Fainting and Anaphylaxis: clues which may help you tell the difference
(this guide is not perfect; you need a doctor if in doubt.)
Can remain low lying down
Normal when lying down
Other features which may be present
Tummy pain or diarrhoea
The person has probably fainted before.
(Some people do faint, others don't.)
People who are allergic to foods often notice the effect in seconds, and their life may be in jeopardy within a few minutes. Sometimes a reaction takes much longer to start, an hour or so, but can still be extremely serious. Improvement can also happen quickly, especially with the right treatment. A few people then have a second wave of anaphylaxis, so people who have had a serious anaphylactic reaction to nuts should be observed medically for about six hours or overnight.
Fortunately there is a highly effective treatment: adrenaline (epinephrine). But adrenaline (epinephrine) needs to be given as an injection, and is dangerous if used incorrectly. If you need to have adrenaline (epinephrine) available for yourself or someone in your family, it is important that you and anyone else who may have to give the adrenaline (epinephrine) should be properly trained.
It is possible for anaphylaxis to be mild and to need little or no treatment. You would not think so from most of the information you read. Of course a life-threatening attack of anaphylaxis may look mild in its early stages, so you need to go for medical help just in case, and need to have the emergency treatment immediately available in case things start to go more badly wrong. In most cases it is better to err on the side of treating anaphylaxis early rather than to leave treatment rather late. But the fact is that many people get over anaphylaxis even without treatment.
The fact that previous anaphylaxis has been mild does not guarantee that it will not be dangerous in future. Most sufferers with mild attacks do seem to have relatively mild ones if they occur again. But deaths have occurred in people who had only mild attacks before. The answer is to be prepared.
What happens in the body during anaphylaxis?
Anaphylaxis happens when the body makes the wrong kinds of antibody, a kind
called immunoglobulin E (IgE for short) to protein in our food
or to something like a drug. IgE sticks to cells in our bodies (mast cells
and basophils) which can release substances which have powerful effects on
our blood vessels and air passages. When the same protein or drug reaches the
IgE on the cells, these substances are released, causing blood vessels to
relax, which makes them leaky and can cause swellings and a fall in blood
pressure. At the same time they can make the breathing passages become
Histamine is one of these substances released from the cells. Antihistamines are medicines which stop histamine from working. So you might think that they would be good for nut allergy, and so they can be when the reaction is mild. But as tablets they take about an hour to get into the bloodstream properly, and this is far too slow to save lives in serious reactions.
Antihistamines also don't prevent all the effects of
histamine, for example effects of histamine on the heart, in serious
reactions. Older antihistamines made people drowsy, which is
dangerous if you have to drive. So it could add to your danger if you take
one and then drive to get medical help. Insist on a modern antihistamine
which does not make you drowsy.
Older antihistamines made people drowsy, which is dangerous if you have to drive. So it could add to your danger if you take one and then drive to get medical help. Insist on a modern antihistamine which does not make you drowsy.
More importantly, histamine is not the only dangerous substance released during anaphylaxis. The same cells with IgE antibody on their surface release many other substances which can be just as dangerous. Antihistamines do not protect you against these other substances. This is another reason why antihistamines used alone will not save life in some really serious attacks of anaphylaxis.
Fortunately, adrenaline (epinephrine), the standard treatment for life-threatening anaphylaxis, works against all the most dangerous aspects of anaphylaxis, not just those caused by histamine.
What is the best treatment for anaphylaxis?
Although there are several important treatments, by far the most important
There is one drug which will work against all the effects of all the
dangerous substances released in anaphylaxis. It is adrenaline
(epinephrine). For serious attacks, it is a vital treatment. You need to
inject it; inhalers may no longer be an option.
Name of injection kit
|Epipen||USA, Europe||Adult 0.3 mg|
Child 0.15 mg
| Dey Laboratories
|Anapen||UK||Adult 0.3 mg|
Child 0.15 mg
|Lincoln Medical Limited, UK||Identical drug & dose to Epipen. Easy to use.|
|AnaKit||USA||2 doses of 0.3 mg: other doses possible||Bayer||Long-established. Red box also contains antihistamine tablets and flimsy tourniquet (for bee or wasp sting).|
|Anaguard||USA, also available elsewhere.||As AnaKit||Bayer||Syringe as AnaKit , pen-like container is compact and strong, no tablets or tourniquet.|
|Min-I-Jet||UK||1 mg, other doses possible||IMS, UK||Seems designed more for hospital use.|
The Epipen Jr, which delivers 0.15 mg adrenaline (epinephrine). Supplier in USA: Dey Laboratories, 2751 Napa Valley Corporate Drive, Napa, CA 94558, Tel. 800-755-5560
A note for UK users: (personal view)
The Epipen and the Anapen are available on ordinary prescription in Britain. The Min-I-Jet was, we guess, developed for use in hospitals and clinics rather than by lay people. The Anapen is perhaps the most intuitive to use, and may be least likely to malfunction if not used quite correctly.
