Managing and Treating Insect Allergy769.56 KB

 Managing Insect Allergies

What is an insect allergy?

Allergies to venoms from stinging insects such as bees, wasps and ants are one of the most common causes of severe allergic reactions (anaphylaxis) in Australia.

Most reactions to insect bites and stings are not severe, however anaphylaxis can occur.

Symptoms of anaphylaxis can include hives all over the body, persistent dizziness (due to a sudden drop in blood pressure), abdominal pain, vomiting, swelling of tongue or throat and difficulty breathing.

Those at greatest risk of anaphylaxis to insects are those who have experienced anaphylaxis following a sting/bite previously, and those with significant heart and lung disease.

Allergic reactions to stinging insects in adults tend to be lifelong.

Adults are at greater risk of anaphylaxis from insect stings than children.

What are the common causes of severe insect allergy?

• Honeybee – is the most common cause of allergic reactions to insects.
• Wasp (Paper wasp and European wasp) – can sting multiple times.
• Jack Jumper Ant (sometimes known as hopper ant) - a medium sized black bull ant mostly found in Tasmania, South Australia, and down the eastern side of Australia.
• Although insects may appear similar, allergy to one type of insect does not usually increase the risk of an allergy to another insect.
• Anaphylaxis to insects is usually due to stinging insects (bees, wasps, Jack Jumper Ants). Anaphylaxis to biting insects (such as mosquitoes, midges and March flies) is very rare.

What to do if you are stung

• Bees usually leave their barbed stinger in the skin and then die
• Flicking the stinger out quickly (not squeezing) may reduce the amount of venom injected.
• Use the edge of your fingernail, a car key or credit card to flick out the stinger.

Remember, most reactions to insect stings/bites are not life threatening.

MILD or MODERATE REACTIONS

Most insect stings and bites cause itch/swelling on the body in the area of the sting/bite. This usually settles within a few days.

Management-

• Cold packs and creams can decrease itch and swelling around the sting/bite
• Oral antihistamines can help decrease itch
• See your doctor if symptoms do not go away within a few days

Note there is less than a 10% chance of developing anaphylaxis with further stings/bites.

Some people develop rash/hives (urticaria) all over their body, without dangerous features of anaphylaxis.

Those with all over rash (even if serious symptoms are absent) should be referred for assessment to a clinical immunology/allergy specialist.

ANAPHYLAXIS

• Signs and symptoms include breathing difficulty, feeling faint, dizzy or passing out (meaning a drop in blood pressure) or severe abdominal pain/vomiting.
• Note abdominal pain/vomiting are signs of anaphylaxis for insect allergy.
• People who are at greatest risk of anaphylaxis are those who have previously had anaphylaxis following a sting.
• Allergic reactions to insects tend to persist, although children are more likely to improve than adults.
• Adults are at greater risk of anaphylaxis to insect stings/bites than children.
• All people who have been diagnosed with anaphylaxis to an insect should be prescribed an adrenaline (epinephrine) injector and have an ASCIA Action Plan for Anaphylaxis completed by their doctor.
• People with a history of anaphylaxis to an insect sting should be referred to a clinical immunology/allergy specialist for possible venom immunotherapy (VIT) to help make them less allergic.

After experiencing anaphylaxis to an insect, you may feel frightened, helpless, or anxious about the possibility of it happening again.

A clinical immunology/allergy specialist will:

• Ask questions to help find the most likely cause of the allergic reaction if unknown. This approach will also help confirm the diagnosis of anaphylaxis.
• Perform tests. Skin prick testing and/or blood testing can help confirm or exclude the diagnosis.
• Prescribe an adrenaline injector if this has not already been done. It is important that anyone who has experienced anaphylaxis to an insect sting/bite always carries at least one adrenaline injector (preferably two) wherever they go.
• Complete an ASCIA Action Plan for Anaphylaxis which must be kept with the adrenaline injector(s) and followed if the person is bitten/stung by an insect.
• Recommend medical identification jewellery should be worn as this will increase the likelihood that adrenaline will be administered in an emergency.
• IMPORTANTLY consider whether insect venom immunotherapy (VIT) should be offered

VENOM IMMUNOTHERAPY (VIT)

What is VIT?

