Bee & Wasp Stings

Bees and wasps are the commonest cause of insect allergy in the UK. They are closely related to each other and look similar.  It’s the venom (poison) in their stings that causes allergy.  Not everybody who gets stung develops an allergic reaction and stings can affect people in a number of ways. 

An allergic reaction to venom can cause a number of symptoms including

  • flushing of the skin
  • itch
  • swelling
  • nettle rash (hives)
  • stomach cramps
  • sickness
  • difficulty in breathing
  • feeling faint
  • blacking out

 

These symptoms will develop within 60 minutes of the sting and usually quicker than that. They may be mild and just affect the skin.  More worryingly they can affect your breathing and make you faint or feel faint.  This is called anaphylaxis and can be life threatening.
 
Other reactions can occur with stings.  These may be uncomfortable but are usually not life threatening

  • Most stings from bees and wasps just cause pain, redness and swelling that last for a few hours.
  • Some people will react much more than normal around the sting.  This causes a large, red bump which develops over 2 days or so. It may be very big and can be painful as the skin stretches. Anyone concerned that this has happened should see their family doctor for advice.
  • Anybody unlucky enough to get stung very many times all at once can be poisoned by the venom.  The symptoms can be very similar to an allergic reaction and emergency treatment may be needed. Being stung many times all at once usually occurs when the insects or their nest is under attack.

Who gets allergy to insect stings?

Anybody who is stung may become allergic to bee or wasp venom. The people most at risk are those with outdoor jobs like farmers, gardeners and grounds-men.  Bee keepers have regular contact with honey bees and it is not unusual for them to become allergic.  Wasps can build their nests in roof spaces so builders and roofers are at risk.  Men are more likely to develop bee or wasp allergy but that is probably because they do more outdoor jobs than women.  

How does allergy to insect stings develop?

Allergy is due to your immune system reacting to something it should normally ignore.  With bee and wasp allergy you react to chemicals within the insects’ venom. 
First of all your immune system has to learn to recognise the venom.  This will happen with an earlier sting and nearly everybody with bee or wasp allergy can remember a sting (or more than one sting) that didn’t cause a problem.
At the time of this first sting your immune system will produce immunoglobulin E (IgE) which can recognise the venom. This sticks to special cells around the body called mast cells. These contain the potent chemicals that cause an allergic reaction.
An allergic reaction will occur if another sting occurs and the IgE recognises the venom. When the venom sticks to the IgE it triggers a chain reaction that finally makes mast cells release their contents. How bad a reaction is depends on how many of the body’s mast cells release the potent chemicals that cause allergic symptoms.
 

What happens during an allergic reaction to insect stings?

During an allergic reaction potent chemicals are released around the body.  The most important chemical called histamine.  Histamine has a number of effects around the body:

  • Flushing 
  • Itch –this can happen at just one place or all over the body
  • Sneezing and a runny nose
  • Difficult in breathing.  
  • Stomach cramps, sickness and diarrhoea
  • Feeling faint
  • Blacking out

With bee and wasp allergy the sting introduces the venom directly into the blood stream. The allergic reaction occurs within the blood vessels and this can have dramatic effects on the blood circulation and the heart.  People with allergic reactions to insect venom often feel faint or blackout as a consequence.  This may happen very quickly – even within a minute of the sting.

Can bee and wasp allergy be life-threatening?

In the UK about 5 people per year die of allergic reactions due to bee and wasp allergy. Many, many more people get stung and most of these have no problems with allergy.

What happens if I am stung again?

If you have an allergic reaction to a sting there is a high risk that you will react if you are stung again. Reactions do not always get worse with each new sting; some people who have had a bad reaction may have a much smaller reaction the next time they are stung.

As time goes by the chance of reacting gets smaller.   After 10 years of not being stung your chance of having a reaction is about the same as somebody who has never had a problem.

How is bee and wasp allergy diagnosed?

Anybody who has had a severe allergic reaction after a sting should be seen by a doctor specialising in allergy. To make the diagnosis of allergy he/she will ask about what happened to you.  This will help the doctor decide if you have had an allergic reaction and whether it was a bee or wasp that was the cause. 

Tests will then be done to show whether it was allergy to bee or wasp that was the problem.  The tests can either be skin prick tests or allergy blood tests.  Often both skin and blood tests are done. Because it is sometimes difficult to tell wasps and bees apart most doctors will test for both both bee and wasp venom allergy together.  Blood and skin prick tests for venom allergy should always be delayed until 6 weeks after the sting as before this they are not always accurate.

