Hereditary angioedema diagnosis and management
Specialist diagnosis and long-term care of hereditary angioedema — an inherited condition causing recurrent deep swelling that does not respond to adrenaline, antihistamines or steroids and needs its own specific treatment and emergency plan.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- HAE is a rare inherited condition causing recurrent deep swelling; it is driven by bradykinin, not histamine.
- It does NOT respond to adrenaline, antihistamines or steroids — it needs its own specific medicines, so every patient must have a clear emergency plan.
- Diagnosis uses specific blood tests (complement C4 and C1-inhibitor level and function) alongside the history and family history, and is often delayed because attacks mimic allergy or other emergencies.
- Throat (laryngeal) swelling can be fatal and is a 999 emergency; tummy attacks can cause severe pain and be mistaken for other conditions.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
A clear diagnosis that explains years of unexplained swelling or tummy pain
Treating HAE attacks with adrenaline, antihistamines or steroids alone is the wrong approach, because bradykinin-driven swelling does not respond to them.
Specific blood tests (such as C4 and C1-inhibitor level and function) confirm the diagnosis within weeks. You are given an on-demand treatment and a...
A written, individualised emergency plan, especially for throat attacks, shared with those around you.
Specific blood tests (such as C4 and C1-inhibitor level and function) confirm the diagnosis within weeks. You are...
You learn to recognise attacks early and to use your specific on-demand treatment promptly. Triggers such as ACE...
If attacks are frequent or severe, preventive treatment is started and adjusted. The frequency and severity of...
Short-term preventive cover is arranged before triggers such as dental work or surgery, and care is planned...
What is hereditary angioedema (HAE) diagnosis and management?
Hereditary angioedema (HAE) is a rare, inherited condition that causes attacks of deep swelling (angioedema), often of the hands, feet, face, tummy, genitals or throat. It is rare — estimated at around 1 in 50,000 people — but important, because attacks can be severe and swelling of the throat can be life-threatening.
HAE is different from ordinary allergic swelling. Most types are caused by a problem with a blood protein called C1 inhibitor, which leads to a build-up of a chemical called bradykinin. Because the swelling is driven by bradykinin and not histamine, it does not respond to adrenaline (epinephrine), antihistamines or steroids — the medicines used for allergic reactions. This is the single most important thing to understand about HAE, because using the wrong treatment in an emergency wastes critical time.
Diagnosis is made by a specialist, usually a clinical immunologist, using the history, family history and specific blood tests — typically complement C4 and the level and function of C1 inhibitor. Tummy attacks can mimic other emergencies, and throat attacks can be mistaken for allergy, so the diagnosis is often missed or delayed.
Management is lifelong and has three parts: treating attacks quickly with specific medicines (on-demand treatment), preventing attacks where they are frequent or severe (long-term prophylaxis), and protecting against attacks around triggers such as dental work or surgery (short-term prophylaxis). With the right plan and a clear emergency plan, most people lead full lives.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Why HAE is not treated like an allergy
| Allergic (histamine) swelling | HAE (bradykinin) swelling | |
|---|---|---|
| Often itchy or with hives | Yes | Usually not |
| Responds to antihistamines | Yes | No |
| Responds to adrenaline/steroids | Yes (for allergy) | No |
| Main treatment | Adrenaline, antihistamines, steroids | C1-inhibitor or icatibant; specific prevention |
Treating an HAE attack as an allergy wastes time. Every person with HAE should carry an emergency plan that names the right specific treatment.
Preparing for your treatment
- Make a record of your swelling attacks: where on the body, how often, how long, what seems to trigger them, and whether they itch.
- Note any episodes of unexplained, severe tummy pain, which can be HAE attacks of the gut.
- Bring a detailed family history, as HAE is inherited and often affects relatives across generations.
- List all your medicines, including any blood-pressure tablets (ACE inhibitors) and hormone treatments, which can affect swelling.
- Note whether antihistamines, steroids or adrenaline have ever helped your swelling — in HAE they usually do not.
- Take photos of swelling when it happens, as it often settles before the appointment.
- Be ready to discuss any upcoming dental work, surgery or pregnancy plans, which need specific precautions.
