia producing telangiectasia and arteriovenous malformations.

  • How common

    Around 1 in 5,000 people in the UK - often under-recognised, with diagnosis frequently delayed by decades.

  • The genes

    ENG (HHT1, endoglin - pulmonary bias), ACVRL1 (HHT2, ALK1 - hepatic bias), SMAD4 (juvenile polyposis-HHT overlap) and GDF2.

  • Curaçao criteria

    Epistaxis, telangiectasia, visceral AVMs and a first-degree relative - three or more makes a definite diagnosis.

  • Why it matters

    Pulmonary AVMs can cause paradoxical stroke or brain abscess; hepatic AVMs can drive high-output cardiac failure; nosebleeds sap quality of life.

  • Where care sits

    Specialist commissioned HHT centres in the UK (including Hammersmith and Cambridge) coordinate screening, embolisation and systemic therapy.

Why this guide matters

An under-diagnosed condition, with a well-defined care pathway.

HHT is not rare - it is under-recognised. The three points below shape the whole page and the way UK specialist commissioned centres approach families with the condition.

  • Nosebleeds are the tip of the iceberg

    The visible problem is epistaxis; the hidden problems are pulmonary, hepatic, cerebral and GI AVMs that need proactive screening.

  • Screening prevents catastrophes

    Contrast echocardiography, CT thorax and hepatic Doppler let us find and treat AVMs before stroke, abscess or cardiac failure.

  • Systemic bevacizumab is practice-changing

    Anti-VEGF therapy has reshaped care for refractory epistaxis, hepatic AVM burden and GI bleeding in specialist commissioned centres.

How the diagnosis is made

From family story to a structured screening programme.

The pathway a UK GP, ENT surgeon and HHT centre will normally follow, in order - so you know what to expect and why.

  1. 01

    Recognising

    History, family tree and Curaçao

    A careful account of nosebleeds, visible telangiectasia and relatives with HHT - scored against the Curaçao criteria.

  2. 02

    Recognising

    Full examination

    Looking for telangiectasia on lips, tongue, fingers and nasal mucosa - the mucocutaneous signature of HHT.

  3. 03

    Recognising

    Iron studies and FBC

    Iron-deficiency anaemia from epistaxis or GI bleeding is common and often the first laboratory clue.

  4. 04

    Confirming

    Genetic testing

    ENG, ACVRL1, SMAD4 and GDF2 sequencing through specialist commissioned services - with cascade testing for relatives.

  5. 05

    Confirming

    Pulmonary AVM screening

    Contrast (bubble) echocardiogram is the primary screen; CT thorax and pulmonary vascular review follow if positive.

  6. 06

    Confirming

    Hepatic and cerebral imaging

    Doppler ultrasound of the liver, plus MRI brain in selected patients - especially before pregnancy or symptomatic disease.

  7. 07

    Coordinating

    HHT centre MDT

    Specialist commissioned HHT centres coordinate the plan - screening intervals, embolisation, systemic therapy and family cascade.

Typical timeline: from first suspicion to a settled screening plan in a matter of months.

Symptoms

What HHT actually looks like.

Nosebleeds and small red spots on the lips are the classic story - but the visceral AVMs behind the scenes are what drive the medical risk.

  • Recurrent spontaneous nosebleeds

    The hallmark symptom - often daily, disruptive and the leading cause of iron deficiency in HHT.

  • Mucocutaneous telangiectasia

    Small red spots on the lips, tongue, palate, nasal mucosa and fingertips - blanch on pressure.

  • Pulmonary AVM signs

    Breathlessness, low oxygen saturations, cyanosis or unexplained stroke and brain abscess in a young person.

  • Hepatic AVM signs

    High-output cardiac failure, right-upper-quadrant discomfort, portal hypertension or biliary complications.

  • Cerebral AVM signs

    Seizures, focal neurology or intracerebral haemorrhage - rarer, but a reason for brain MRI in selected patients.

  • GI bleeding and iron deficiency

    Chronic occult loss from gastric or small-bowel telangiectasia - often the driver of transfusion dependence in older adults.

  • Family history

    A first-degree relative with epistaxis, telangiectasia or a visceral AVM - autosomal dominant, so each child has a 50% risk.

  • Red flag - neurological event

    Stroke, transient ischaemic attack, seizure or brain abscess in an HHT patient warrants urgent pulmonary AVM assessment.

Treatment

How HHT is managed in the UK.

A layered plan - daily mucosal care, targeted procedures for AVMs and, where needed, systemic anti-VEGF therapy through a specialist commissioned centre.

  • Nasal hygiene and lubrication

    Humidification, saline sprays and lubricants (including Nozovent-style devices) reduce mucosal trauma and daily bleeding.

  • Tranexamic acid

    Topical or oral - reduces epistaxis frequency and severity as a first-line antifibrinolytic.

  • Nasal bevacizumab

    Submucosal or topical anti-VEGF for troublesome epistaxis - delivered in specialist ENT services.

  • Endonasal laser and septodermoplasty

    Coagulation of individual telangiectasia and skin grafting of the septum - staged, specialist ENT procedures.

  • Young procedure (nasal closure)

    A last-line surgical option for severe refractory epistaxis - closes the nostrils to end mucosal trauma.

  • Pulmonary AVM embolisation

    Coil or plug embolisation by interventional radiology for feeding arteries above 2 to 3 mm - reduces stroke and abscess risk.

