Hereditary Hemorrhagic Telangiectasia (HHT)

Hereditary hemorrhagic telangiectasia (HHT) is an inherited condition that prevents blood vessels from developing properly. When someone has HHT, their blood vessels are fragile and bleed easily. In children, this can cause frequent nosebleeds. In adults, the condition can be more serious.

HHT is relatively rare. Researchers estimate that between one and two people out of every 10,000 have the condition, which is also known as Osler-Weber-Rendu disease (OWRD). It affects adults and children of all racial groups.

There is no cure for HHT but with proper treatment, people with HHT can live full lives.

The most common sign of HHT in children is frequent nosebleeds. This often starts around age 12, though some children with HHT start having nosebleeds as infants. Other people with HHT do not have recurring nosebleeds until they reach adulthood. A small number of people with HHT never experience nosebleeds at all.

Other symptoms of HHT include:

• Iron-deficiency anemia, leading to fatigue, shortness of breath, and dizziness
• Purple or red spots on the skin of the hands, fingertips, face, nose, lips, and inside of the mouth
• Migraine headaches
• Blood in the stool, which may appear as drops of fresh blood or dark stool

How HHT affects adults

Some problems associated with HHT can become life threatening, however, the condition is usually manageable if diagnosed and managed effectively.

Adults with HHT are at increased risk of the following conditions:

• Heart failure
• Pulmonary hypertension (high blood pressure in the lungs)
• Stroke
• Seizures
• Loss of feeling or mobility in an arm or leg

HHT is a genetic condition, meaning that is passed down to a child by a parent. If a father or mother has HHT, their children have a 50 percent chance of being born with the condition.

People with HHT can develop abnormal blood vessels in several areas of the body.

• If they are on the skin, abnormal blood vessels are called telangiectasias. They often show up as red or purple spots on the lips, tongue, fingers, or ears.
• Larger abnormal blood vessels, ranging in size from millimeters to centimeters, can develop in the heart, lungs, GI tract, brain, or liver. These vessels are called arteriovenous malformations (AVMs).

Hereditary hemorrhagic telangiectasia (HHT) can be hard to diagnose, particularly in children, because its symptoms often develop in adolescence or adulthood and resemble those of several other conditions.

Diagnosis typically begins with a medical exam. The diagnosing clinician will want to know if a child has nosebleeds and if so, how often. They may also examine the child’s skin for telangiectasia.

A detailed family history will help determine if a parent or sibling has HHT, in which case, the child has a 50 percent chance of also having the condition. In some cases, the doctor may recommend genetic testing to detect whether the child has a gene mutation associated with HHT.

In general, HHT does not affect major organs until a child reaches adulthood. However, if a doctor suspects that an internal organ has been affected, they may order one or more of the following tests:

• Echocardiogram to look for signs of HHT in the heart
• Computed tomography (CT scan) to look for signs of HHT in the lungs or liver
• Ultrasound to look for signs of HHT in the lungs or liver
• Magnetic resonance imaging (MRI) scan to look for signs of HHT in the brain
• Endoscopy to look for signs of HHT in the intestines

If a child has HHT, the first step of medical care is to control nosebleeds and iron deficiency that can result from losing a large amount of blood.

Treatment may include:

• Electrocautery, a procedure that applies electricity to nasal tissues to stop them from bleeding
• Iron supplementation to reverse anemia

The Vascular Anomalies Center (VAC) at Boston Children's Hospital provides a wide range of comprehensive services for people of all ages with HHT and other vascular malformations, and their physicians. In addition to direct patient care at Boston Children's, our interdisciplinary clinicians make their expertise available to patients and physicians throughout the United States and internationally through consultations and reviews.

Once a treatment plan is established, VAC staff will help coordinate appointments at Boston Children’s with specialty clinics as needed. If you are from outside the area, they will help to develop treatment options closer to home, when possible.