An adrenaline (epinephrine) inhaler which was available in the UK and many other countries, the Medihaler Epi, was withdrawn by the manufacturer (3M) because of stability problems, though it had been proved to work. Other inhalers are avaiable in the USA but evidence presented in March 2000 showed them to be ineffective when tested on volunteers. New adrenaline (epinephrine) inhalers may be introduced in the future..
All these devices with adrenaline (epinephrine) are only reliable if you follow the instructions. They can be dangerous if used the wrong way. If you need them it is important that someone teaches you how to use them properly. If you cannot get such teaching (and you should be able to), then make sure you read the instructions with great care.
Adrenaline (epinephrine) cannot help you if you do not have it with you.
Keep the adrenaline (epinephrine) in a clearly marked robust pouch or case so that it is easy to keep with you. Protect it from light and from high temperatures. In hot climates, keep the container out of direct sunlight and overheated locations such as parked cars. For example in a bag of beach things you can keep it wrapped in several layers of clothing, but still rapidly retrievable by tying one end of a cord to the container and the other end to the handle of the beach bag.
How long will the epinephrine (adrenaline) keep? Info based on FE Simons, 2000, in press.
Not forever. Make sure that you check the expiry date on the syringe and make sure that you have a replacement by the time this date comes. It really can lose a lot of its effectiveness if you let it go out of date.
Some manufacturers will let you know when the time comes to replace the kit. But you have to fill in a coupon and send it to them when you get your kit. Otherwise they obviously can't give you this service.
Be sure to follow the storage instructions. The Epipen must not be kept in a refrigerator, and no epinephrine injection device must be allowed to freeze (replace if this happens accidentally, e.g. in a car left in freezing conditions long enough).
Often the adrenaline (epinephrine) solution goes yellow or brown when it is becoming useless, but you can't rely on this. It can also become useless without changing colour. So do take care to follow the manufacturer's storage instructions.
The protective tube for the Epipen is flimsy and disintegrates if carried
about. Robust tubes are available from the Protectube website, at
http://www.Protectube.com/. I've had a look at one of these and it's
certainly a vast improvement. The price is reasonable and shipping charges
are the same outside North America as in Canada & USA. They are made of
Adrenaline (epinephrine) must be protected from light and the original flimsy brown container helps with this. If you use the Protectube you must provide separate light protection for your Epipen, e.g. by keeping the whole thing in a lightproof container or wrapping the barrel in kitchen foil, making sure that it is still readily identifiable as your emergency kit.
What is adrenaline (epinephrine)?
Adrenaline (epinephrine) is a quick-acting hormone. Our body produces it from
two glands sitting just above each kidney. This happens when we meet an
emergency; the adrenaline (epinephrine) makes our heart pump faster, widens
the air passages in the lungs, and tightens up our blood vessels. We get the
well-known feeling of alertness and the feeling of a rapid heartbeat and
tremor which comes from suddenly being in an emergency. Not only does
adrenaline (epinephrine) ready the body and the mind for 'fight or flight',
but adrenaline (epinephrine) also works against all the effects of
So adrenaline (epinephrine) is the body's own natural quick-acting hormone for emergencies. When we inject it from a syringe, we can give more than the body can produce quickly.
This means you get more benefit, but also more side-effects and some dangers. In most people adrenaline (epinephrine) is very safe if you use the right dose in the right way, but it is important to understand what you are being asked to use.
When should I inject adrenaline (epinephrine)?
Some specialists say you should inject adrenaline (epinephrine) for
any reaction. We don't agree.
Our recommendation is the
Only two things cause death: the '2D' RULE
Finally, the '1D' RULE
Adrenaline (epinephrine) inhalers seemed a good option in the past. There was good evidence that they could work, but the inhaler to which this applied has been withdrawn.
