by Jim Wright AM, MD, FRACS, FACS (Dr Wright is a retired medical practitioner and a member of the Hunter Valley Branch of the Amateur Beekeepers’ Association of NSW)
The first recorded fatality from stinging insect hypersensitivity probably occurred in Egypt in 2621 BC. The victim was King Menes, the first king of the first Dynasty, founder of the city of Memphis, and diverter of the Nile. An account of his death is found on the walls of his tomb. There is some ambiguity in the translation of the heiroglyphics as the symbol for a wasp is very similar to that for hippopotamus. However, as no hippopotamus stings have been recorded since that time, the former translation seems secure! Dr David Sutherland, Newcastle Immunologist.
There is widespread fear of bees in the community. This not only because bee stings hurt, but because many people believe that they are allergic to them when they swell up after a sting. The fact is that true allergy is relatively rare, estimated as 0.3 to 0.5% of the population. Nevertheless, it is a serious problem, accounting for approximately one death per year in Australia and 40 per year in the USA .
It is the purpose of this paper to discuss the two types of effects of bee stings; those due to the toxic or poisonous properties of bee venom itself, ( the normal response to a sting ), and, those due to allergy to the venom ( the abnormal response, allergy or hypersensitivity).
Fatality solely due to the toxic effects of the venom itself is extremely rare, the lethal dose being estimated as 192 stings per kilogram body weight, which translates as approximately 1400 stings for the average male and 1100 for a female. However, death has been recorded after as few as 50 stings. For what it is worth, 500 beestings equate to a rattle snake bite!
In contrast, in a person truly allergic to bee venom a single sting is potentially fatal.
So, what is the difference, why are beestings so dangerous to some people while relatively harmless to the vast majority?
What is allergy?
It is a word of Greek origin meaning other work, or, in this context, other reaction. The words hypersensitivity reaction have a similar meaning, while anaphylaxis is used to describe the most extreme form of allergic or hypersensitivity response.
When foreign protein substances are taken into the body, either by mouth or injection, a defence reaction is set up and antibodies are formed. These are our own proteins designed to lock on to the specific foreign protein and neutralise it when the body is next exposed to it. This is the basis of immunisation, a wonderful medical tool which has eliminated smallpox from the world. It is the normal response which is responsible for the experienced beekeepers well known tolerance or immunity to bee stings. These good antibodies are known as Immunoglobulin G, or IgG.
In the allergic person, the response to the foreign protein is different. Instead of IgG being produced, another antibody, IgE results. It adheres to some blood and tissue white cells, awaiting further exposure to the offending protein, called an antigen. When this eventuates, the antigen reacts with the IgE antibody and the white cell to produce a toxic and dangerous substance called histamine which produces the physiological effects we know as an allergic response.
Thus, the first exposure to the offending protein, in our context one or more of the proteins in bee venom, may produce no more than the normal reaction to the toxin itself, but subsequent stings result in increasingly severe reaction, a crescendo effect due to the production of more and more IgE and histamine. In the extreme, or anaphylactic reaction, the bronchial tubes go into spasm, narrow the airways causing difficulty breathing, the blood pressure falls, the victim is in shock and can die.
Allergy is, however, notoriously unpredictable. It is not unknown for such an anaphylactic reaction to result from the first apparent exposure to the antigen. In contrast, decrescendo or allergic reactions of decreasing severity have been recorded, and even previously immune beekeepers have been known to develop allergic symptoms much later.
One may well ask why do some people develop good IgG and others a predominance of bad IgE? This is unknown. It is known that some protein antigens are very prone to set up the production of IgE. There are several of these highly antigenic proteins in bee venom.
It is also recorded that people with asthma or eczema, conditions involving the immune system, are more at risk of developing allergy to bee venom. The members of the families of beekeepers have a higher incidence of allergy than the rest of the population. It is suggested that this is due to contact with repeated small amounts of bee products from body contact and clothing which sensitise the person by provoking the production of IgE.
What is in bee venom?
It is a complex mixture of chemical substances including enzymes, peptides (protein derivatives), highly active amines including histamine itself and (nor)adrenaline. The enzymes hyaluronidase, phospholipase and acid phosphatase are highly allergenic.
What is the normal reaction to bee venom itself?
It hurts! One needs only to see a child stung for the first time to appreciate how much it can hurt. The immediate vicinity of the sting then swells over the next few hours, and the softer the tissue at site of the sting the more it swells, eg forearms, face and (God forbid) the genitals.This may last several days, turn a dull red and become quite itchy.
Provided the swelling is confined to the vicinity of the sting and is relatively short lived, this is not an allergic reaction.
What is an allergic reaction?
There is a wide range of effects, local and generalised, and these have been artificially categorised into four grades:
Grade I is a local response like the normal effect of the sting, but the swelling is more extensive, angry, very itchy and lasts much longer.
Grade II consists of the same local effects plus a generalised reaction with swelling beyond the site of the sting. A whole limb may swell, or the face and lips and eyelids swell after a sting on the foot. There may be a generalised rash, often urticarial with itchy wheals.
Grade III is the same as grade II with the addition of difficult breathing due to spasm of the bronchial tubes.
Grade IV is all of the above plus a dangerous fall in blood pressure (shock), collapse and even death.
