Allergic Reactions to Insect Bites and Stings

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Me d i c i n eT o d a y PEER REVIEWED ARTICLE CPD 1 POINT

A ll e rgic reactions to insect bites and stings Although sensitisation to insect stings is common, serious life threatening reactions are

not. Initial treatment of patients with allergies to insect stings may involve intramuscular

adrenaline, oxygen and intravenous fluids; ongoing management depends on an

assessment of risk of future reactions for each individual.

ROBERT J. HEDDLE Extent of the problem world. Detailed epidemiological data on Aus- MB BS, FRACP, FRCPA, PhD Overall, 15 to 25% of a population exposed to tralian insect species are currently available only SIMON G.A. BROWN insect stings shows serological and/or skin test for Tasmania. In this State the prevalence of clin- MB BS, DA(UK), FACEM evidence of sensitisation (i.e. detectable venom- ical systemic sting allergy within the general specific IgE). However, only 1 to 5% of the pop- p o pulation is 4.5%, broken down as follows: ulation will give a history of immediate systemic 2.7% for Myrmecia pilosula (the jack jumper Dr Heddle is Director of Allergy, • allergic reaction to the prevalent stinging insects, ant, a type of jumper ant or hopper ant) Department of Medicine, Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2010. and only half of these people will have experi- 1.4% for Apis mellifera (the honey bee) Flinders Medical Centre; Senior • enced life threatening reactions. 0.6% for Vespula germanica (the European Lecturer, Flinders University; • The exact prevalences of sensitisation and wasp, also known overseas as the yellow jacket) and Senior Visiting Specialist, clinical allergy depend on annual sting exposure 0.3% for Myrmecia forficata (the inchman ant).1 Repatriation General Hospital, • r a t e s . 1 Because deaths caused by insect stings can Daw Park, and Women’s and Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2009. be difficult to identify at postmortem, we do not A n t s Children’s Hospital, North know the precise death rate from this cause. Data In mainland Australia, there are 89 species of Adelaide, SA. He has a particular from South Australia and Tasmania suggest that M y r m e c i a ants. M. pilosula (Figure 1) accounts interest in insect venom allergy. it is less than one per million people per year.2 , 3 for most mainland ant venom allergy, with sev- Dr Brown is a Consultant eral larger M y r m e c i a species (Figure 2) account- Emergency Physician, Fremantle Which insects are implicated? ing for much of the rest. Hospital, WA, and Clinical Senior Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2008. Australia has one of the most diverse and poten- Ant sting allergy is a major problem in country Lecturer in Emergency Medicine, tially confusing arrays of stinging insects in the V i c t o r i a , 4 although recognised deaths have been University of Western Australia. He was formerly Director, Department of Emergency • Sensitisation to local stinging insects is extremely common, immediate systemic allergic Medicine, Royal Hobart Hospital, reactions are less common, and deaths following insect stings are very uncommon. Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2007. Hobart, Tasmania, where he • Adrenaline, oxygen and intravenous fluids are the main therapies likely to be effective managed the research program acutely for a systemic allergic reaction. into jack jumper ant sting • Beware delayed and progressive reactions – a period of observation is essential. a l l e r g y , and he is completing a • The prognosis of patients with purely cutaneous reactions to insect stings is usually favourable, PhD in insect venom allergy but deteriorates progressively in those with a history of anaphylaxis of increasing severity. through Flinders University. • The automated adrenaline syringe is a major asset to first aid in the community and has Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2006. wide acceptance; provision of a written action plan is also important. • Patients with a history of immediate systemic allergic reactions with respiratory or hypotensive features should be referred to a clinical immunologist or allergist for advice regarding venom immunotherapy.

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Figure 1. Myrmecia pilosula (the jack jumper ant) is a type of ‘jumper ant’ or ‘hopper ant’. About 10 to 1 2 mm long, it moves in short jerky movements, jumping to attack, sometimes out of surrounding This image is unav a i l able due to bushes. Serological data suggest that it is responsible for about 90% of ant venom allergy in south-eastern c o pyright restrictions Australia. It has well developed vision, is attracted to movement and is extremely aggressive.