What happens
The specialist takes a detailed history of your swelling attacks, your family history, and your medicines, and examines you. They are looking for the pattern of bradykinin-driven swelling: recurrent attacks without hives, episodes of severe tummy pain, throat involvement, and a family history.
To confirm the diagnosis, specific blood tests are arranged — usually complement C4, and the level and function (activity) of C1 inhibitor. Both the level and the function matter, because in one form of HAE the level looks normal but the protein does not work. Sometimes tests are repeated, or genetic testing is used, particularly for the form with normal C1 inhibitor.
Once HAE is confirmed, the specialist puts together a lifelong management plan: a specific on-demand treatment to use in an attack, a written emergency plan (especially for throat attacks), consideration of preventive medicines if attacks are frequent or severe, and a plan for cover around triggers such as dental or surgical procedures. Care is usually based at a specialist centre, and relatives are offered testing.
Is this treatment right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- Treating HAE attacks with adrenaline, antihistamines or steroids alone is the wrong approach, because bradykinin-driven swelling does not respond to them.
- Standard allergy testing is the wrong test for diagnosing HAE; specific complement and C1-inhibitor tests are needed.
- Relying only on the C1-inhibitor level can miss the form where the level is normal but the protein does not work — function must be checked too.
- A throat attack is a medical emergency, not something to manage at a routine appointment.
Delay or rearrange if…
- You are having an airway-threatening attack now — use your on-demand treatment if you have it and call 999.
- Specific blood tests need to be timed or repeated for a reliable result.
- You are pregnant or planning pregnancy, as this changes which medicines are suitable and needs specialist planning.
- A clear diagnosis and emergency plan are not yet in place before any non-urgent procedure.
Alternatives to discuss
- For the choice of on-demand treatment: C1-inhibitor concentrate (into a vein) or icatibant (under the skin), depending on what suits you.
- For prevention: lanadelumab, berotralstat or regular C1-inhibitor, with older options such as tranexamic acid or attenuated androgens in selected cases.
- Short-term preventive cover around procedures instead of long-term prophylaxis where attacks are otherwise infrequent.
- Watchful management with on-demand treatment alone where attacks are rare and mild.
- A second opinion at a specialist HAE centre for difficult or uncertain cases.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- A clear diagnosis that explains years of unexplained swelling or tummy pain
- The right specific treatment for attacks, instead of medicines that do not work
- A written emergency plan for throat swelling, which can be life-saving
- Preventive treatment that can greatly reduce the number and severity of attacks
- Protection around triggers such as dental work, surgery and pregnancy
- Testing and advice for blood relatives, who may also be affected
Risks & complications
- Delay or difficulty in diagnosis, as attacks can mimic allergy or other emergencies
- Needing specific blood tests that sometimes have to be repeated
- Living with the unpredictability of attacks while a plan is established
- Side effects from preventive medicines, which vary by drug and are monitored
- Attacks of the gut being mistaken for other conditions and over-investigated
- Reactions or injection-site effects from specific treatments
- Needing to change preventive treatment if attacks are not controlled or side effects occur
- A throat (laryngeal) attack that threatens the airway — a medical emergency
- Serious harm from an attack that is wrongly treated as an allergy and so delayed
- A diagnosis that has implications for several blood relatives
The two greatest dangers in HAE are a throat attack that blocks the airway, and an attack being wrongly treated as an allergy so the right medicine is delayed. Because HAE does not respond to adrenaline, antihistamines or steroids, every person with HAE needs a clear written emergency plan, ready access to a specific on-demand treatment, and a way to tell emergency staff what they have. Discuss your personal attack pattern, your triggers (including ACE inhibitors and some hormone treatments), and what to do for a throat attack.
