Episodes of angio-oedema cause swelling of deeper skin tissues, most commonly of the eyelids, lips, genitals, hands, and feet. Sometimes the tongue and throat are affected which may affect breathing. There are various causes. Some people have recurring episodes. Each episode usually clears within a few days. Antihistamines and steroid tablets ease symptoms. If your breathing is affected then go straight to your local accident and emergency department or call for an ambulance urgently.
What is angio-oedema?
Angio-oedema is a condition that can cause swelling of:
- The deeper layers of the skin - these are called the dermis and subcutaneous tissues.
- The tissues just under the lining of the airways, mouth and gut - these are called the submucosal tissues.
The swelling you see when somebody has angio-oedema occurs when cells under the skin surface called mast cells are triggered to release a chemical called histamine. Histamine causes the tiny blood vessels in these tissues to become leaky. Fluid then leaks into the tissues, which makes them swell. The swelling can occur under any part of the skin or submucosal tissues. However, it commonly affects the eyelids, lips, genitals, hands and feet.
Sometimes the tongue, throat and airway are affected and become swollen. The swelling sometimes becomes bad enough to cause difficulty with breathing.
What causes angio-oedema?
In most cases there is no known cause and it is not clear why it occurs. This is called idiopathic angio-oedema. Although the cause is not clear, in up to half of cases there is a link to an autoimmune disorder - for example, chronic urticaria, systemic lupus erythematosus (SLE), or thyroiditis (hypothyroidism). About half of people who have chronic urticaria also have regular episodes of angio-oedema.
In some cases there are known triggers that can cause the release of histamine, which leads to tissue swelling of angio-oedema. The triggers may be as follows:
Some people develop angio-oedema as part of an allergic reaction. Something triggers the immune system, which triggers mast cells to release histamine. For example:
- Allergy to foods - for example, nuts, shellfish, milk, eggs.
- Allergy to drugs - for example, penicillin, aspirin.
- Allergy to latex, insect bites or stings.
The symptoms that may develop with an allergic reaction can vary. For example:
- Some people develop an urticarial rash.
- Some people develop angio-oedema.
- Some people develop an urticarial rash and angio-oedema.
- Some people develop a very severe reaction called anaphylaxis. This usually includes an urticarial rash, angio-oedema, and other symptoms, such as low blood pressure, severe breathing problems, and collapse. Anaphylaxis is rare, but is the most serious type of allergic reaction and can be fatal unless promptly treated.
- Various other symptoms can develop to localised allergies. For example, nasal symptoms if you are allergic to pollen (hay fever), etc.
Non-allergic reaction to a medicine
Some medicines can cause angio-oedema as a side-effect. Medicines for high blood pressure or heart problems, particularly angiotensin-converting enzyme (ACE) inhibitors and angiotensin-II receptor antagonists (AIIRAs) are known to do this.
Some people inherit a tendency to develop episodes of angio-oedema. This is due to a lack of an enzyme called C1 esterase. This condition is called hereditary C1 esterase deficiency. About 1 person in 50,000 inherits the gene for C1 esterase deficiency. Children born to people with this condition have a 50:50 chance of inheriting the condition. Although it is hereditary and most cases first develop in childhood, in some cases the angio-oedema first develops in early adulthood.
How common is angio-oedema?
The number of people affected by angio-oedema is not known, but it is thought that fewer than 1 in 10 people have some episode in their lifetime. Women are affected more often than men. It can occur at any age. However, it most commonly affects people aged 40-60 years (apart from hereditary angio-oedema, which often develops in children). Hereditary angio-oedema is rare and accounts for about 1 in 200 cases of angio-oedema.
What are the symptoms of angio-oedema?
Symptoms of each episode develop quickly, over minutes or hours.
- A typical episode is as follows:
- Areas of the skin become more and more swollen. Most commonly this affects the eyelids, lips, genitalia, hands and feet.
- The surface of the skin may appear normal - it is the tissues just beneath the skin that swell.
- The swellings are often more painful than itchy.
- An itchy urticarial rash often develops at the same time on various parts of the body. (See separate leaflets called Acute Urticaria and Chronic Urticaria for more details.)
