Does your child suddenly have swelling? Let's talk about Hereditary Angioedema (HAE)!

Have you ever noticed your little one suddenly swelling up in different parts of their body, sometimes their face, hands, and feet? Or is your child showing signs of trouble breathing along with stomach aches? Perhaps there is a very rare but important condition behind these symptoms. Today we are going to talk about one such condition, namely `Hereditary Angioedema (HAE). Don't worry, we will talk about this in a simple way that you can understand.

What is this `Hereditary Angioedema (HAE)`?

Simply put, `Hereditary Angioedema` (also known as `HAE` for short) is a very rare, genetic (meaning it can be passed down through generations) condition. It causes swelling in various parts of your child's body. This swelling can occur in areas that are visible to the outside, such as the arms, legs, and face, or sometimes in areas that are not visible to us, such as the tissues of the child's airways (breathing system) or digestive system (guts) .

Now you may be wondering why this swelling occurs. This swelling occurs because the tiny blood vessels in the child's body, called ``Capillaries,'' leak fluid out of them and collect in the surrounding tissues. When this fluid collects, it can block the flow of blood or lymph through them. It is difficult to predict when this swelling and its associated symptoms (also called ``HAE attacks'') will occur. Also, sometimes this can stop with a small swelling, but sometimes it can be severe enough to be life-threatening.

In medicine, the word "angio" (`Angio-`) refers to blood vessels. "Edema` (`-edema`) refers to swelling caused by fluid accumulation in tissues. There are many types of `angioedema`, each with different causes. `HAE` is the rarest of these. It is called `congenital`, meaning that a person is born with the condition.

If your child is diagnosed with HAE, you may feel very uncertain about what to expect. But knowing this can help you put your mind at ease: Research is ongoing into new treatments for people of all ages with HAE, including children. Your doctor can help you understand which treatments are right for your child and what to expect in the future.

Are there types of `HAE`?

Yes, although `HAE` is a type of `angioedema`, doctors divide `HAE` into several other types:

• Type I HAE: This is the most common type . About 85% of all HAE patients have this type. This is caused by the child's body not producing enough of a special protein called C1-inhibitor (also known as C1-INH). When this C1-INH protein is low, inflammation and swelling can occur in the body. This is also called C1-INH deficiency.
• Type II HAE: This is the second most common type. In this, the child's body produces the protein C1-INH, but it does not function properly.
• HAE with normal C1-INH: This is the least common type . The child's C1-INH protein levels and activity are normal, but other causes cause swelling.

The first two types (Type I and Type II HAE) combined, affect about 1 in 50,000 people . That means that in a country like the United States, about 6,000 people suffer from this type of HAE. Researchers don't know exactly how many people with HAE have normal C1-INH levels, but they say it's very rare.

What are the symptoms of HAE?

The symptoms of HAE can vary from person to person. Some common symptoms include:

• Swellings that appear on various parts of the child's body, for example , the arms, legs, eyelids, lips, and genital areas .
• Symptoms of inflammation in the child's digestive system (Gastrointestinal (GI) tract). This can include nausea, vomiting, stomach cramps, and diarrhea .
• Symptoms caused by swelling in the child's mouth, throat, and airways . These may include difficulty swallowing, a swollen tongue, a raspy sound when breathing in, and a change in voice .

Most importantly: If your child is having trouble breathing or swallowing, call the nearest emergency room or take your child to the hospital immediately. Swelling of the airways is a very serious, life-threatening complication of HAE. It can be fatal if not treated quickly.

HAE does not cause hives. This is the main difference between HAE and other types of angioedema, such as acute allergic angioedema. However, some people with HAE may develop a non-itchy red rash before the swelling occurs, which can be a sign of an upcoming attack.

An `HAE attack` usually lasts about three to five days . These `attacks` come and go suddenly, so it's hard to say exactly when and how they will happen.

When do HAE symptoms start?

HAE symptoms usually begin in childhood or adolescence . They can become more severe during puberty. Some children may start to experience symptoms as young as 2 years old . About 50% of people with HAE type I or II develop symptoms by the age of 10. After puberty, these attacks may become more frequent and severe. Almost everyone with HAE type I or II develops symptoms by the age of 20.

People with HAE who have normal C1-INH levels tend to have a somewhat later onset of symptoms – usually in their late teens or early adulthood.

What are the triggers for an HAE attack?

It is not always clear what the exact ``trigger`` is that causes an HAE attack. However, some of the ``triggers`` that have been identified are:

• Physical injury or minor accident: Imagine your child falls while playing one day.
• Dental treatments: Things like extracting a tooth or filling it.
• Surgery: An operation , whether minor or major.
• Stress or emotional pressure: A school exam or even a small fight with a friend can have an impact.
• Viral infections: Things like the flu and cold.
• Some physical activities: For example, things like typing continuously, hitting with a hammer, or digging with a hoe.

You may not immediately understand what triggers your child to have an attack. However, it can be very helpful to keep a journal of the time the attack occurred and what the child was doing at the time (for example, whether the child was sick or stressed) .

What is the real cause of HAE?

Both HAE types I and II are caused by a mutation (or change) in a gene called SERPING1. This gene tells your child's body how to make a protein called C1-INH. If your child has HAE type I, this gene mutation means their body can't make enough C1-INH. If your child has HAE type II, their body can make C1-INH, but the gene mutation means the protein doesn't work properly.