In March 2000 Dr. F. E. Simons of Winnipeg, Canada, presented clear evidence at the American Academy of Allergy, Asthma and Immunology (AAAAI) conference in the USA that the current ones do not work, and in October 2000 she backed this up with further detail. Since right now we are only aware of adrenaline (epinephrine) inhalers from one manufacturer, whose products were the ones used in this research, we believe that currently available adrenaline (epinephrine) inhalers do not work and that at best you must never rely on them. We do not currently issue such inhalers to our patients and do not renew the prescriptions of patients who have such inhalers which go out of date.
If you have such an inhaler, we urge you to consult your allergy specialist about it. Please remember that throughout these web pages what we write is not intended as individual medical advice but as information of possible interest to you, and that your treatment should be determined by your own doctor or properly qualified health professional.
In any case, even if they are capable of working, inhalers will only help if you use them correctly. A nurse or doctor should make sure you have got the technique right. Obviously an inhaler won't work if you can't breathe well enough because of your reaction. If your reactions look as if they might be life-threatening then an inhaler alone not adequate; you need an injection kit.
Do I need to use more than one injection of adrenaline
(epinephrine)? Sometimes, in really bad anaphylaxis, someone may
need more than one adrenaline (epinephrine) injection, but nearly always one
injection is enough to save life. Too many injections of adrenaline
(epinephrine) can definitely be dangerous. For example a young man who gave
himself five injections probably died from the injections and not from the
anaphylaxis. So your doctor's advice is vital; you may be able to stand more
or less adrenaline (epinephrine) than the next patient, and your doctor can
give you advice which is right for you.
Some doctors recommend carrying more than one injection dose, and others do not. Some of the injection kits can give more than one dose, but the spring-loaded automatic injectors can only give one dose.
The dose of adrenaline (epinephrine) in the injection kits is usually 0.3 mg for an adult, which is rather low for a really dangerous reaction in a full-sized adult. The reason for this is safety. We know that this dose works in the vast majority of people, but that a few people would get bad side effects from a higher dose. So we recommend this smallish dose because it is the safest overall. But your doctor may be able to give advice more appropriate for you. Hospital doctors would often give 0.5 mg, nearly twice as much. Some would give 1.0 mg, but our opinion is that this is an uncomfortably large dose even for most young adults to give all at once unless the situation is much more desperate than it usually is.
We recommend that the decision on whether you need one or two injection kits is one for which you need your doctor's advice.
How long will an adrenaline (epinephrine) injection
carry on working after I have injected it? Many doctors say that the
adrenaline (epinephrine) will wear off in 15 to 20 minutes. This would often
mean you might not get to a hospital in time, e.g. if you reacted whilst on
holiday. The published evidence suggests that adrenaline (epinephrine)
injected under the skin (subcutaneously) works for much longer than this,
perhaps longer than the 150 minutes for which one set of research workers
carried on measuring adrenaline (epinephrine) in the blood of their
volunteers. Our feeling is that the same would be true for injections in to
the muscle at the side of the thigh (intramuscular).
The bottom line is that single doses from the widely used injectors have an excellent record for patient survival. So in practice one injection does seem to do the job and enable people to get any extra help they need under nearly all circumstances.
But if you are in a remote area, you should carry more than one dose.
What are the side effects of adrenaline
In the doses we recommend, trembling, palpitations (feeling your heart
beating fast), and a feeling of tension or anxiousness. These are normal
effects of the adrenaline (epinephrine) and soon wear off. Higher doses cause
an extremely unpleasant feeling and may be dangerous to the heart.
If you have high blood pressure, or an abnormal heart rhythm, or narrowing of the coronary arteries, or if you are treated for depression with an unusual medicine called a monoamine oxidase inhibitor, special caution is needed with adrenaline (epinephrine), and a specialist should advise you.
Is adrenaline (epinephrine)
being prescribed far more often than necessary?
Deaths of young children from anaphylaxis are very rare. Yet huge numbers of
children now go around with adrenaline (epinephrine) injection kits. All
medical treatments have side effects and dangers. Although adrenaline
(epinephrine) injections given correctly are remarkably safe, they may be
more dangerous than the disease if the risk to life from the disease is small
A group of paediatricians in the UK suspects that the dangers of adrenaline do indeed outweigh the benefits. They are planning to find out how many children with food allergies under the age of 16 years actually die or nearly die from anaphylaxis per year. Their aim is to find better rules for deciding whether a child's life is in danger, so that far fewer children with allergies will need adrenaline kits.