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Figure 2. A variety of larger (15 to 22 mm) M y r m e c i a a n t s such as this one (Myrmecia forficata, known in Tasmania Generally, allergic reactions to insect bites and stings can be considered mild if as the ‘inchman’) are often referred to as ‘bull’, ‘bulldog’ they are confined to the skin (erythema, urticaria, angioedema), moderate if or ‘inch’ ants. Common names can be confusing (some associated with gastrointestinal or mild respiratory disturbance, and severe if Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2008. people also refer to jack jumper ants as bull ants), so it is associated with collapse, hypotension or severe respiratory compromise. important to record a description of the insect rather © KEVIN A. SOMERVILLE, 1992 than a name. Expert identification is important when a specimen is available because most species are almost impossible to differentiate by the amateur. • several other ant genera in Queensland, Downloaded for personal use only. No otherincl udusesin permittedg Rhyti withoutdopon permission.era meta ©lli cMedicinea ( t h e Today 2007. confined largely to Tasmania.2 Anecdotally, M . greenhead ant). p i l o s u l a is also a significant problem in the Adelaide Hills of South Australia and around Canberra. B e e s The paucity of reported deaths due to M. pilosula A. mellifera (the honey bee; Figure 3) is found allergy is likely to be due in part to a lack of throughout the continent, particularly in agricul- awareness of the potential fDownloadedor ant sting for personal allergy use to only. tNour otheral ar useseas ;permitted howev withouter, a d permission.ispropo r©tio Medicinenate nTodayumb 2006.er cause death. of deaths due to A. mellifera stings occur in Other species of ants implicated in severe South Australia.3 allergic reactions include: B o m b u s spp. (bumble bees) have become • Solenopsis invicta (the imported fire ant) established in Tasmania and have a venom simi- around Brisbane5 lar to A. mellifera, but cases of anaphylaxis to this Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2005. M e d i c i n eT o d a y ❙ February 2004, Volume 5, Number 2 1 7

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Figure 4. Vespula germanica (the ‘European Figure 5. Paper wasps are found mainly in wasp’ or ‘yellow jacket’) is found mainly in warmer areas of the continent. They are Figure 3. Apis mellifera (the honey bee). The cooler regions. It is characterised by a waist characterised by the long thin waist and presence of a retained stinger in the skin is part that becomes rapidly thicker at the tapered abdomen, and by their ‘spider like’ diagnostic. In very hot weather honey bees abdomen and by its way of holding its legs dangling of legs during flight (pictured here; seek out water and may be encountered close to the body during flight. These insects Ropalidia gregaria). These insects feed on accidentally in open drink bottles (leading are particularly attracted to rotting meat, agricultural pests and generally attack to oropharyngeal stings and airway fallen fruit and sweet drinks (leading to humans only when their nests (often found o b s t r u c t i o n ) . oropharyngeal stings and airway obstruction). under the eaves of houses) are disturbed. new arrival have yet to be documented specific IgE testing alone may be unhelp- Generally, reactions can be considered in this State, probably because of its ful in diagnosis. Clinical correlation based mild if they are confined to the skin (ery- n o n a g g