Beekeeper’s immunity
Every beekeeper knows that stings hurt less with repeated exposure. Some even try to pretend that they don’t hurt at all. The truth is probably nearer to what Laurence of Arabia is supposed to have said the important thing is not minding that it hurts! Certainly local reactions are much less severe and more short lived. This is due to the good IgG antibodies neutralising some of the toxic contents of the venom. Tests on beekeepers show high levels of serum IgG, but two out of three also have higher than normal levels of IgE which is capable of producing adverse effects. Presumably it is the balance between levels of protecting IgG and potentially offending IgE which determine the outcome of a sting. This explains two observations, firstly why some beekeepers note greater reaction to stings after a long period without exposure, and secondly why apparently immune beekeepers can develop symptoms of allergy later in life.
There is anecdotal (unproven or hearsay) evidence, quoted in the Australian Beekeeper in 1994 that taking non-steroidal anti-inflammatory arthritis drugs may diminish this established immunity. This is of particular interest because there is also anecdotal evidence, unconfirmed by scientific study, that beestings have a beneficial effect on arthritis. The author has in the past tried to encourage his arthritis suffering wife to get stung, but for some strange reason she has always refused. In view of the information quoted above that there is a significant incidence of covert allergy in the families of beekeepers, it may be that the wife is smarter than the husband.
Treatment of beestings
The normal effects of a sting need no special treatment. (However, this is like the definition of a minor illness or operation, one that somebody else has!). Every beekeeper knows that the sting should be flicked out promptly as the venom sac goes on injecting after the unfortunate bee is dismembered. It has been stated that you have to be quick, most of it is in within two seconds! Itching may be helped by topical applications such as calamine lotion or by taking an antihistamine. Alkaline applications or topical alum (contained in Stingose) may be used.
Severe local reactions can be alleviated by taking steroids (cortisone derivatives). Though even one dose is effective, this powerful drug should not be used without medical guidance .
Treatment of allergic reactions to beestings
The first and obvious measure is to avoid further beestings. For a beekeeper this means seriously considering his options (see below, desensitisation). Even for a non-beekeeper it is not as easy as it seems, for stings occur in the garden, in the swimming pool, the commonest probably being the clover covered lawn, especially in children.
Mild allergic reactions, consisting of excessive local swelling and symptoms, may be treated like a normal reaction with the addition of oral steroid. However, in this circumstance the treatment of this reaction is the least important consideration. What matters more is the possibility of a worse reaction, perhaps life threatening, next time. Thus it is essential to seek specialist medical advice to assess the situation and decide on future action.
Severe allergic reactions require medical attention, which in the extreme case of anaphylactic shock is of the utmost urgency. There is no antidote to bee venom. If the sting is on a limb, bandaging as for snake bite may help slow its absorption, but what the victim needs is an injection of adrenaline, a drug which neutralises the effects of the histamine which is the cause of the trouble. This is a powerful and dangerous drug, the dose is critical, and its use requires medical supervision. For those who know they are at risk, a self injection kit is available and can be used after suitable instruction. Adrenaline is also now available as a metered dose aerosol.
Further doses of adrenaline may be required, as well as ventilatory support and intravenous therapy to maintain blood pressure. This clearly means removal to hospital, if possible by skilled paramedics who are competent to administer appropriate treatment en route.
It is reassuring to reiterate that such severe reactions are rare.
Desensitisation
It is possible to desensitise an allergic person but it requires a prolonged course of injections supervised by a skilled professional immunologist. In earlier years whole body bee extracts were used, but currently bee venom itself is found to be more effective. It is collected by mounting at a hive entrance an electrical device with an underlying perforated membrane, the holes of which just admit the a bee sting. An electric shock stimulates the bee to sting the membrane, the venom is collected beneath it, and the bee survives because the sting can be withdrawn from the hole in the membrane.
This process of desensitisation aims to decrease the levels of IgE, and increase IgG. The method consists of giving at first tiny doses of the venom by injection, followed by slowly increasing doses, always with means of resuscitation at hand lest an unexpected reaction occurs. Side effects have been reported to be as high as 41%, though most are minor. It may take many months, and maintenance doses may be required for some years.
Thus desensitisation is time consuming, and is associated with discomfort and significant risk. It is contemplated only after serious general allergic symptoms, not local reactions. Only expert professionals are competent to advise upon it and administer the treatment.
Fortunately, however, desensitisation works. For protection against life threatening anaphylaxis, it is 100% effective, and only one in 20 people have minor local reactions.
SUMMARY
All that swells is not allergy. Local pain and swelling are the normal response to the injection of bee venom. In a non-allergic person, many stings can be sustained without threat to life, and repeated stings produce a tolerance or immunity resulting in a gradual decrease in reaction severity. This is due to the body’s production of appropriate antibody which neutralises the toxin subsequently injected.
In a person allergic to bee venom, other antibodies are produced in response to stings, antibodies which do not protect but rather provoke the internal release of an even more dangerous substance, histamine. In such people, there is likely to be an increasingly severe reaction to subsequent stings, ranging from extreme local pain and swelling, to rashes, difficulty breathing, fall in blood pressure, shock and death.
There is no antidote to bee venom. The immediate treatment of a severe allergic reaction is the injection of adrenaline, but more drastic measures may be required. Severely allergic people must avoid bee stings or undergo desensitisation therapy.
Fortunately, however, desensitisation works. For protection against life threatening anaphylaxis, it is 100% effective, and only one in 20 people have minor local reactions.
Acknowledgement
Thanks to Dr David Sutherland for references, advice and help in preparation.
This article was published first in the August 2001 issue of The Australasian Beekeeper (ABK) and is reproduced here with the kind permission of ABK Editor and Dr Wright.
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