If such research succeeds, vast numbers of parents would be able to heave a sigh of relief. Their families and their children's teachers and carers would be spared unnecessary fear and the burden of keeping and using adrenaline.
It is amazing but true that we don't have even remotely reliable figures for the number of deaths and near-deaths from food allergy. This is because of the way death certificates are filled in and turned into statistics, and to some extent because of the low importance given to allergy in the training of doctors. Without this knowledge we can't tell parents how the risk without treatment balances up against the risk of treatment. Widespread prescription of adrenaline is recent and we don't know the risks as well as we would like. What we are doing now is the best we can manage with inadequate information. Better information offers a definite hope of better treatment, which, according to the research group, could mean much less treatment.
In Leicestershire there seem to have been three children who have died from nut allergy in the last five years, and we found out about each these through newspaper reports or by chance. So there may well have been other deaths we do not know about.
Parents with nut-allergic children tell me that they would happily see tens or hundreds of thousands of children given adrenaline (epinephrine) to save one child's life. So even just taking our local experience, it looks as if we are doing what parents want.
Since we know that national statistics on deaths from food allergy are very unreliable, they may be a big underestimate, so the risk may be greater than we know.
People who have died from nut allergy have often not had particularly life-threatening reactions before. This means that we have to regard almost all nut allergy as life-threatening. We knowingly prescribe adrenaline (epinephrine) for children in whom we are perfectly aware that the risk is very low. We say so to their parents. We prescribe adrenaline because this is what parents in general want and on balance it is what we feel we would want for our own children if we faced the same problem.
Not infrequently we find ourselves under pressure from a parent to prescribe adrenaline when we feel that the risk really is far too low to justify that; these discussions are difficult because of the great uncertainties.
Personally, I regard the prescribing of an adrenaline kit as an evil, but the lesser of two evils in an inadequately understood situation. If there were a safe way of prescribing less, I would welcome that with great relief.
But there are more disadvantages. Firstly it is a fact that not every adrenaline kit prescribed will be used correctly. People are simply not infallible. Although we must do everything we can to minimise this risk, it is no good ignoring it. Even in our own clinic, where we lay tremendous stress on training the adults in charge of a child repeatedly and where we are lucky to have facilities for this which most clinics don't have, it is a fact that distressingly many people make serious mistakes when we test their knowledge a couple of months later.
People have injected adrenaline into their thumbs (dangerous), have used the training dummy injectors on the wrong parts of the body, or have failed to give an injection because they didn't do what we had taught them. Elsewhere, there have been deaths because people gave too high a dose, either by giving too many injections or by giving too big an injection (impossible with the present UK kits). Doctors have mistakenly injected adrenaline into a vein at a strength which is only safe when injected into muscle or skin.
The risks from these mistakes are part of the risks of using adrenaline, and we must weigh them in the balance when we prescribe it.
The fact that you have been told you need the adrenaline is a constant reminder of the risk of death. If that risk is in fact vanishingly small (for example much smaller than the risks from accidents, infections, or drug abuse), then the very fact that you have the adrenaline may harm you and your family by imposing another stress on your life on top of the others which you may face.
The cost of repeated and duplicated prescriptions and the time of your specialist and family doctor and nurses at clinics and at school is not trivial. These funds could otherwise be spent on other health care.
For all these reasons we should not take the view that we may as well prescribe adrenaline just because 'at least it can't do any harm'. It can and it does.
But if the risk of not having adrenaline is bigger than the risk from having it then we should offer adrenaline. We should then not be swayed by prejudice against the treatment, perhaps based on the fact that 'we never did it before' (when there was not so much nut allergy) or on under-reporting of the dangers of nut allergy because the medical statistics are unreliable.
The job of doctors and experts is to establish the facts as well as possible, to explain these clearly, to make recommendations where we feel that known facts justify these, but to make final decisions after letting parents tell us what their priorities are. The reason for this is that such decisions are never a question of fact alone, but necessarily involve value judgements. Experts may be no better than lay people when it comes to these. Parents and patients have a right to have their views taken into account.