r e ssive nature. Downloaded for personalo nuse kn only.ow Noled otherge o usesf lo cpermittedal speci ewithouts is re permission.quired. © MedicinethemaToday, urti 2010.caria and angioedema), mod- L a s i o g l o s s u m spp. (native sweat bees) erate if associated with gastrointestinal or have been implicated in severe allergic Insect bites mild respiratory disturbance, and severe reactions in South Australia. Despite the high frequency of local reac- if associated with collapse, hypotension tions to mosquito bites, anaphylaxis to or severe respiratory compromise. W a s p s Downloaded for personalin usesec only.t bi Notes other (a suses op permittedposed withoutto venom permission.) is © MedicineWhTodayen initial 2009. management has been V. germanica (the European wasp; Figure very uncommon, but has been reported started, it is also useful to document a 4) is found mainly in cooler regions, and after March fly bites and tick bites. description of the causative insect while P o l i s t e s spp. and R o p a l i d i a spp. (paper Anaphylaxis has also been reported after the patient’s memory is fresh (not just a wasps; Figure 5) are important in warmer exposure to caterpillar spines. colloquial name, which may be inaccurate areas. V. germanica does not appear to or confusing). In addition, key historical have been responsible for dDownloadedeaths thu sfor f apersonalr, M usean only.ag iNon gother th usese a permittedcute r withouteacti permission.on © MedicinefeaturesToday, particularl 2008. y the occurrence of as all recognised wasp sting deaths have Accurate documentation collapse, presyncope, unconsciousness or been confined to warmer areas of New Accurate documentation is essential for breathing difficulty before being seen, South Wales and Queensland where paper the management of patients presenting should be noted. The presence of these wasps are presumed to be the culprits.6 with an acute reaction. The following features suggests a severe reaction, which D i a m m a b i c o l o r has been implicated in basic measurements are critical to fur- may have resolved before the patient was severe allergic reactions inDownloaded southea stfore rnpersonalther use only.management: No other uses permitted without permission. © Medicineseen dueToday to 2007. endogenous compensatory coastal regions. Known as the ‘blue ant’, • skin perfusion mechanisms or self-administration of it is a solitary, ground-dwelling, n a t i v e • conscious state adrenaline. flower wasp. • pulse, blood pressure • respiratory rate Severe reactions C r o s s - r e a c t i v i t y • oxygen saturation (if available) Mainstays of treatment There is minimal cross-reacDownloadedtivity bet wfore epersonaln • usecl only.inic Noal eothervide usesnce permitted of upp ewithoutr airw permission.ay © MedicineVasodTodayilatat 2006.ion (distributive shock), fluid wasp, bee and ant venoms, but frequent obstruction and/or bronchospasm. extravasation (hypovolaemic shock), cross-reactivity between various species of These measurements will be used to upper and lower airway oedema and wasps, between honey bees and bumble assess the need for immunotherapy and bronchospasm are the most important bees, and betweendifferent M y r m e c i a decide whether an adrenaline autoinjector pathophysiological features of anaphylaxis. ant species. Thus, skin and serum venom- must be provided (see below). Thus adrenaline (which physiologically Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2005. 1 8 M e d i c i n eT o d a y ❙ February 2004, Volume 5, Number 2

