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Angioedema: what is it?

Angioedema is an at best an uncomfortable and disfiguring type of temporary swelling, and at worst a life-threatening one. It is very similar in many ways to urticaria, with which it often coexists and overlaps. Although both conditions may result from allergy, mostly this is not the case when they keep happening without apparent cause.

The swellings happen especially in the lips and other parts of the mouth and throat, the eyelids, the genitals, and the hand and feet. If you get angioedema one or both of your lips may look like sausages, your eyelids may be nearly or even completely closed by swelling, or your tongue may be so swollen that you have difficulty speaking.

Angioedema is life-threatening if swelling in your mouth or throat makes it difficult for you to breathe. Less often the sheer amount of swelling means that so much fluid has moved out of your blood circulation that your blood pressure drops dangerously. Fortunately only a small minority of people with angioedema get these dangerous features, but if you are one of them you need detailed instruction by a specialist in the necessary safety precautions, and special care to make sure that some undiscovered cause of your trouble has not been overlooked.

Whatever the reason why you get angioedema when others don't, the way angioedema comes about is in the end the same in all cases. Small blood vessels deep in your skin or gut leak watery liquid through their walls, causing a swelling. This is very similar to the way hives (urticaria) weals come about; they just happen closer to the skin surface. So it is not surprising that angioedema and urticaria often go together.

An old and misleading name for angioedema is 'angioneurotic oedema'. What this was intended to mean was that people thought that nerves were involved. A problem with this word is that ignorant people associated this with the word 'neurotic', and assumed it had something to do with anxiety or mental instability. This is nonsense. Blaming a physical condition like angioedema on your mental state is, quite literally, 'adding insult to injury'. Angioedema is a physical illness with physical treatments, and is not due to 'nerves'.

Acute Angioedema

Angioedema is called 'acute' if it lasts only a short time (minutes to days) and does not keep coming back. A typical example would be angioedema caused by eating shrimps or prawns if you are allergic to them. However, acute angioedema can also be caused by the same things which cause chronic angioedema.

Chronic Recurrent Angioedema

If angioedema keeps coming back over a long period, it is called 'chronic angioedema'. The word 'chronic' simply means that it lasts a long time.

Chronic recurrent angioedema most often does not have a cause which we can discover. Doctors, in their mystifying way, like to call this 'idiopathic' angioedema. The word simply means 'its own cause', which is a piece of laughable stupidity we doctors are stuck with. What doctors really mean when they use the word 'idiopathic' is that they don't know the cause. The rest of this page is mostly about chronic recurrent angioedema.

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Different kinds of angioedema

Acute angioedema

Angioedema which happens only once, or just when you encounter something you are allergic to

Most people are familiar with the hives (nettlerash, urticaria) or swelling which can happen when somebody who is allergic to shrimps or strawberries eats them. These days a distressingly large number of parents find that one of their children gets swelling (angioedema) or other symptoms of allergy from eating or touching nuts.

Usually your family doctor will be able to sort this out, though if the swelling looks as if it was or might in future be life-threatening you wil need to see a specialist. Angioedema is also a feature of anaphylaxis, a severe allergic reaction affecting more than one part of the body and potentially threatening life in several ways.

The list of things which can cause acute angioedema is enormous, and new causes are always turning up. Prominent causes are:

  • Foods: Egg, fish, nuts of all kinds as well as sesame seed and some other seeds, strawberries, seafood such as shrimps and prawns, and many other foods. Less common causes include celery, cumin, Chinese water chestnuts, and a host of others.

  • Medicines. Aspirin is by far the most prominent example, along with 'nonsteroidal anti-inflammatory drugs' (NSAIDs) These are painkillers often used for rheumatic diseases or as substitutes for aspirin. But an enormous host of other medicines can do it.

  • Natural rubber latex such as that in medical gloves and catheters, but also in balloons, contraceptive devices and even to some extent rubber bands. If this is your problem you may have similar reactions to banana, avocado, kiwi fruit, chestnut and a range of other fruits. You need to see a specialist to know how to be safe if you need dentistry or surgery, or other medical procedures. If you are an adult, you are likely to be a nurse or someone else who uses latex products at work. Children with latex allergy are likely to have this because of an illness which needed a lot or surgical treatment and use of catheters, such as spina bifida.

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Chronic recurrent angioedema

Angioedema which keeps happening

This can be the same as acute angioedema which just keeps happening. In other words, sometimes the cause can be discovered. More often, unfortunately, the cause remains undiscovered, which means that it is considered to be:


Angioedema without a discoverable cause

Chronic recurrent 'idiopathic' angioedema

Of course there is a cause for your swelling. It is very aggravating to find that your family doctor and your specialist can't tell you what it is and so enable you to avoid it. But that is the reality for vast numbers of fellow-sufferers. We must hope that more medical research will make us doctors more successful in helping more people with angioedema.