The authors seem overconfident that we can count the number of deaths from anaphylaxis accurately. Our information is that Death Certificate information is not accurate for this, and that not all deaths will become known to paediatricians. Over-busy paediatricians may not be as reliable at reporting incidents as the researchers hope. Standards of expertise and practice vary so much that treatment is an inadequate indicator of severity.
Most important of all is this question. How many children is it worth issuing with adrenaline kits to save the life of one child? I have debated this with groups of parents of nut-allergic children. Always they have come up with figures which astonish me, typically in the region of 100,000 children issued with kits to save one life.
Of course these parents would change their minds if it became clear that the risk of death from adrenaline was greater than the risk of death from the allergy. But this argument is likely to be difficult, because both figures should be very low.
People will reject the argument that deaths are unimportant because they are few if safe and acceptable measures can prevent them. Society provides other examples of public insistence on safety measures which seem hard to justify on quantitative grounds.
When it comes to judging the psychological disadvantages of having adrenaline around, doctors really cannot make the decision without serious discussion with parents, and even with the children.
The most important reason why there is an argument is that we do not know as much as we need to know. Research to establish the facts is necessary.
Doctors must recognise the value judgements involved, and the right of parents in making those value judgements. As in the case of other difficult medical decisions, this will not be simple because both doctors and parents vary in their personal qualities and judgements. There will always remain instances of disagreement. But exercising humanity and good sense does not mean that a doctor must always give way to a parent.
Debate fuelled by careful research is necessary and healthy.
Remember that this or any web page cannot give reliable individual advice. Your own expert medical adviser will be able to give you better individual advice. You may however find the page useful for discussion.Before adrenaline (epinephrine). (But do not delay adrenaline / epinephrine).
When the immediate emergency is
Sometimes it is not certain that the patient had anaphylaxis. There may be
other explanations if the features were not typical. There are at least two
useful tests which can be done during the hours after the emergency. One is
to take a clotted blood sample (the doctor will know what this means) and
test for sormething called 'mast cell tryptase'. The other is to collect
urine for a few hours (the exact timing is not always regarded as all that
important, but emptying the bladder immediately after the reaction and then
collecting for 2 or 4 hours is fine) and test this to measure something
called 'methylhistamine' (this is what histamine turns into when your body
Referral to a specialist is necessary if the cause of your anaphylaxis is not known and you have not seen a specialist. Whether or not the cause is known, a specialist will be able to help you to guard against future attacks.
Some medicines can make
anaphylaxis worse: Beta blockers
Beta blockers are medicines used to treat high blood pressure, some heart
rhythm problems, and some other conditions. Unfortunately they can make
asthma worse, even when they are only used in the form of eye drops for an
eye problem called glaucoma (increased pressure in the eye).
Anaphylaxis can also be made worse by beta blockers, and beta blockers will make treatment with drugs like adrenaline (epinephrine) less effective. In fact some patients who have only urticaria or angioedema (angiedema, angioneurotic edema) when off beta blockers will collapse with a drop in blood pressure when they are on beta blockers. So beta blockers can turn bearable skin reactions into dangerous reactions with shock.
Here are some references to the medical literature on this:
Address: (since November 1997)
2 Clockhouse Rd
Telephone: 01252 542 029
Fax: 01252 377 140
The Anaphylaxis Network of Canada site is also of interest even if you don't live in Canada.
Title: "Life-threatening Allergic Reactions. Understanding & Coping with Anaphylaxis"
Dr Deryk Williams, Anna Williams, Laura Croker.
Publisher: Piatkus, UK.
Year of publication: 1997
Paperback. £ 7.99
Co-written by a General Practitioner, a psychologist and a writer specialising in health matters, this book can be read in an evening and is full of useful information, anecdotes and ideas. There are a few errors. As with all such sources of information, including the web page you are reading now, check matters of importance with the doctor who is advising you locally. Covers the range of common causes of anaphylaxis, for example not only nut allergy but also latex allergy. Rather extensive discussion of the psychological impact. Whilst this is a real enough problem, I would personally recommend contact with a self-help group such as the Anaphylaxis Campaign rather than professional psychological help for the vast majority. It is also important that professionals including doctors and nurses do not needlessly heighten your anxiety. With anxiety as with other things, prevention is better than cure. According to its front cover this book is recommended by the Anaphylaxis Campaign.
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Telephone: 0207 833 3034
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