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# Hereditary haemorrhagic telangiectasia (Osler–Weber–Rendu)

An inherited blood vessel disorder that causes repeated nosebleeds, red spots on lips and fingers, and abnormal vessels in the lungs, brain and liver.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Nasal septum](https://durgical.com/en/anatomy/nasal-septum/)
- [Liver](https://durgical.com/en/anatomy/liver/)
- [Nasal cavity](https://durgical.com/en/anatomy/nasal-cavity/)
- [Tongue](https://durgical.com/en/anatomy/tongue/)
- [Pulmonary arteries](https://durgical.com/en/anatomy/right-pulmonary-artery/)
- [Pulmonary veins](https://durgical.com/en/anatomy/pulmonary-veins/)
- [Hepatic veins](https://durgical.com/en/anatomy/hepatic-veins/)
- [Portal vein](https://durgical.com/en/anatomy/hepatic-portal-vein/)
- [Stomach](https://durgical.com/en/anatomy/stomach/)
- [Duodenum](https://durgical.com/en/anatomy/duodenum/)

## Why it happens

- [Mendelian inheritance: autosomal dominant, recessive and X-linked](https://durgical.com/en/general-pathology/mendelian-inheritance-autosomal-dominant-recessive-and-x-linked/)
- [Hemorrhage: petechiae, purpura, ecchymosis, hematoma, and what blood loss does](https://durgical.com/en/general-pathology/hemorrhage-petechiae-purpura-ecchymosis-hematoma-and-what-blood-loss-does/)
- [Blood vessels: artery, vein and capillary layers](https://durgical.com/en/histology/blood-vessels-artery-vein-and-capillary-layers/)

## What it is

An autosomal dominant disorder of blood vessel development in which arteries connect directly to veins without capillaries. Small connections in the [skin](https://durgical.com/en/anatomy/skin/) and mucosa form telangiectasias that bleed easily; larger arteriovenous malformations (AVMs) occur in the lungs, brain, liver and gut.

## Who gets it

It affects roughly 1 in 5,000 to 10,000 people in all ethnic groups, men and women equally. Nosebleeds usually begin in childhood, skin telangiectasias appear by adulthood, and many patients go years without a diagnosis because nosebleeds are so common in the general population. Latin American series describe the same features; in Colombia it is often first recognised in otorhinolaryngology clinics.

## Causes

- Pathogenic variants in ENG (HHT type 1) or ACVRL1/ALK1 (HHT type 2)
- SMAD4 variants cause combined juvenile polyposis and HHT
- GDF2 and other rarer genes
- Autosomal dominant inheritance: each child of an affected parent has a 50% chance

## Risk factors

- A parent, sibling or child with HHT
- Dry air, nasal trauma and anticoagulant or antiplatelet drugs worsen bleeding
- Pregnancy raises the risk of complications from lung AVMs

## Pathophysiology

The affected genes encode parts of the TGF-beta / BMP9 signalling pathway in endothelial cells, which controls how new vessels mature. With half the normal signal, vessels exposed to a second trigger (injury, inflammation) grow into dilated, thin-walled direct artery-to-vein channels. In the nose and gut these rupture with minor trauma. Lung AVMs form a right-to-left shunt that lets clots and bacteria bypass the lung filter, causing stroke and brain abscess, and they lower oxygen saturation. Liver AVMs can cause high-output heart failure, portal hypertension or biliary ischaemia.

## Classification

- HHT1 (ENG): more lung and brain AVMs, earlier symptoms
- HHT2 (ACVRL1): more liver AVMs
- Juvenile polyposis–HHT overlap (SMAD4)
- Curaçao clinical criteria: definite with 3 or 4, possible with 2 of recurrent spontaneous epistaxis, mucocutaneous telangiectasias, visceral AVMs and a first-degree relative with HHT

## Symptoms and signs

- Recurrent spontaneous nosebleeds, often from childhood and the most common symptom
- Small red or purple spots on the lips, tongue, face, fingertips and nasal mucosa that blanch with pressure
- Tiredness and pallor from iron-deficiency anaemia
- Black stools or gut bleeding, mostly after age 50
- Breathlessness, cyanosis or clubbing from lung AVMs
- Headache or seizures from brain AVMs

## Red flags

- Sudden weakness, speech trouble or other stroke signs (paradoxical embolism through a lung AVM)
- Fever with headache and focal signs (brain abscess)
- Haemoptysis or haemothorax, especially in pregnancy
- Severe headache or seizure (bleeding brain AVM)
- Nosebleed that will not stop with haemodynamic instability

## Diagnosis

**Clinical**
Based on the Curaçao criteria and a careful family history; examine lips, [tongue](https://durgical.com/en/anatomy/tongue/), palate, fingers and nasal mucosa. Once suspected, patients are screened for visceral AVMs even without symptoms.

**Tests**
Full blood count and ferritin for iron-deficiency anaemia; pulse oximetry; genetic testing for ENG, ACVRL1 and SMAD4 confirms the diagnosis and allows family screening. Endoscopy for gut bleeding, and colonoscopy for polyps in SMAD4 carriers.

