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Signs & Symptoms

Knowing signs and symptoms of HHT leads to a faster diagnosis.

There are many times that a person with HHT may appear to have no symptoms at all.

Some people with HHT may show almost no signs of the disease until they are in their 40s or 50s. However, just because a person reaches 50 without symptoms does not mean they are not affected with HHT. It is common for people with HHT to have symptoms that can only be detected by a doctor who is familiar with HHT. HHT affects everyone differently, and will even affect members in the same family very differently.

The average delay in diagnosis of HHT is

95% of people with HHT will develop symptoms over their lifetime.

It often takes a severe event for someone to realize the underlying cause is HHT. Once a diagnosis is made, a person with HHT can be properly screened and treated. This can help to avoid severe events due to HHT from occurring and allows HHT patients to live full lives without worrying about their disease.

HHT is underdiagnosed; only one out of every 10 affected individuals are diagnosed.

Some refer to HHT as the "great masquerader," as the symptoms can disguise as anemia, migraine, asthma, stroke, congestive heart failure, or liver cirrhosis. This often results in years of misdiagnoses.

HHT Diagnosis and Misdiagnosis Fact Sheet

Physician Fact Sheet

Signs & Symptoms

Recurring nosebleeds affect about 90% of people with HHT and is the most common symptom of the disease.

Nosebleeds are often the earliest symptom of HHT. Since HHT is hereditary disease, nosebleeds run in HHT families. While the most common symptom of HHT is nosebleeds, HHT is a very complex disease that affects several major organs of the body (including the brain, lungs, liver, and heart). There are many screening guidelines for those who are diagnosed or think they might have HHT.

HHT causes malformed blood vessels that results in vascular abnormalities that can lead to bleeding and complications including, but not limited to:

  • Nosebleeds
  • Shortness of breath, exercise intolerance, fatigue
  • Iron deficiency and anemia
  • Migraine headaches
  • Seizures
  • Stroke
  • GI bleeding
  • Back pain, swelling, or numbness
  • Heart failure

These symptoms or events can occur in people without HHT, but a family history of these symptoms could indicate HHT.

The two types of vascular abnormalities that characterize HHT are Telangiectasia and Arteriovenous Malformations (AVMs)


Telangiectasia is a condition that consists of small vascular malformations that appear as 1-2 mm red spots on the surface of the skin, the lining of the nose and the lining of the intestinal tract.


Most people with HHT have telangiectasia on the skin inside their nose, which cause nosebleeds (epistaxis) when ruptured.

  • HHT is hereditary, so nosebleeds often run in families that are affected by this disease.
  • Recurring nosebleeds affect about 90% of people with HHT and are the most common symptom of the disease. 
  • Nosebleeds are often the earliest symptom of HHT; typically nosebleeds begin around age 12, but can appear as early as infancy or as late as adulthood.
  • The absence of nosebleeds does not mean a patient does not have HHT. It has recently been reported that some patients will experience their first nosebleed at age 70!
  • Nosebleeds can vary from a mere social nuisance to severe, sometimes causing lots of blood loss and even transfusion dependence. The Epistaxis Severity Score (ESS) is a standardized tool for measuring how severe your nosebleeds are. Sharing your ESS score with your physician is important for determining a proper treatment plan.
  • Iron deficiency and anemia are common among people with HHT and are primarily a consequence of nasal and GI bleeding. This can lead to shortness of breath, exercise intolerance, and fatigue. Iron deficiency tends to be both under-diagnosed and under-treated even though anemia is found in ~50% of all HHT patients.
Hands, Face & Mouth
  • 90-95% of people with HHT have telangiectasia on the skin of the hands, face, and mouth, although they may not be visible until age 30 or 40.
  • Telangiectasia appear as tiny red or purple spots between the size of a pinpoint and pinhead.
  • Rupture and bleeding of telangiectasia on the mouth, face, or hands is less common than of those in the nose.
  • Telangiectasia have a tendency to become more numerous with increased age.
GI Tract
  • 80% of HHT patients have telangiectasia in the stomach or intestines, though it is estimated that only 30% will develop obvious gastrointestinal (GI) bleeding which usually starts when the patient is 50 or 60.
  • HHT-related GI bleeding risk increases with age.
  • Telangiectasia in the GI tract do not cause pain.
  • Symptoms of GI bleeding include black or bloody stool and/or anemia.

Definitions of GI bleeding in HHT patients:

  1. Mild HHT-related GI bleeding: Patient who meets their hemoglobin goals* with oral iron replacement.
  2. Moderate HHT-related GI bleeding: Patient who meets their hemoglobin goals* with IV iron treatment.
  3. Severe HHT-related GI bleeding: Patient who does not meet their hemoglobin goals* despite adequate iron replacement or requires blood transfusions.

*Hemoglobin goals should reflect age, gender, symptoms and co-morbidities (Faughnan et al., 2020).

Arteriovenous Malformations (AVMs)

Arteriovenous malformations (AVMs) are large vascular malformations that can occur in the liver, lungs, brain, and sometimes the spine. AVMs cannot be seen without proper imaging procedures.


At least 40% of people with HHT have lung AVMs (also known as pulmonary AVMs, or PAVMs). A recent study indicated that 60% of children with HHT will develop PAVMs and 30% who had a negative PAVM screening will develop one within 5 years. People with HHT1 (ENG) are 5-10 times more likely to have PAVMs.

Lung AVMs can lead to serious complications, such as stroke, so it is important to be screened.

  • If the artery leading into a lung AVM is larger than 2-3 mm in diameter, small blood clots can travel through the lung AVM and go to the brain causing a stroke.
  • Migraine headaches can be a sign of brain abscess caused by lung AVMs but most PAVMs are easily treatable.
  • Lung AVMs can cause low oxygen saturation which, along with pulmonary hypertension, can lead to shortness of breath, exercise intolerance, and fatigue.
  • PAVMs have a high risk of rupturing when pregnant due to increased blood volume. 

Most PAVMs are easily treatable once identified through screening.


Liver vascular malformations (VMs) are present in 75% of people with HHT, but range in severity with approximately 10% causing symptoms and complications. Liver VMs occur more commonly in women and often present after the age of 50.

Symptoms are typically more severe in patients with HHT2 (ACVRL1). Symptoms may occur with aging, when the heart has been overworked for years by pumping extra blood through the low-resistance pathway of the AVM and by chronic anemia. This can lead to shortness of breath, exercise intolerance, and fatigue. Other complications can include high output heart failure, portal hypertension, encephalopathy, mesenteric ischemia, and biliary ischemia.

Treatments may include use of anti-angiogenic drugs or liver transplant.


At least 10% of HHT patients have brain VMs which can be successfully treated in most cases. The HHT International Guidelines recommend brain VM screening for anyone diagnosed with HHT, regardless of their age, because they can rupture without warning.

VMs can form at least into young adulthood, so repeated screening is necessary. The chance of rupture is 0.3-0.5% per year. Children are more likely to present with hemorrhage than adults.

Seizures and headaches can also result from VMs in the brain.


Spinal AVMs are rare, affecting only about 1% of HHT patients. They can cause back pain or swelling, upper leg pain, and sometimes lead to loss of feeling or mobility in an arm or leg. If untreated, spinal AVMs can lead to further motor or sensory deficit, aneurysm, and high blood pressure.

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