What can I do in future to avoid problems?

1. Don’t get stung!

If you have had an allergic problem with an insect sting it is essential to try and avoid further stings. There are certain things you can do to reduce the risk of a getting stung again

  • Don’t walk barefoot outdoors.  Bees feed on clover which grows within grass and lawns and wasp nests can be in the ground.
  • Avoid wearing bright colours. Bees are drawn to bright colours in flowers and will mistake your clothes for a source of food
  • Avoid strong scents. Scented products such as perfumes, shampoos and sun creams will attract bees
  • Don’t leave foods  - especially sweet ones  - exposed.  Wasps have a sweet tooth and will be drawn towards them. A can of drink can be dangerous – the wasp is drawn to the sweet fluid and will crawl inside.  It then gets stuck inside and when you take a drink you get a mouthful of angry wet wasp.
  • Wear thick gloves when working in the garden.  Wasps may have their nest at ground level and get caught within dead leaves.  Also wear trousers and long sleeved shirts to cover as much skin as possible. In the autumn they are drawn to fallen fruit and these should be handled with caution.
  • Be careful about rubbish and litterbins.  They are a source of food for wasps who will scavenge from them.  Keep your own bin wasp-free by ensuring that the lid is kept firmly closed at times. If bottles are kept for recycling make sure they are washed thoroughly before being left out.
  • If a bee or wasp comes too close try not to panic.  Keep still- if you wave your arms around too much the insect will think it is under attack.  It will then fight back and call on insects from the same nest to come and join the fight!

 

Hover flies look just like wasps.  This is to protect them from predators. They don’t sting and they are not a problem for people with wasp allergy.  It’s worth being able to tell the 2 apart – that way if a hover fly gatecrashes your picnic you won’t have to panic.

wasphornet

2. Be prepared

If you have had an allergic reaction to bee or wasp venom you need to be prepared for what you are going to do if you get stung again. You may get stung somewhere remote or when you are by yourself and so it is important to think about what you are going to do.  Your doctor will normally prescribe some medication to use if you are stung again.  It is important that you carry this around with you all them time. You can never be sure when you might get stung; central heating allows bees and wasps to survive even in winter.

If you have had a bad reaction your doctor should have prescribed you an adrenaline pen to use if you have another sting.  This drug reverses the effects on an allergic reaction and can be life saving.  It has to be given injected into a muscle and the adrenaline comes in a ‘pen’ with a spring loaded needle.  This might look a bit scary first time but it’s important to remember that using adrenaline quickly may save your life if you have an allergic reaction.  Learning how and when to use the adrenaline pen is important and your doctor should show you.

Your doctor may also prescribe you antihistamines (either as a tablet or a liquid) to take if you have a less severe reaction. 

If you have a reaction to a sting you should get medical help as soon as possible.  This will usually mean going to hospital for further treatment.

3. Have desensitisation treatment

Your immune system can be taught not to react to stings.  This should stop you having severe allergic reactions in the future.  The treatment is called desensitisation or immunotherapy.  This treatment is only given in hospital in specialist allergy clinics. It is given to people who have had severe reactions (difficulty in breathing, feeling faint or blacking out) to bee or wasp venom. It doesn’t work for people who react with lots of swelling around the sting but don’t have more severe symptoms.

The whole treatment course goes on for 3 years.  During the first 12 weeks you have an injection a week and for the rest of the time one injection every 4-6 weeks.  The injection contains bee or wasp venom; you get a course of treatment for whichever caused a reaction. 

At the beginning of the treatment the injections contain tiny amounts of venom; each week the dose gets a little bigger.  By the 12th injection the amount of venom in the injection is about the same as in a single sting. Once you have reached this top dose of venom you start to be protected against further stings.  Every injection after this is the same strength and helps to ensure that the protection is continued. 

The injections contain something to which are allergic and reactions can occur after them. These normally happen within the first hour after the injection.  Because this is a risk you will be asked to stay in clinic until the danger period is over. During this time you will be looked after by trained staff; they will monitor you carefully and quickly start treatment if you have an allergic reaction. Though these reactions can occur any time during the treatment course they mostly occur during the time when the dose of venom is being increased. Fortunately these reactions to treatment are rare.

Immunotherapy is very effective and will protect against having a severe reaction in the future.  Wasp immunotherapy is more successful than bee; nobody knows why. Desensitisation doesn’t seem to have any long lasting side effects and most people receive their treatment without any problems.

Can I react to insects other than bees and wasps?

Hornets are very closely related to wasps and may cause allergic problems too.