Published figures to discuss
HAE is rare and attack patterns vary widely between people, so single figures rarely apply to an individual. The most important numbers concern how serious untreated throat attacks can be and how access to preventive medicines is decided. The figures below are broad and for context only.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| How common HAE is | Rare — estimated around 1 in 50,000 people | Because it is rare and mimics other conditions, diagnosis is often delayed by years. | Hereditary angioedema: a rare but serious and commonly misdiagnosed disease — PMCncbi.nlm.nih.govPublished figure |
| Danger of untreated throat (laryngeal) attacks | Can be fatal by suffocation if not treated | Death is far more likely in people whose HAE is undiagnosed or wrongly treated, which is why a correct diagnosis and emergency plan are vital. | Hereditary angioedema: a rare but serious and commonly misdiagnosed disease — PMCncbi.nlm.nih.govSource-linked context |
| Access threshold for some preventive medicines (England) | Often based on attack frequency (for example around two or more significant attacks a month for certain drugs) | National rules guide who can have which preventive treatment; your specialist will explain your eligibility. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is no physical recovery from diagnosis; 'afterwards' is about living well with a lifelong condition. The aim of management is to treat attacks quickly, reduce how often they happen, and make sure you and those around you know exactly what to do in an emergency.
- Learning to recognise the early signs of an attack
- Carrying and knowing how to use a specific on-demand treatment
- Some attacks still happening, even on preventive treatment, though usually fewer and milder
- Regular specialist review and occasional changes to the plan
- Telling dentists, surgeons and emergency staff that you have HAE
Aftercare
- Carry your specific on-demand treatment and your written emergency plan at all times.
- Treat attacks early with the specific medicine you have been given — not adrenaline, antihistamines or steroids.
- Treat any throat swelling or breathing difficulty as a 999 emergency, even after using your treatment.
- Tell dentists and surgeons you have HAE well before any procedure, so preventive cover can be arranged.
- Avoid known triggers where possible, including ACE inhibitor blood-pressure tablets and some hormone treatments, under medical advice.
- Keep a diary of attacks to help judge whether preventive treatment is working.
- Make sure family and close contacts know you have HAE and what to do in an emergency, and arrange testing for relatives.
- Diagnosis confirmed and type of HAE understood
- Specific on-demand treatment supplied and training given
- Written emergency plan for throat attacks to hand
- Triggers reviewed (ACE inhibitors, hormone treatments)
- Plan for cover before dental or surgical procedures agreed
- Attack diary started
- Specialist-centre follow-up and family testing arranged
⚠ Get urgent help if…
- Swelling of the tongue, throat or voice box, or any difficulty breathing, swallowing or change in voice — call 999
- An attack not settling after your specific on-demand treatment — seek emergency care; a throat attack can still be dangerous
- Severe, unexplained tummy pain, which can be an HAE attack of the gut
- Feeling faint or collapsing during an attack
- Rapidly spreading swelling, especially towards the face or neck
- Any swelling treated as an allergy that is not improving — make sure staff know you have HAE
- Running low on your on-demand treatment, so you cannot treat an attack
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good outcome is a confirmed, correctly typed diagnosis; ready access to a specific on-demand treatment; a clear emergency plan; and, where needed, preventive treatment that reduces how often and how severely attacks happen. For many people, the most valuable result is confidence that a throat attack can be treated and that they are no longer being given medicines that do not work.
Management cannot cure HAE or stop every attack, and preventive medicines reduce but do not always abolish attacks. The plan is tailored to your attack pattern and reviewed over time. Success is measured by fewer and milder attacks, fewer emergencies, and a life less limited by the condition — not by blood levels alone.
HAE is a lifelong condition, so management continues for life and is reviewed regularly at a specialist centre. Attack patterns can change over time — for example with age, hormones or pregnancy — so treatment, including preventive medicines and the on-demand plan, is adjusted accordingly. Even when attacks are well controlled, the emergency plan and on-demand treatment remain essential, because attacks can still occur.
Related tests, treatments or support
HAE management is coordinated with other specialists as needed — for example anaesthetists and surgeons for cover before procedures, obstetricians during pregnancy, and dentists before dental work. Because some blood-pressure tablets (ACE inhibitors) and oestrogen-containing treatments can worsen attacks, management is combined with a review of these medicines. Confirmed HAE also leads to testing and advice for blood relatives.
Follow-up & long-term care
Follow-up is lifelong, usually at a specialist immunology centre, to review your attack pattern, treatment, emergency plan and on-demand supply, and to support family testing. Ask who to contact about attacks, running low on treatment, or planning a procedure or pregnancy, and make sure your emergency plan is always up to date.