Researchers are still investigating the causes of HAE with normal C1-INH levels, but they do know that mutations in the following genes may be responsible:

• `F12`
• `ANGPT1`
• `PLG`
• `KNG1`

In some cases, HAE can be present without any identified genetic mutation. Doctors call this "HAE-unknown."

The genetic mutations that cause HAE cause certain proteins in the child's body to not work properly. These proteins help fluids flow normally through the child's small blood vessels (capillaries). So, when these proteins don't work properly, fluids leak out and accumulate in the tissues around the child's blood vessels. That's what causes the symptoms of HAE.

Does HAE come from the family?

Yes, HAE is inherited in an autosomal dominant pattern. Simply put, it requires only one abnormal gene to cause the condition. A child can inherit this abnormal gene from either their mother or father.

Many people with HAE have a family history of the disease. However, sometimes a person can develop a gene mutation randomly (a "de novo" or "new" mutation) without any family history.

How do doctors find this?

If your child shows symptoms of HAE, a doctor will do the following:

• Does a physical examination .
• You will be asked about your child's symptoms and medical history.
• Blood tests are done to check the child's `C1-INH` level and activity .
• In some cases, genetic testing is done to see if there are genetic mutations that cause HAE.

What are the treatments for HAE?

There are two main types of medications for people with HAE:

• On-demand medications: These are medications that are given as soon as an HAE attack occurs. For example, medications like Berinert® or Kalbitor®. Taking these medications as soon as possible after symptoms start can reduce the severity of the attack and prevent life-threatening complications.
• Prophylactic medications: These are medications that reduce the risk of having an attack. Examples include Cinryze®, Haegarda®, or Takhzyro®. A doctor may prescribe these medications to be used during a known trigger (such as a trip to the dentist), or for long-term use, depending on your child's needs.

According to medical experts, on-demand medications are essential and life-saving. Even if your child is taking prophylactic medications, these on-demand medications should be available at all times, everywhere (at home and at school).

The doctor will tell you exactly what medications your child needs, how to give them, and when. He will also explain what medications can be given to your child based on their age. Be sure to follow the instructions exactly, and be sure to ask questions if there is anything you are unsure about.

How quickly will I recover after treatment?

With on-demand medication, your child will start to feel better relatively quickly during an HAE attack. His symptoms should improve within 30 minutes to two hours of starting treatment. Your doctor will give you more information about how to manage the treatment at home and what to expect.

How to care for a child with HAE?

You may feel helpless when you see your child suffering from an HAE attack. However, there are many things you can do for your child before, during, and after an attack:

• Always keep on-demand medications handy: These can be life-saving. You should be able to recognize when your child needs these medications. You should also know how to give them. Your doctor will tell you more about this.
• Don't treat an HAE attack as an allergy: Medications such as antihistamines and epinephrine, which are commonly given for allergies, will not help an HAE attack. Therefore, do not give these medications to your child.
• Be aware of the triggers that can trigger an attack: Triggers vary from person to person. Make a list of things that can trigger an attack in your child and share it with your doctor. Try to keep your child away from those triggers as much as possible. If you can't avoid them, ask your doctor about prophylactic medications.

When do you need to see a doctor?

See a doctor in these cases:

• If you think your child has symptoms of `Hereditary Angioedema`.
• If new symptoms associated with an HAE attack appear, or if existing symptoms change.
• If your child's medicine doesn't seem to be working as expected.

When do you need to go to the emergency room?

If your child experiences any of the following , go to the emergency room immediately:

• If it is difficult to swallow.
• If you have difficulty breathing.
• If you see any signs of swelling of the tongue or throat (even if you were given medication at the first signs of an attack).

These could be signs of a dangerous swelling that affects your child's airway. Don't delay seeking treatment. This swelling can be life-threatening.

What questions should you ask the doctor?

You can ask the doctor questions like these:

• What type of HAE does my child have?
• What treatment do you recommend?
• How do I know when my child needs on-demand medication?
• Does my child need preventive medication? If so, when?
• Are there any activities or situations my child should avoid?
• What can you say about my child's future (outlook)?

How can we have hope for a child with HAE?

HAE is a lifelong condition. However, treatment can reduce the impact of the condition on a child's life. It can also reduce the risk of life-threatening symptoms, such as swelling of the child's airways.

Can HAE be prevented?

There is currently no known way to prevent HAE. If you or your partner has HAE and you are trying to have a baby,It is a good idea to talk to a genetic counselor so that you can understand the chances of your child inheriting this condition.

An important message for you.

When you find out that your child has a genetic condition like HAE, you may feel a variety of emotions: fear, anxiety, confusion, and frustration. You may even blame yourself. But the most important thing you need to know is that this diagnosis is not your fault.

Genetic mutations happen all the time, often for no apparent reason. You can't control the genes your child inherits. But you can play an active role in your child's care – sometimes it's just reassuring them that "you'll be fine."

It can also be helpful to join patient support groups. Talking to parents of children with HAE, as well as adults with the condition, can give you advice and a listening ear. It can also remind you that while HAE is rare, your family is not alone.

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