**Imaging**
Transthoracic contrast (bubble) echocardiography to screen for lung AVMs, followed by [chest](https://durgical.com/en/anatomy/region/chest/) CT when positive; brain MRI to screen for cerebral AVMs; Doppler ultrasound or CT of the [liver](https://durgical.com/en/anatomy/liver/) when liver AVMs are suspected.

## Differential diagnosis

- Common anterior epistaxis without systemic disease
- Bleeding disorders such as von Willebrand disease
- CREST/limited systemic sclerosis (telangiectasias)
- Spider angiomas of liver disease
- Isolated angiodysplasia of the gut
- Sporadic cerebral or pulmonary AVM

## Goal of treatment

Reduce nosebleeds and gut bleeding, correct iron deficiency, and find and treat lung and brain AVMs before they cause stroke, abscess or haemorrhage.

## Treatment

**Conservative**
Nasal moisturisers, saline and humidification to protect the mucosa; gentle compression for acute nosebleeds and avoiding nasal packing that tears vessels when possible.

**Medical**
Iron replacement (oral or intravenous) and transfusion for anaemia; antifibrinolytics such as tranexamic acid, and anti-angiogenic therapy (bevacizumab) or other agents for severe bleeding in specialist centres.

**Procedure**
Laser or other ablation of nasal and gut telangiectasias; septodermoplasty or nasal closure for refractory epistaxis.

**Procedure**
Transcatheter embolisation of lung AVMs with a feeding artery large enough to treat; brain AVMs are managed by neurosurgery, embolisation or radiosurgery depending on risk.

**Follow-up**
Antibiotic prophylaxis before dental and other procedures and air filters on intravenous lines when lung AVMs are present; repeat screening and family testing; nursing care includes teaching first aid for nosebleeds and monitoring haemoglobin.

## Complications

- Chronic iron-deficiency anaemia and transfusion dependence
- Ischaemic stroke and brain abscess from paradoxical embolism
- Brain haemorrhage
- Hypoxaemia and haemothorax from lung AVMs
- High-output heart failure, portal hypertension and pulmonary hypertension from liver AVMs
- Colorectal cancer risk in SMAD4 juvenile polyposis

## Prognosis

Life expectancy is close to normal when visceral AVMs are found and treated early, but quality of life is often limited by bleeding and anaemia. Untreated lung AVMs carry a substantial risk of stroke and brain abscess.

## Prevention

- Screening of affected people and their relatives for lung and brain AVMs
- Antibiotic prophylaxis before dental procedures when lung AVMs are present
- Genetic counselling for families

## Test yourself

Think of the answer, then tap the question to see it.

## What is the inheritance pattern of hereditary haemorrhagic telangiectasia?

Autosomal dominant (ENG, ACVRL1, SMAD4).

## What is the most common symptom of HHT?

Recurrent spontaneous nosebleeds (epistaxis).

## Why do lung AVMs in HHT cause stroke and brain abscess?

They form a right-to-left shunt that lets clots and bacteria bypass the lung capillaries and reach the brain.

## What test screens for pulmonary AVMs in HHT?

Transthoracic contrast (bubble) echocardiography, confirmed by chest CT.

## What are the four Curaçao criteria?

Recurrent spontaneous epistaxis, mucocutaneous telangiectasias, visceral AVMs and a first-degree relative with HHT.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/conditions/hereditary-haemorrhagic-telangiectasia/)

## Related conditions

- [Epistaxis (nosebleed)](https://durgical.com/en/conditions/epistaxis/)
- [Brain arteriovenous malformation](https://durgical.com/en/conditions/brain-arteriovenous-malformation/)
- [Intracerebral haemorrhage](https://durgical.com/en/conditions/intracerebral-haemorrhage/)
- [Brain abscess](https://durgical.com/en/conditions/brain-abscess/)
- [Ischaemic stroke](https://durgical.com/en/conditions/ischaemic-stroke/)
- [Iron deficiency anaemia](https://durgical.com/en/conditions/iron-deficiency-anaemia/)
- [Upper gastrointestinal bleeding](https://durgical.com/en/conditions/upper-gastrointestinal-bleeding/)
- [Heart failure](https://durgical.com/en/conditions/heart-failure/)
- [Pulmonary hypertension and cor pulmonale](https://durgical.com/en/conditions/pulmonary-hypertension-and-cor-pulmonale/)
- [Portal hypertension](https://durgical.com/en/conditions/portal-hypertension/)
- [Colorectal polyps and hereditary polyposis syndromes (FAP, Lynch)](https://durgical.com/en/conditions/colorectal-polyps-and-hereditary-polyposis-syndromes/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Hereditary hemorrhagic telangiectasia](https://medlineplus.gov/genetics/condition/hereditary-hemorrhagic-telangiectasia/) (MedlinePlus Genetics (U.S. National Library of Medicine), 2020); [About Hereditary Hemorrhagic Telangiectasia (HHT)](https://www.cdc.gov/hht/about/index.html) (Centers for Disease Control and Prevention (CDC), 2024).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/conditions/hereditary-haemorrhagic-telangiectasia/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/hereditary-haemorrhagic-telangiectasia/