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Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2000. antagonises the process at all points), vol- until an ambulance arrives. The fluid ume resuscitation and high flow oxygen infusion rate needs to be brisk; a subject Insect stings: managing are mainstays of the management of with severe hypotensive anaphylaxis may severe allergic reactions patients with severe reactions to insect need as much as 60 mL/kg infused under stings. Placing the patient in a supine posi- pressure over 5 to 20 minutes. • Call for help tion is also important to maintain cerebral Note that intravenous adrenaline • Place the patient in a supine position and coronary perfusion until the adrena- boluses (in small aliquots, e.g. in an adult with feet elevated, unless this line begins to work (see the box on this 0.2 to 0.5 mL of a 1:10,000 solution) increases respiratory distress p a g e ) . should be used only if cardiorespiratory • Give intramuscular adrenaline into If airway obstruction occurs, adrenaline arrest is imminent. the anterior thigh is still the most important intervention In an emergency department environ- • Commence high flow oxygen before attempting advanced airway ment, where intravenous access and infu- • Obtain intravenous access; consider manoeuvres such as intubation. Reac- sion preparation can be achieved within fluid resuscitation and additional tions can progress rapidly to complete minutes, we favour administration of an adrenaline if initial response is poor, and airway obstruction and cardiac arrest. infusion of adrenaline at 1:100,000 (1 m g atropine if the patient has bradycardia Thus additional assistance may be in 100 mL). This is administered using an required; activate the emergency medical infusion pump, starting at a rate that will system (phone the emergency number give an appropriate intramuscular dose any reaction with more severe features for an ambulance; 000 in Australia) as by the intravenous route over 30 to 60 (gastrointestinal, respiratory or cardio- soon as possible. minutes (e.g. 30 to 100 mL/hour in an vascular features), give adrenaline and adult). Close monitoring is required and refer the patient to the nearest emergency Adrenaline and IV fluids: aDownloadeddministra tforio personaln th usee i nonly.fus Noio nother sho usesuld permitted be adju withoutsted a cpermission.cording © Medicinedepartment.Today 2010. and dosage to responsiveness and/or occurrence of In most emergency situations, adrenaline any untoward events (hypertension tachy- Beware delayed and progressive will start being absorbed from an intra- cardia, tremor, pallor and nausea). r e a c t i o n s muscular injection before intravenous Beware the patient with ongoing or pro- access can be obtained; usDownloadede the ant eforri opersonalr O usether only. me Nod iothercati ousesns permitted without permission. © MedicinegressivTodaye ana 2009.phylaxis that initially a p p e a r s thigh, through clothing if needed. Sub- Inappropriate intense bradycardia is mild and/or is masked by an intial dose cutaneous injections and injections into an occasional feature of serious sting of adrenaline that will wear off before the the arm are absorbed unreliably. r e a ctions, and intravenous atropine may underlying reaction does. All patients The initial dose of intramuscular sometimes be required.7,8 should be observed until it is clear that the adrenaline is 0.3 to 0.5 mg (0.3 to 0.5 m L Injectable promethazine should be reaction is resolving without treatment of a 1:1000 solution) in adulDownloadedts. In chilfor personal- avoided use only. No as other this uses is anpermitted alpha without blocker permission. and © Medicineand unTodaytil th 2008.e adrenaline (if administered) dren, 0.01 mg/kg is the recommended can aggravate hypotension and cause has been given time to wear off. Patients dose. Alternatively, a simple approach is respiratory depression. with moderate to severe reactions should to use 0.15 mg for children under 6 years Because antihistamines are unlikely be transferred by ambulance to the near- of age and 0.3 mg for older children to have any useful clinical effect in the est emergency department for ongoing (dosages that correspond to paediatric presence of many other anaphylactic management and observed until they versus adult EpiPen dosageDownloadeds). Such d foros personales m useed only.iato Nors, otherwe d useso n permittedot advo withoutcate the permission.ir use. © Medicinehave bTodayeen 2007.symptom-free for at least four can be repeated in 5 minutes if the initial Corticosteroids are very unlikely to hours after the last dose of adrenaline has response is inadequate, or earlier if the have an effect acutely, but may have a been given. They should be instructed to patient deteriorates. role (although unproven) in protracted, seek help immediately should sympt o m s For patients with severe reactions with severe reactions. recur after discharge. severe and/or sustained hypotension, intravenous adrenaline and Downloadedvolume r eforsu personals- M useild only. rea Noct otherions uses permitted without permission. © MedicineDiagnTodayosis 2006. and predicting risk citation (20 mL/kg normal saline or Hart- We use adrenaline for patients with mild Identifying the insect involved mann’s solution, repeated as required) systemic reactions to obtain rapid symp- The circumstances, season, insect may also be needed. Thus secure wide- tom relief. Antihistamines are an alterna- prevalence, nature of the bite or sting, bore (16 gauge) intravenous access as tive and can provide some symptomatic presence of recognisable insect and/or soon as possible and monitor the patient relief for mild reactions. Nevertheless, for stinger and previous sting history are all Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2005. M e d i c i n eT o d a y ❙ February 2004, Volume 5, Number 2 1 9