  • Systemic bevacizumab

    Subcutaneous or intravenous anti-VEGF - practice-changing in refractory epistaxis, hepatic AVM and GI bleeding.

  • Iron replacement

    Oral iron first, then intravenous iron and transfusion as needed - a mainstay of long-term HHT care.

What this guide is based on

The sources behind every claim on this page.

International HHT guidelines, UK specialist commissioning standards and patient organisations, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or HHT centre team knows your history and can tell you which parts of this page apply to you. If in doubt, get seen.

  • Second International Guidelines for the Diagnosis and Management of HHT (Ann Intern Med, 2020).

  • UK HHT specialist commissioned service standards (NHS England).

  • British Society for Haematology and NICE guidance on iron-deficiency anaemia.

  • HHT UK (Telangiectasia Self Help Group) patient information.

Red flags

When HHT needs urgent attention.

Most HHT care runs on a calm, planned rhythm. These are the situations that don't - and where an HHT centre or acute team needs to be involved quickly.

  • Stroke or transient ischaemic attack

    A cerebrovascular event in a person with HHT is a pulmonary AVM until proven otherwise - urgent cross-sectional imaging and interventional radiology review.

  • Brain abscess

    Paradoxical seeding through a pulmonary AVM - an infection-medicine and neurosurgical emergency, with rapid embolisation once stabilised.

  • Sudden breathlessness or hypoxaemia

    A large or ruptured pulmonary AVM can cause haemothorax or profound desaturation - a resuscitation-level presentation.

  • Massive epistaxis

    Uncontrolled bleeding needs A&E assessment, airway protection, packing and rapid ENT input.

  • Melaena or symptomatic anaemia

    Chronic GI blood loss can decompensate acutely - urgent endoscopy and transfusion, then long-term iron and bevacizumab planning.

  • Pregnancy without prior screening

    Undiagnosed pulmonary AVMs in pregnancy can be catastrophic - screening and embolisation before conception where possible.

  • High-output cardiac failure

    Progressive breathlessness, ankle swelling and fatigue in HHT2 patients - a signal of hepatic AVM burden needing specialist review.

  • New neurological symptoms

    Focal weakness, seizures or headache with vomiting need urgent brain imaging - cerebral AVMs are rarer but treatable.

  • SMAD4-positive patients

    Juvenile polyposis-HHT overlap - lifelong gastrointestinal surveillance is added to the standard HHT programme.

Living with it

A lifelong condition, with a predictable rhythm.

Four things that make the biggest difference day to day - protecting the nose, staying on top of iron, keeping screening intervals and telling your family.

A quiet reminder

A named HHT centre is worth its weight in gold.

Once you are known to a specialist commissioned service, everything else - GP, ENT, radiology - lines up around a shared plan.

  1. 01 Routine

    Protect the nasal mucosa daily

    Humidified air, saline sprays and gentle lubricants - small habits that cut daily bleeding more than any device.

  2. 02 Iron

    Stay on top of iron

    Regular ferritin checks, oral iron and - when needed - intravenous iron keep energy, exercise tolerance and cognition steady.

  3. 03 Screening

    Keep your screening intervals

    Pulmonary and hepatic screening is not a one-off - lesions can grow, and pregnancy or new symptoms reset the clock.

  4. 04 Family

    Talk to your relatives

    First-degree relatives have a 50% risk - cascade genetic testing and screening in an HHT centre changes their trajectory.

Frequently asked

Everything we get asked about HHT.

Quick answers on diagnosis, screening, pulmonary AVMs, bevacizumab and family testing.

  • What is hereditary haemorrhagic telangiectasia?

    HHT (also called Osler-Weber-Rendu syndrome) is an autosomal dominant vascular disorder producing small telangiectasia on skin and mucosa, and larger arteriovenous malformations in the lungs, liver, brain and gut. It affects roughly 1 in 5,000 people in the UK.

  • How is HHT diagnosed?

    Using the Curaçao criteria - recurrent spontaneous nosebleeds, mucocutaneous telangiectasia, a visceral AVM and a first-degree relative with HHT. Three or more criteria give a definite diagnosis; genetic testing of ENG, ACVRL1, SMAD4 and GDF2 confirms it and enables cascade testing of relatives.

  • Why are pulmonary AVMs so important?

    They let blood bypass the lung filter, so small clots or bacteria can travel straight to the brain - causing paradoxical stroke or brain abscess even in young, otherwise well people. Screening with a bubble echocardiogram and embolisation of feeding arteries above 2 to 3 mm prevents most of these events.

  • Can bevacizumab really change HHT?

    Yes - systemic bevacizumab (an anti-VEGF antibody) has been practice-changing for refractory epistaxis, hepatic AVM-driven cardiac failure and gastrointestinal bleeding. It is prescribed through specialist commissioned HHT centres with careful monitoring.

  • What is the pregnancy risk in HHT?

    Undiagnosed or untreated pulmonary AVMs carry a real risk of catastrophic bleeding or paradoxical embolism in pregnancy. Where possible, screening and embolisation are completed before conception, with high-risk obstetric and HHT-centre input during pregnancy.

  • What should my relatives do?

    First-degree relatives have a 50% chance of inheriting HHT. They should be offered cascade genetic testing (when the family variant is known) and screening in a specialist commissioned HHT centre - it is much easier to prevent problems than to treat them once they have happened.

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