The fact that different people with angioedema respond so differently to treatments means that they must have different forms of angioedema. This may help us in the future to clear up the mystery about at least some of our patients.

Meanwhile, the best you can do is to eliminate all the discoverable causes you can. We hope that this web page will help some people to do so.  

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Aspirin hypersensitivity as a cause of angioedema

If you are hypersensitive to aspirin, you may get swelling which can sometimes be life-threatening, not only from aspirin, but also from other painkillers such as ibuprofen and other drugs of a type also used for rheumatic conditions. The puzzling bit may be that you don't take aspirin and still have angioedema. Things in ordinary food and drink may be triggering your angioedema.

One way of checking whether aspirin-like things in food might be causing your swellings is to see a dietitian, who can tell you how to avoid salicylates, benzoates and azo dyes. Although the role of these things is controversial in some ways, some people seem to find the explanation for their attacks of swelling in this way, and seem to stay well if they stick to the diet. My own experience is that if your trouble comes on as badly as ever after you have tried the diet for at least two days, then the diet is a waste of time and you should abandon it. If the diet does seem to work, it is often an excellent idea to break the diet a few times (something which usually happens anyway by mistake or because you sometimes get fed up with the diet) to see if this brings the trouble back, but consult a specialist before you try this.



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Other medicines which cause angioedema

Medicines can cause angioedema in a lot of different ways; true allergy to the medicine is only one of them.

High blood pressure tablets called ACE inhibitors can in just a very few people cause angioedema which may be devastatingly severe, even fatal. They work against high blood pressure because they inhibit an enzyme which is necessary to produce a substance which pushes the blood pressure up. But this same action seems to inhibit the breakdown by enzymes of substances in the body which can make blood vessels leaky. Why this gives only a few people angioedema is still a mystery. If this affects you, your treatment needs to be changed.

Beta blockers are medicines which are useful for high blood pressure and for other problems. They do this by blocking some of the effects of adrenaline-like (epinephrine-like) substances in the body. But they can sometimes make any kind of angioedema, urticaria (hives) or anaphylaxis worse. This is surely because the same adrenaline-like substances are an important part of our defence against too much leakiness of the blood vessels. At any rate 'beta blockers' can turn mild urticaria into a much more severe problem, and can do the same with other allergy-like changes such as angioedema, and for that matter asthma.

Other medicines may cause angioedema if you have a drug allergy to them. This can happen with a huge number of medicines, though more commonly such drug allergies cause rashes rather than swellings.  


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Deficiency of, C1 inhibitor, a protective protein in the blood

Hereditary angioedema is a very rare kind of angioedema, which runs in families. It comes about if you are short of a normal blood protein, called C1 inhibitor, or if you have inherited genes which make a C1 inhibitor protein which does not work properly.

C1 inhibitor is also called C1 esterase inhibitor, but the shorter name is better, because the esterase only refers to something which happens in lab tests, not in the body. Hereditary angioedema (HAE) used to be called 'hereditary angioneurotic edema' (HANE), but there is no evidence it has anything to do with nerves, and the term was not intended to mean that affected people were 'neurotic' but was misinterpreted that way.

Although this is rare, it is most important to know if you have this kind of angioedema. Two important clues to this are:

  • Attacks of bad tummy pains which come and go in waves and don't have another obvious explanation.

  • Unexplained swellings or tummy pains in other members of your family, even if these swellings or pains are not nearly as bad as yours.

The tummy pains happen because the same kind of swelling sometimes blocks your intestines, causing a bad kind of pain called 'colic', which comes in waves. If no-one suspects you have C1 inhibitor deficiency, surgeons might want to operate on you to find the reason for your severe pain. But if the reason is C1 inhibitor deficiency, at most they will just find swelling, and an operation won't help. More often the operation is done at a time when you are well, and then the surgeon will find nothing wrong at all. So having the diagnosis made can save you unnecessary surgery. Of course if you do have this condition you can still get all the same illnesses as anyone else, and you might really need an operation. But even then the surgeon and the anaesthetist will certainly want to know about your C1 inhibitor deficiency.

Other people develop a shortage of C1 inhibitor for other reasons, and get the same symptoms. They have acquired C1 inhibitor deficiency (i.e. acquired during life rather than inherited). This usually comes on much later in life than the hereditary form and definitely needs some special investigations if the cause is not obvious. Like everyone else with C1 inhibitor deficiency, people with this form need to see a specialist.

The treatment for C1 Inhibitor deficiency is quite different from that of most other angioedema:

  • Adrenaline (epinephrine) does not work well as a treatment; in fact it generally seems not to work at all. However, specialists may still give you adrenaline (epinephrine) just in case it helps a bit.

  • In emergencies or situations which are likely to trigger the angioedema, injections of C1 inhibitor are available, and useful. Fresh blood plasma can also help by replacing the missing inhibitor.