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important for diagnosis of the insect probably be lethal’ is inaccurate. In delib- This reinforces the concept that reac- involved. The presence of a stinger indi- erate sting challenges and prospective tion risk is best related to the severity of cates a higher probability of the insect studies of accidental field stings, a signifi- the worst previous reaction rather than being a honey bee. If immunotherapy is cant number of people who give a history to the severity of reaction following the contemplated for a patient, the presence of an allergic reaction do not react when most recent sting.1 or absence of specific IgE to likely insects stung again.1 , 9 Overall, the percentage of No one can be totally reassured as a needs to be assessed. Skin sensitivity tests people with a history of systemic reactions significant proportion of deaths from and RAST need to be ordered and inter- who will react to a subsequent sting is 70% stinging insects occur in individuals with preted by someone with specific training for M. pilosula (the jack jumper ant), 50% no known history of insect hypersensi- in the area. This is because of the com- for A. mellifera (the honey bee) and 25% tivity. Prospective studies of the natural plexities regarding species (including for V. germanica (the European wasp). history of untreated insect sting allergy confusing colloquial names), insect dis- The risk of a reaction of any grade is have also been limited in their time- tribution, and sensitivity/specificity of higher in those with a history of severe frame. We know that older people tend the assays. A positive skin test or RAST r e a c t i o n s . 1 , 9 Furthermore, subsequent to have more severe reactions1 , 9 and that alone does not prove clinical reactivity. reactions are usually of either similar or people can have more severe reactions Although a gold standard in clinical lesser severity. In the case of children than previously when they are stung trials, deliberate sting challenges are of experiencing mild reactions to bee and d e l i b e r a t e l y . 7 Thus, for people who fre- limited use in individual cases. Reasons wasp stings, the occurrence of subsequent quent remote areas away from emer- for this include the need for critical care severe reactions is exceptionally uncom- gency medical care, we often provide facilities, variability in venom delivery in mon and most will lose their sensitivity.1 0 adrenaline and immunotherapy even if a sting, and the potential for increasing Conversely, a fluctuating course is their previous reactions have been rela- sensitisation. Thus subjectsDownloaded who rep oforr tpersonal a co usemm only.o n,No wotherith uses so mepermitted peo pwithoutle ex ppermission.erienc- © Medicinetively Todaymild. 2010. life threatening reaction to a previous ing a near lethal reaction followed by no sting but then tolerance of a further sting reaction to a subsequent sting, and then Underlying disease and regular (either deliberate or accidental) from the a near lethal reaction when stung yet m e d i c a t i o n s same insect cannot be reassured that again. We do not fully understand this In some series of sting deaths, subjects they are no longer at risk. Downloaded for personalp huseen only.om Noen otheron, busesut ipermittedt may re withoutlate t opermission.: © Medicinewith uTodaynderl 2009.ying cardiovascular disease • spontaneous variation in reactivity and receiving treatments for this appear Natural history of stinging insect • variability of the amount of venom to be over-represented. The pathophys- a l l e r g y injected with a sting iology of anaphylaxis suggests that it is The often-heard comment that ‘you have • venom allergenicity likely to be aggravated by: had a serious sting and the next sting will • incorrect insect species identification. • pre-existing chronic respiratory Downloaded for personal use only. No other uses permitted without permission. © MedicineillnTodayess o 2008.r cardiovascular disease • treatment with beta blockers and/or agents that inhibit the renin– angiotensin system or have negative inotropic effects on the heart. Beta blockers, in particular, inhibit nat- Downloaded for personal use only. No other uses permitted without permission. © Medicineural syTodaympatho 2007. mimetic activity and the beta effects of adrenaline whether endogenous or exogenous. Alpha blockade may result in treatment with adrenaline having a paradoxically hypotensive effect due to unbalanced beta stimulation. ACE Downloaded for personal use only. No other uses permitted without permission. © MedicineinhibitTodayors m 2006.ay aggravate angioedema, and there is evidence from several studies that the renin–angiotensin system is an important endogenous rescue system in anaphylaxis. Thus, when deciding on medications Figure 6. Level of risk versus population prevalence of sensitisation and sting reaction history. for such patients, the potential major Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2005. 2 0 M e d i c i n eT o d a y ❙ February 2004, Volume 5, Number 2