- Keep an in-date specific on-demand treatment available at all times
- Keep your written emergency plan current and shared with those around you
- Continue any preventive treatment as planned, with monitoring where required
- Arrange short-term preventive cover before dental work, surgery or other triggers
- Avoid ACE inhibitors and review hormone treatments under medical advice
- Attend specialist follow-up and keep relatives' testing up to date
Repeat, follow-on and what comes next
- The diagnosis may need confirming with repeat or genetic tests, especially for HAE with normal C1 inhibitor.
- Preventive treatment is changed if attacks are not controlled or side effects occur.
- The plan is adjusted as attack patterns change with age, hormones or pregnancy.
- On-demand treatment and the emergency plan are kept under regular review.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A written, individualised emergency plan, especially for throat attacks, shared with those around you.
- Ready access to an in-date specific on-demand treatment and training in how to use it.
- A named specialist contact and clear routes for attacks, running low on treatment, and planning procedures or pregnancy.
- Regular specialist-centre review of attack frequency, treatment and eligibility for preventive medicines.
- Testing and advice for blood relatives, and review of triggers such as ACE inhibitors and oestrogen-containing treatments.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Length and complexity of the specialist consultations
- Specific blood tests, including complement C4 and C1-inhibitor level and function, and any genetic testing
- On-demand treatments such as C1-inhibitor concentrate or icatibant
- Preventive medicines and the monitoring they require
- Short-term preventive cover before dental work, surgery or other triggers
- Long-term specialist follow-up and family testing
- The specialist's consultation fee
- Which blood and genetic tests are included and their cost
- The cost and supply arrangements for on-demand treatment
- The cost of any preventive medicines and their monitoring
- Cover and cost for treatment around procedures or pregnancy
- Long-term follow-up and family testing arrangements
- What happens, and what it costs, if the diagnosis is uncertain, and the cancellation policy
On the NHS? Hereditary angioedema is diagnosed and managed on the NHS, usually at a specialist centre, with some specific preventive medicines subject to national access rules based on attack frequency and severity.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not being warned clearly that adrenaline, antihistamines and steroids do not treat HAE attacks.
- No written emergency plan, or no ready access to a specific on-demand treatment.
- Checking only the C1-inhibitor level and not its function, missing one type of HAE.
- No plan for cover before dental work or surgery, which can trigger dangerous attacks.
- Not advising relatives to be tested, or not reviewing medicines such as ACE inhibitors and oestrogens.
Marketing red flags
- Treating recurrent swelling as a simple allergy without testing for HAE.
- Offering broad 'allergy panels' or 'intolerance' tests as the answer to bradykinin-driven swelling.
- Not providing a specific on-demand treatment or a written emergency plan.
- Promising a quick cure for a lifelong condition.
- Downplaying the danger of throat attacks or the need for specialist-centre care.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Which type of HAE do I have, and were both the level and function of C1 inhibitor checked?
- What is my specific on-demand treatment, and how and when do I use it?
- What exactly should I do for a throat attack, and what is in my written emergency plan?
- Do I need preventive treatment, and am I eligible under the national rules?
- How should procedures, dental work or pregnancy be managed?
- Should my relatives be tested, and how is that arranged?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my treatment, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this treatment not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Why don't adrenaline, antihistamines or steroids work for my swelling?
How is HAE diagnosed?
What should I do if my throat swells?
Can attacks be prevented?
Will my children or relatives have it?
Can I get treatment on the NHS?
Do I need to tell my dentist or surgeon?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: HAE UK — hereditary angioedema patient support NICE TA606 — Lanadelumab for preventing recurrent attacks of HAE NICE TA738 — Berotralstat for preventing recurrent attacks of HAE Hereditary angioedema: a rare but serious and commonly misdiagnosed disease — PMC Hereditary angioedema due to C1-inhibitor deficiency: current therapeutic approaches — PMC Hereditary Angioedema — StatPearls (NCBI Bookshelf) NHS — Swelling under the skin (angioedema)
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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