- The swelling takes up to 72 hours to ease and to go.
- In some cases, in addition to the above:
- You may become short of breath, wheezy and have difficulty breathing due to swelling of the lining of throat, main airway, tongue and mouth.
- You may develop tummy (abdominal) pain with being sick (vomiting) or diarrhoea.
- Occasionally, angio-oedema is part of a more severe anaphylactic episode (described above).
- Hereditary angio-oedema:
- Typically, this causes recurring episodes. In most cases there are one or more episodes per month. These can occur for no apparent reason, but episodes may be triggered by stress, trauma, minor operations and dental surgery.
- Swellings commonly affect the hands or feet and are painless.
- Up to 1 case in 4 has involvement of the throat, tongue or airway, with some degree of wheezing or breathing difficulty.
- Abdominal pain is common.
- Episodes last for 1-4 days.
What is the treatment for angio-oedema?
Treating each episode
The most important thing is to determine whether an episode of angio-oedema affects breathing, or if it is part of an anaphylactic episode.
- If breathing is affected or if you have any symptoms of anaphylaxis:
- You should go straight to your local casualty (accident and emergency department) or call for an ambulance urgently.
- You may be given adrenaline (epinephrine) by injection, a course of antihistamines, and a short course of steroids. These help to prevent symptoms from getting worse, and help to clear the symptoms more quickly than they would do naturally.
- You will be observed until the symptoms subside.
- Help with breathing, and intensive care, may be needed in severe cases.
- If breathing is not affected and you feel otherwise OK:
- You may be advised to take a short course of antihistamines and steroid tablets. These help to prevent symptoms from getting worse, and help to clear the symptoms more quickly than they would do naturally.
- Most episodes of angio-oedema will clear away within a few days.
- A cool shower or a cold compress on the affected area may ease symptoms.
- If your skin is itchy it is best to try not to scratch, as it may damage the skin. If necessary, rubbing itchy skin with the palms of your hands is better than scratching. Choose clothing that does not irritate the skin. Consider whether any skin creams, soaps, or detergents are making symptoms worse.
- If symptoms get worse and breathing does become affected, then go straight to your local casualty (accident and emergency department) or call for an ambulance urgently.
Follow-up and general advice
Most people who have an episode of simple angio-oedema can be safely managed by their GP. More complex cases can be referred to a specialist. Ideally this will be an immunologist, but is more often a dermatologist as few areas have an immunologist. This is to confirm the diagnosis and, where possible, to identify a cause. The severity of one episode compared with another is unpredictable. So, if you do have an allergy to something, it is best to be aware of what the allergy is.
It is advisable to carry a wallet-sized management card that briefly explains your diagnosis, the best treatment for your acute attacks, and provides contact information for the specialist looking after you.
The specialist will also advise on such things as:
- Whether it is likely to happen again.
- What to do if it does happen again.
- Whether you should carry an injection of adrenaline (epinephrine) with you at all times in case you have a severe episode.
- Advice on avoiding the cause, if you are diagnosed as having an allergy.
Some causes of angio-oedema do not get better easily with antihistamines, corticosteroids or adrenaline (epinephrine). This is commonly the case with hereditary, ACE inhibitor and autoimmune angio-oedema. The specialist will be able to prescribe alternative treatments and advise on what to do if minor surgery or a dental operation is needed
What is the outlook (prognosis)?
- For sudden episodes of allergic angio-oedema: In most cases they are not severe or life-threatening and will usually clear in 1-3 days. However, recurrences are common and the severity of each episode can vary. Some episodes are severe and life-threatening, especially if the angio-oedema is part of an anaphylactic episode.
- If your angio-oedema is due to a non-allergic reaction to a medicine, then the episodes of angio-oedema can get more severe if the medicine is not stopped.
- Idiopathic angio-oedema often has a waxing and waning course. The severity of each episode can vary. If you have chronic urticaria then treatment for this may help to prevent some episodes of angio-oedema.
- Hereditary angio-oedema can vary in severity.
Dr Tim Kenny
Dr Hayley Willacy
Dr John Cox