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Me d i c i n eT o d a y P A T I E N T H A N D O U T

Action plan for patients highly allergic to insect stings

1 . Honey bee sting – flick out any stinger immediately using a Dialling the emergency number is the surest way of getting help fingernail. Even after the stinger comes away from the insect, the quickly, even in remote areas because the ambulance service venom sac contracts and continues to inject venom. co-ordinates all available emergency resources and/or can direct 2 . As soon as there are any local symptoms – i.e. significant pain, you to the nearest emergency care available. Ambulances carry swelling and/or itching around a sting from an insect that adrenaline if for some reason you do not have your EpiPen or if normally causes a life threatening reaction: additional doses are required. • Get help – make sure that someone nearby knows of your If you have any generalised symptoms or need to use Epipen, potential problem. seek medical care immediately. • Find your adrenaline (EpiPen) and get ready to use it. 3 . As soon as there are generalised symptoms – i.e. symptoms General measures beyond the local sting site, such as an all-over rash, itch, – Do not engage in vigorous physical exertion, hot showering or nausea, face swelling or a feeling of impending disaster, or any bathing, or insert the wound in hot water. All of these will of the more severe symptoms listed below, proceed as above increase blood flow and thus absorption of inflammatory p l u s : substances into the circulation. • Dial the emergency number for an ambulance immediately – Application of an ice pack may help to reduce pain and swelling. (000 in Australia). Make sure that the ambulance – Some people advise using a pressure-immobilisation bandage communications officer is told that you have a known for sting allergy. There is no evidence supporting this approach, Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2010. serious sting allergy and are having an allergic reaction. which in some situations can be harmful. Therefore, do not 4 . If you have severe symptoms – i.e. symptoms affecting waste time doing this. swallowing, voice or breathing, or symptoms of light-headedness, – Do not rely on antihistamines or corticosteroids. In most cases impaired vision or threatened collapse, proceed as above plus: these will not help, apart from providing symptomatic relief for • Inject yourself with EpiPen immediately. Do not wait for an minor and local symptoms. Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2009. ambulance to arrive before using your EpiPen. 5 . To use your EpiPen: Care for and renewal of your EpiPen • Remove the device from its container. Keep an EpiPen near you at all times. The EpiPen is stable at any • Remove the grey safety cap. tolerable room temperature, but is best not refrigerated (many • Using a fist-like grip, which allows the barrel of the device to domestic refrigerators freeze intermittently). It should not be stored move freely, push the black nose of the device hard against in the car, where damagingly high temperatures are often reached. Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2008. the front outer thigh. Your EpiPen should be renewed before its expiry date. However, • You will hear and feel the device click, and should leave it in if marginally over the expiry date and the contents are clear and not position for a count of 10 and then remove the device. discoloured (look through the viewing window in the pen), it is likely • The EpiPen can be used through clothes. to be effective still in an allergic emergency. • Take care to minimise the risk of needlestick injury to other persons (e.g. by pushing the exposed needle into a cork), Downloaded for personal use only. No other uses permittedAdapted without from thepermission. action plan © d evMedicineised andToday written 2007. by Dr Simon Brown and used by the and give it to ambulance or medical staff for safe disposal. Royal Hobart Hospital’s Department of Emergency Medicine. benefits on general cardiovascular mor- is an assessment of risk (Figure 6). As stings from insects with limited distribu- bidity need to be carefully balanced risk increases, the thresholds for providing tion (e.g. M. pilosula or the various against the particular riskDownloaded from i n for s e personalc t s euself- inonly.je ctNoa blothere a usesdre permittednaline awithoutnd i m permission. m u n o- © Medicinepaper Todaywasps). 2006. However, subjects need stings in a given individual. therapy reduce. to be warned about potential venom cross-reactivity (e.g. with other M y r m e c i a Ongoing management Avoidance measures ants or wasps, respectively). A key step in deciding an appropriate Relocating to a different geographic area Activities at particularly high risk for course of action for the individual patient may be effective for patients allergic to being stung by insects involve visiting Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2005. 2 2 M e d i c i n eT o d a y ❙ February 2004, Volume 5, Number 2

Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2000. apiaries, pest control activities, failure The efficacy of venom immunotherapy other injectable adrenaline. to wear shoes and accidentally driving appears to be at least 95% for wasp Venom immunotherapy is appropri- into the insects without protection (on and M. pilosula allergies. Efficacy in ate for subjects who have had respiratory a motorcycle or with a car window studies of A. mellifera venom immuno- compromise or hypotension (or symp- open). Wearing shoes and long, light therapy varies from 60 to 100%, but prob- toms suggestive of these) after an insect coloured, clothing and avoiding the use a bly is about 80 to 90%. sting and evidence by in vitro test and/or of perfumes (for honey bees) or accu- Immunotherapy is a major undertak- skin test of specific IgE reactivity to the mulating protein-rich garbage (wasps) ing with its own morbidity. It is intrusive venom. Specialist opinion should be may assist. Care should be taken when of subjects’ time and consuming of sought before initiating immunother- drinking from cans and bottles, which medical resources. In one very large rep- apy, and any underlying cardiorespira- may attract bees and wasps. resentative study of honey bee and wasp tory disorder and its therapies reviewed. venom immunotherapy, 12% of subjects Venom immunotherapy is not appro- A written action plan experienced one or more systemic reac- priate for people with positive skin tests All individuals with a history of immedi- tions during venom immunotherapy.1 2 or RAST results alone in the absence of ate systemic allergic reaction to an insect It is best that such therapy be initiated by any history of immediate systemic allergic sting need a written action plan with those experienced in the procedure. The reaction. It has no proven value in sub- which they and their family and close presence of a significant failure rate jects with local reactions. Unless special associates need to be familiar. Even means that it is prudent that subjects on risk factors are present (e.g. a subject who simple measures such as the contacting immunotherapy continue with their is intellectually challenged, a rural and of another responsible adult and emer- action plan incorporating EpiPen or remote worker, or a subject who has gency care need to be preplanned, and regular reinforcement is neDownloadededed. for personal use only. No other uses permitted without permission. © MedicineToday 2010. The action plan on the use of the Consultant’s comment adrenaline autoinjector EpiPen, given in the box on page 22, has proven accept- The authors of this article are to be congratulated on producing a timely and lucid account able and usable in a large group of of an important problem in Australia. They have made a major contribution to the subject by bringing to our attention the problem with jack jumper ants, and by conducting the first Tasmanian subjects highDownloadedly allerg icfor topersonal use only. No other uses permitted without permission. © MedicineToday 2009. insect stings. EpiPen is widely available, trials of immunotherapy (desensitisation). Insect stings evoke great fear especially in those but patients must understand that this is unfortunate individuals who have had a major reaction to them. only a temporising measure; higher doses There are several very important ‘take-home’ messages in this article: of adrenaline and other measures may be • In Australia we have as big a diversity of stinging insects as that of any overseas required. Subjects at high risk, often those c o u n t r y . • It is sobering to reflect that, despite excellent Australian work characterising the venom with a history of hypotensivDownloadede anaphy lforax ipersonals, use only. No other uses permitted without permission. © MedicineToday 2008. should probably carry two EpiPens or be of the jack jumper ant, and despite intensive lobbying, there is still no support in trained to use adrenaline ampoules for Australia for producing life saving therapeutic preparations of the venom. injection if cost is a problem. • What happens with subsequent stings is unpredictable – there’s no neat evolution to more severe reactions. I m m u n o t h e r a p y • Overall management of patients requires advice to minimise the risk of stings in the future and first aid measures should a sting occur. Venom immunotherapy Downloadedis of pro forv enpersonal use only. No other uses permitted without permission. © MedicineToday 2007. value for A. mellifera (honey bee), wasp • Primary management of anaphylaxis requires adrenaline as soon as possible; in almost and M. pilosula (jack jumper ant) venom all circumstances this should be given by the intramuscular (not the intravenous) route. a l l e r g y . 7 , 1 1 However, M. pilosula and other • Immunotherapy is a serious undertaking, very effective in the right setting, but native M y r m e c i a ant venoms are not gen- appropriate selection of subjects requires many factors to be taken into account, and erally available, with issues of production its prescription should be undertaken only by those with appropriate experience. Professor R.S. Walls and distribution to be overcDownloadedome. Ven forom personals use only. No other uses permitted without permission. © MedicineToday 2006. of A. mellifera, V e s p u l a and P o l i s t e s p a p e r Associate Professor of Medicine wasp are available and subsidised by the University of Sydney, and PBS, but concerns have been expressed Head, Immunology Department that overseas-sourced P o l i s t e s venom may Concord Hospital, Sydney not be appropriate to all local species. Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2005. M e d i c i n eT o d a y ❙ February 2004, Volume 5, Number 2 2 3