  • Some drugs which inhibit some of our normal protein-splitting enzymes are useful in preventing this form of angioedema. Tranexamic acid and epsilon-aminocaproic acid are the names of these drugs. Sometimes they are even useful for angioedema without a known cause. These drugs are more commonly used to treat heavy menstrual periods, so they are not such rare drugs and we know a lot about their safety. The main side effects are tummy upsets, but far from everybody gets these and reducing the dose may solve the problem. If you take them long-term you can get little opaque deposits in your eyes, so make sure you know what to do to spot this happening if it does affect you; the manufacturer suggests regular eye checks and also blood tests to check your liver.
    Our eye specialist does not agree with the need for regular eye checks and thinks it is enough to get your eyes checked if you notice haloes round lights, more trouble than usual from bright sunlight, or less clear vision. But bear in mind that in the UK National Health Service eye doctors are heavily overworked and are forced to cut out work not seen as absolutely essential.

  • Steroid hormone tablets (anabolic steroids), of the particular kind some athletes have misused to enlarge their muscles, help some people with C1 inhibitor deficiency. But their possible side effects mean that a specialist (whom you should be seeing anyway if you have this problem) should be supervising the treatment. If you are female, an important point is that they are like male hormones and may cause some changes which you would find unwelcome. So in girls and women we are especially careful in the way we use these steroids, to make sure the side effects are not more troublesome than the illness. They can also cause serious liver trouble, although in practice this does not commonly seem to be a problem; the safeguard is to have blood tests periodically to make sure your liver is safe.

    By the way, these steroids are completely different from the much more common kinds of steroid tablet, usually prednisolone or prednisone, which doctors often prescribe for really bad asthma and a wide range of illnesses including very bad urticaria or angioedema. These also have side effects, but quite different ones. Whatever treatment your doctor gives you, it is reasonable and right for you to ask about the side effects so that you can satisfy yourself that the inevitable risks of any medical treatment are reasonable in the circumstances.

A website on Hereditary Angioedema

The Hereditary Angioedema Association Home Page

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Other kinds of angioedema

This web page cannot tell you all the answers, though we hope that what you see will provide useful clues to some people. Remember that a web page is no substitute for seeing a doctor with the appropriate expertise. On our page on Other sources of information you will find guidance on how to find a specialist, but your family doctor may be your best source of advice on whether a specialist is needed and who might be a good one.

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Not angioedema: is your swelling something different?

There are other things which can cause swelling, but because angioedema is so much commoner than these, the other kinds of swelling are sometimes mislabelled as angioedema.

The four clues which often give the game away are:

  • Treatments don't work. However, a very few people with true angioedema don't seem to benefit from any of the treatments.

  • The swelling never goes away completely.

  • The swelling is always in the same one place. This usually means there is some other disease process in the place where the swelling occurs.

  • You have other symptoms of illness in addition to your angioedema. Though people with angioedema often feel unwell whilst they have the swelling and for some time afterwards, they feel well on other occasions. If there seems to be more than this to it, ask your doctor.

If you have any suspicion that your swelling may not be true angioedema, discuss this with your doctor.

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This section is still incomplete.

The treatment of angioedema is in many ways very similar to the treatment for urticaria. You may need adrenaline (epinephrine) inhalers or injections if you have swelling in your mouth or throat, so that you have difficulty in breathing or if this seems a danger. In the rare form of angioedema caused by lack of C1 inhibitor .adrenaline seems not to help particularly and antihistamines are no use, though people still try adrenaline : other treatments are more important in C1 inhibitor deficiency.

Avoid the cause if you or your doctor can find one. Allergy to nuts, latex, other foods, and medicines can all cause angioedema. Avoiding medicines which cause angioedema in ways other than allergy may solve your problem. Aspirin hypersensitivity for example is not a true allergy, but is important and means you also have to avoid some other medicines and may have to avoid some foods.

Antihistamines often help tremendously in preventing swellings, and it may be worth your while to take one regularly. Make sure you get one with no unnecessary side effects. If you take them by mouth it takes about an hour before they get into your bloodstream.

But in some people antihistamines don't help the angioedema at all. This is very frustrating. Sometimes when this happens tablets used for hereditary angioedema (tranexamic acid and epsilon-aminocaproic acid) help when antihistamines have failed. We don't know the reason for this, but we are grateful when it works.

If there is any suggestion that your angioedema might be in any way dangerous, see a specialist. The danger usually comes from difficulty in breathing. If you feel an attack of swelling is not under good control, or might slip out of control, get yourself to a hospital with emergency facilities.

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If you spot mistakes or have questions, please e-mail me .
This page is maintained by Martin Stern
Page launched: 21 January 1998, updated 2 February 1998 & April 1999 (C1 inhibitor deficiency) & 14 & 15 Jun 99 (typos, mention of non-preferred terms CI esterase inhibitor & HANE). 11 Oct 2000 (Hereditary Angioedema Association Home Page URL changed). 25 Apr 2001 link to urticaria & links from urticaria.

Copyright © 1998, 1999, 2000, 2001 Martin A. Stern