You look in the mirror one morning and barely recognize your reflection — an all-too-familiar experience for many people living with hereditary angioedema (HAE). Your lips and eyelids are drastically swollen, yet there’s no skin discoloration, no itching, and no obvious trigger.

For some people, swelling keeps coming back for no clear reason. One month, it may happen in the belly. Another month, it may affect the hands or throat. Regular allergy tests may not show what’s causing the swelling.

Hereditary angioedema is a rare genetic condition that causes sudden, severe swelling in the deep layers of the body’s tissues. HAE attacks can strike with little to no warning and won’t respond to standard allergy medications.

🗳️ Which HAE symptom affects you most?

Skin or limb swelling

Belly pain or digestive symptoms

Throat, tongue, or voice changes

None of these apply to me.

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This article explains HAE symptoms, warning signs, common triggers, and when to get emergency care.

What Are the Symptoms of Hereditary Angioedema?

HAE causes episodes of deep swelling, called angioedema, in three main areas: the skin and limbs, the digestive tract, and the throat and airways. Not everyone with HAE goes through all three types of attacks. However, 50 percent of people living with HAE will experience all three at some point in their lives.

Skin and Extremity Swelling

The most common type of HAE attack affects the skin. Swelling often appears in the face, eyelids, lips, hands, feet, and genitals. The swelling may make the skin appear pale. On darker skin tones, the swelling may be less visually apparent — though it’s still very much present.

Hives are typically absent. The swelling doesn’t itch. It also doesn’t leave a dent when you press on the skin. Swelling may be more pronounced on one side of the body, and when severe, the area can feel tight, painful, or sore.

Abdominal Symptoms

When swelling affects the intestines, it can cause severe abdominal (belly) pain, nausea, vomiting, and diarrhea. Without treatment, these attacks can quickly lead to dehydration and, in some cases, low blood pressure.

The pain is often so intense that it mimics a surgical emergency like appendicitis. As a result, many people with undiagnosed HAE have undergone unnecessary abdominal surgeries.

Throat and Tongue Swelling

Swelling can also reach the throat, tongue, and upper airway — a condition doctors call laryngeal angioedema, or swelling of the voice box. Symptoms include:

• A change in voice
• Hoarseness
• Difficulty swallowing
• Trouble breathing

About half of people with HAE will experience at least one throat attack in their lifetime.

Without a diagnosis and the right treatment, throat swelling can be life-threatening. Facial swelling can raise the risk of swelling in the throat. If your face starts to swell, watch your symptoms closely.

What Triggers an HAE Attack?

Many HAE attacks happen with no clear cause. When there is a trigger, these are the ones people report most often:

• Stress — Stress is one of the most common HAE triggers. This can include emotional stress, physical stress, or anxiety before a difficult event.
• Illness or infection — Viral infections, such as colds and the flu, can trigger HAE attacks. Even a mild illness may be enough to start an attack.
• Dental procedures — Dental work can injure the mouth, trigger swelling, and raise the risk of throat swelling. Surgery and other medical procedures may carry a similar risk.
• Injury or pressure — Minor physical trauma or sustained pressure on a body site can trigger swelling there. Even repetitive, everyday activities like prolonged typing or using vibrating power tools have been reported as triggers.
• Hormonal changes — Menstruation, pregnancy, and estrogen-based medicines, including oral contraceptives and hormone replacement therapy, can increase attack frequency and severity in some people.
• ACE inhibitors — This class of blood pressure medicine is known to worsen HAE. People with HAE should talk to their doctor before starting any blood pressure treatment.

Triggers vary significantly from person to person. Keeping a diary of attacks, including what happened in the hours before, can help identify personal patterns.

What Are the Early Warning Signs of an HAE Attack?

For many people with hereditary angioedema, an attack doesn’t start with visible swelling. An estimated 65 percent to 70 percent of attacks are preceded by early signals that appear hours before any physical changes.

Knowing what to look for and what happens next can help you respond more effectively.

Physical and Emotional Warning Signals

Many people notice a tingling, tightness, or prickling sensation in the area where swelling is about to develop. Others feel profound fatigue, nausea, or sudden emotional shifts — such as anxiety, irritability, or a general sense of feeling “off” — before any visible changes appear. Learning to read these signals early is valuable in managing HAE.

About 1 in 3 people with HAE may notice a skin change called erythema marginatum before or during an attack. This may be more common in children. Erythema marginatum looks like flat, discolored, maplike marks on the skin.

Erythema marginatum is not the same as hives. It does not itch or feel raised. This can help tell HAE apart from a typical allergic reaction.

How Does an HAE Attack Progress?

Once swelling begins, an HAE attack builds much more slowly than a typical allergic reaction. Unlike an allergy, which can flare within minutes, HAE swelling tends to worsen steadily over the first 24 hours before reaching its peak.

From there, swelling gradually fades over the next two to three days, and a single episode can last anywhere from a few days to a full week.

Taking HAE-specific medication early — during that initial warning window — may result in a shorter, milder attack. Tracking your personal warning cues in a symptom diary can help you recognize that window and take action before swelling fully sets in.

When Should You Seek Emergency Care?

Throat and airway involvement is the most dangerous type of HAE attack and can develop within hours of the first symptoms.

Seek emergency care right away if you or someone with HAE notices:

• Swelling in the throat or tongue
• Hoarseness or a change in voice
• Difficulty swallowing
• Trouble breathing or noisy breathing
• A feeling that the throat is tightening or closing
• Facial swelling, which may signal that throat involvement is developing

Don’t wait to see if symptoms improve. Antihistamines, epinephrine, and corticosteroids aren’t effective for throat swelling from HAE. So emergency rooms must use targeted, HAE-specific acute therapies — such as C1 inhibitor concentrates or bradykinin receptor antagonists (medications that block the chemical signal causing swelling) — to safely stop the swelling.

People with HAE should work with their doctor ahead of time on an emergency action plan, including which HAE-specific medications to use and when to call emergency services.

How Do Repeated HAE Attacks Affect Daily Life?

Without treatment, HAE can be relentlessly disruptive. Untreated attacks can occur roughly every one to two weeks, but they can sometimes happen as often as every three days.

At that frequency, maintaining a steady job, attending school, and keeping personal commitments can become incredibly difficult. HAE can also affect a person’s emotional well-being. It can be hard to live with the worry of not knowing when the next attack may happen.

Another challenge is that HAE can look like other common conditions. Because of this, some people have attacks for years before they get the right diagnosis.

Getting that diagnosis changes the picture. With the right treatment plan, many people with HAE are able to significantly reduce how often attacks occur — and get back to living life on their own terms.

Taking the Next Step

HAE symptoms can look different from person to person. Some people have mild skin swelling. Others have severe belly pain or throat swelling, which can be life-threatening.

Knowing that these symptoms may be part of one genetic condition — not separate allergic reactions — can be an important step toward getting the right care.

Start tracking your symptoms today. Write down when attacks happen, how long they last, and what happened right before. Include early warning signs, such as feeling very tired or tingling.

If you have ever had throat swelling, tell your doctor. They can help you make an emergency action plan. An allergist or immunologist with HAE experience can confirm your diagnosis, help you find your triggers, and create a treatment plan that fits your life.

Join the Conversation

On myHAEteam, people share their experiences with hereditary angioedema, get advice, and find support from others who understand.

What early warning sign do you notice first before an attack? Let others know in the comments below.