VIT (also known as desensitization) can help to decrease how severe an allergy is over time.  VIT is an effective and successful treatment for severe allergies to bee, wasp, and Jack Jumper ant stings.

Identification of the insect that caused the reaction is critical in selecting the right venom for VIT. VIT is not yet available for treating people with tick allergy.

VIT is a series of injections that introduce very small amounts of insect venom into your body. The amount is slowly increased over time to help your immune system become less allergic to the venom proteins that you are allergic to.

Treatment is via a tiny injection under the skin and consists of 2 phases:

Initiation phase: injections of increasing doses of venom given in hospital by an allergy specialist until the right dose of venom has been reached.

Maintenance phase: regular injections (usually given monthly) of a constant dose, either given in hospital or in general practice by your GP.

Although VIT can provide protection early in treatment, continued maintenance treatment for 3 to 5 years ensures the protection is maximised and long lasting.

It is important that people see their clinical immunologist/allergist regularly during VIT treatment. Stopping treatment too early can result in symptoms of a severe allergic reaction/anaphylaxis returning sooner.

At least one adrenaline injector should be carried during the course of VIT and thereafter unless your doctor advises it is safe to stop.

Government subsidies are available for VIT to bees and wasps on the Pharmaceutical Benefits Scheme (PBS) making it more affordable for people in Australia. There is currently only limited access to Jack Jumper ant VIT in some states.

Who should consider VIT?

Anyone who has a history of anaphylaxis to Jack Jumper ant, bee or wasp stings should seriously consider VIT.

VIT is not helpful in patients with large swelling around the bite or sting site alone. VIT is sometimes considered for adults (not children) who only have a rash/hives all over the body. People should be seen by a clinical immunology/allergy specialist before VIT treatment is considered.

How effective and safe is VIT?

There is a small risk that people having VIT will have anaphylaxis and this is why VIT is done in a medical setting and people stay for a period of observation after the VIT injection. Most people on maintenance VIT can be considered likely to be protected from dangerous reactions to stings whilst maintenance therapy continues. There is still some risk (5 – 20%) of a severe allergic reaction to a sting during maintenance VIT but reactions are usually milder than before treatment. Once a course of VIT is completed there is less than a 10% chance of a severe allergic reaction occurring.

There are risks associated with VIT just as there are risks with not having VIT when you have had a previous anaphylaxis to an insect sting. Discuss the risks with your clinical immunology/allergy specialist.

Strategies to avoid insect bites and stings

• Wear light coloured clothing that covers arms and legs
• Avoid wearing clothes with flowers on them
• Wear shoes when outside
• Avoid perfumes/aftershave or body creams/deodorants which have a smell
• Wear gloves when gardening
• Avoid picking up rubbish which may attract insects
• Be extra careful where there are bodies of water such as lakes/ponds/dams/swimming pools. Chlorinated pools attract bees
• Drive with car/bus/train windows closed
• Keep your drink (cup/glass/bottle/can) indoors or covered. Always check your drinks
  for insects before you sip
• Keep lids on garbage bins
• Keep grass areas mowed (reduce weed such as clover which attracts bees)
• Do not disturb bees, wasps or ants
• Have insect mounds/nests removed by professionals
• Use insect repellents that contain DEET as this may help reduce some bites and stings
• Wear boots and thick clothing such as denim jeans (tuck bottom of jean legs into socks) if in an ant or tick prone area
• Check for ticks after walking in the bush

Ticks should be removed by either using sprays containing ether available from a pharmacy. If the tick does not fall off, you should go to a doctor for removal. Those at risk of anaphylaxis to ticks should have them removed by a doctor in a hospital.

Resources

For further resources and helpful information see

• Australasian Society of Clinical Immunology and Allergy (ASCIA) allergy.org.au/patients/insect-allergy-bites-and-stings (scroll past animations for further links)
• For information specific to tick bite tiara.org.au

Do you know the correct way to remove a tick?

The Australian tick (an arachnid, not an insect) is particularly good at provoking two very serious allergies, Mammalian Meat Allergy and anaphylaxis, so it's essential they're removed correctly. Remember freeze it, don't squeeze it!

Watch the National Allergy Council's short animations for more information and instructions on how to safely remove a tick and how to prevent tick bites.

How to prevent tick bites

Content updated February 2022