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underlying cardiovascular comorbidities), J Aust 1984; 140: 209-211. the prognosis in individuals who have 4 . Douglas R, Weiner J, Abrahamson M, O’Hehir reactions confined to the skin is such that R. Prevalence of severe ant venom allergy in provision of an emergency plan a n d southeastern Australia. J Allergy Clin Immunol 1998; EpiPen may be sufficient. 101: 129-131. Discontinuing immunotherapy is a 5 . Solley GO, Vanderwoude C, Knight GK. risky decision that should be shared with Anaphylaxis due to red imported fire ant sting. a specialist. Limited evidence suggests Med J Aust 2002; 176: 521-523. that most subjects who have tolerated 6 . McGain F, Harrison J, Winkel KD. Wasp sting venom immunotherapy and any inter- mortality in Australia. Med J Aust 2000; 173: 198-200. vening stings can discontinue treatment 7 . Brown SGA, Wiese MD, Blackman KE, Heddle after three to five years with reasonable RJ. Ant venom immunotherapy: a double-blind, prospects, irrespective of skin or blood placebo-controlled, crossover trial. Lancet 2003; 361: test results at the end of therapy. Adverse 1 0 0 1 - 1 0 0 6 . prognostic factors appear to be a history 8 . Brown SGA, Blackman KE, Stenlake V, Heddle of hypotensive anaphylaxis and/or RJ. Insect sting anaphylaxis: prospective evaluation of systemic reactions to venom immuno- treatment with intravenous adrenaline and volume therapy or interim stings while on immu- resuscitation. Emerg Med J. In press 2004. notherapy. Subjects with hypotensive 9 . van der Linden PW, Hack CE, Struyvenberg A, anaphylaxis, in particular, may merit van der Zwan JK. Insect-sting challenge in 324 indefinite immunotherapy. subjects with a previous anaphylactic reaction: current criteria for insect-venom hypersensitivity do Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2010. S u m m a r y not predict the occurrence and the severity of ana- In patients who are allergic to insect phylaxis. J Allergy Clin Immunol 1994; 94: 151-159. stings, sensitisation is very common, clin- 1 0 . Schuberth KC, Lichtenstein LM, Kagey-Sobotka ical reactions are less common and death A, Szklo M, Kwiterovich KA, Valentine MD. Epidemiologic study of insect allergy in children. II. Downloaded for personalo ruse s eonly.ver eNo p othererma usesne npermittedt disab withoutilities permission.are very © MedicineToday 2009. uncommon outcomes. The clinical chal- Effect of accidental stings in allergic children. J Pediatr lenge is to place patients who are allergic 1983; 102: 361-365. to stings in a hierarchy of risk, which has 1 1 . Hunt KJ, Valentine MD, Sobotka AK, Benton a very broad base and a very narrow peak. AW, Amodio FJ, Lichtenstein LM. A controlled trial Management should then be matched to of immunotherapy in insect hypersensitivity. N Engl J Med 1978; 299: 157-161. Downloaded for personalthe use ponly.atie Non tother’s le veusesl opermittedf risk iwithoutn the permission.context © MedicineToday 2008. of a disrupted lifestyle due to fear of a 1 2 . Lockey RF, Turkeltaub PC, Olive ES, Hubbard random, potentially lethal event. A power- JM, Baird-Warren IA, Bukantz SC. The hymenoptera ful management tool for many insect venom study III: safety of venom immunotherapy. stings is venom immunotherapy (hypo- J Allergy Clin Immunol 1990; 86: 775-780. sensitisation), but this is intensive and MT DECLARATION OF INTEREST: None. Downloaded for personaldemanding use only. No other of usesresources. permitted without permission. © MedicineToday 2007. R e f e r e n c e s Studying medicine?

1 . Brown SGA, Franks RW, Baldo BA, Heddle RJ. Or know someone who is? Prevalence, severity, and natural history of jack For our special subscription rates for jumper ant venom allergy in Tasmania. J Allergy Downloaded for personal use only. No other uses permitted without permission. © MedicineTodaymedical 2006. students, contact: Clin Immunol 2003; 111: 187-192. Lisa on (02) 9908 8577 2 . McGain F, Winkel K. Ant sting mortality in or email: Australia. Toxicon 2002; 40: 1095-1100. l i s a a g g e t t @ m e d i c i n e t o d a y . c o m . a u 3 . Harvey P, Sperber S, Kette F, Heddle RJ, Roberts- Thomson PJ. Bee-sting mortality in Australia. Med

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