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Insect bites and stings

Key points

  • In the UK, a bite or sting from an insect, such as flies, fleas, bees and wasps, usually causes a mild irritation.
  • Symptoms of a bite include an itchy raised spot, and a sting usually causes a burning sensation.
  • Some bites and stings can cause a serious allergic reaction called anaphylaxis, which requires urgent medical treatment.
  • Bites and stings from insects abroad are more serious, for example mosquitoes that spread malaria.

Featured FAQ

Can I use diethyltoluamide (DEET) on my child? If so, how often should it be applied?

Insect repellent products containing DEET are the most effective at preventing mosquito bites. DEET is available in a range of formulations including sprays, lotions and as a roll-on. It can be used safely on the skin of children who are over the age of two months.

See all FAQs about insect bites and stings

In the UK, being bitten or stung by an insect usually causes no more than a small irritation. However, for some people, being bitten or stung can lead to serious allergic reactions, so it's important to know what to do if this happens.

In countries affected by diseases that are spread by insects, avoiding being bitten is one of the most important ways of preventing serious insect borne illnesses.

About bites and stings

In the UK there are a variety of biting and stinging insects, some of which are listed below.

  • Common biting insects include flies, fleas, midges, mites and mosquitoes.
  • Common stinging insects include bumblebees, honeybees, hornets and wasps.

When an insect bites you, it makes a tiny hole in your skin so that it can reach your blood to feed on it. When you get stung, the insect punctures your skin and injects venom. As well as causing redness, pain and swelling to the area, this venom can cause a more severe allergic reaction in some people.

Symptoms of bites and stings

In most people, an insect bite will form a red, itchy spot or lump. These usually clear up within a few days and don’t need any treatment. Insect stings usually cause an intense burning pain and redness that generally clears up in four to six hours.

Sometimes a bite or sting can lead to complications such as an allergic reaction or infection. In a few people, stings will cause a dangerous allergic reaction called anaphylaxis.

Complications of bites and stings

Infection

Insect bites and stings can become infected with bacteria. Instead of clearing up after a few days, the area around it becomes more red and sore, and pus may build up inside. Infected bites or stings may make you feel unwell with flu-like symptoms and swollen glands.

You may also notice a red line coming from the bite and going towards your armpit or groin. This is caused by inflammation in your lymphatic channels. The lymphatic system is made up of the tissues and organs, including the bone marrow, spleen, thymus and lymph nodes. They produce and store cells to fight infection and disease. The channels that carry lymph may become red and inflamed.

Allergic reaction

If you’re allergic to an insect’s saliva (for a bite) or the venom (for a sting) you may have a more serious reaction. The allergic reaction is usually around the area of the bite or sting, which may become more itchy or swollen. This is called a local reaction and usually clears up within a week.

Your immune system protects you from harmful substances that may enter your body, such as bacteria and viruses. Sometimes your immune system mistakenly recognises something harmless as harmful and reacts to it – this is an allergic reaction. The substance responsible for causing the reaction is called an allergen. For example, if you're allergic to bee stings, the allergen will be the venom from the sting.

To get an allergic reaction, your body needs to have been exposed to an allergen before. This is called sensitisation.

Anaphylaxis

Some people develop a severe, whole-body allergic reaction to bites or stings – most commonly bee or wasp stings – called anaphylaxis, or anaphylactic shock. This is a rare but potentially fatal condition.

Symptoms of anaphylaxis can include:

  • itching and swelling all over the body
  • blocked or runny nose
  • swelling of the airways, throat and tongue, making you wheezy at first and then making it difficult to breathe
  • dizziness, light headedness, fainting and collapse
  • rapid pulse
  • sickness, vomiting and abdominal (tummy) pains

Anaphylaxis can lead to the person losing consciousness if he or she doesn’t get immediate medical treatment.

If you have had a serious allergic reaction before, your GP may prescribe a dose of adrenaline to carry with you. Adrenaline is a hormone (a chemical that occurs naturally in your body) that relaxes your airways, and improves circulation. It therefore helps to reduce any swelling and make breathing easier.

Single doses of adrenaline are available in the form of an auto-injector pen – an injection that you give yourself. This consists of a sterile syringe containing adrenaline that is ready to be used in an emergency. Adrenaline should be given as soon as possible if symptoms of anaphylaxis develop. You should always seek emergency medical help immediately after taking adrenaline – even if your symptoms appear to be improving.

As another precaution, it’s wise to wear a medical identification bracelet or tag. This gives details of your allergy and a telephone number that anyone can call for more information in case you develop anaphylaxis.

Treatment for bites and stings

You need urgent medical attention if you:

  •  have signs of having a severe allergic reaction (anaphylaxis)
  • have been stung by several insects at the same time and are feeling unwell (eg abdominal pain, vomiting, blocked or runny nose)
     

Self-help

Insect bites can be painful or itchy, but try not to scratch them as this can make the symptoms worse. Wash the affected area with soap and water and pat your skin dry.

You can relieve the pain and swelling by applying a cold compress (a cloth soaked in iced water).

Stings are typically painful and cause swelling of the skin, but aren't usually dangerous unless you're severely allergic to the venom. If you can see the sting, remove it as soon as possible. You can scrape it out with a fingernail or a credit card. Don't try to grab the sting between your fingers or with tweezers. This can cause the venom sac to squeeze its contents into your skin.

Medicines

A cream or ointment containing crotamiton or hydrocortisone can help reduce itching. You can buy low-dose hydrocortisone cream over the counter but don't use it on broken or infected skin or for more than a week. Over-the-counter painkillers such as paracetamol can relieve some of the discomfort.

If the lump spreads beyond the original site, or itchiness is troublesome, antihistamine tablets can relieve the symptoms. Some antihistamines (such as chlorphenamine) may cause drowsiness. This can be an advantage at night when the itchiness might disturb your sleep. However, it can be dangerous if you need to drive or operate machinery. For this reason it’s often better to ask your pharmacist for a non-sedating antihistamine such as loratadine or cetirizine.

If you have an infected bite or sting, your GP may prescribe a course of antibiotics to take by mouth.

Always ask your GP or pharmacist for advice and read the patient information leaflet that comes with your medicine.

Tick bites

Ticks are tiny spider-like creatures that attach to your skin by their mouth and feed on blood. They usually feed on animals such as sheep and horses. Most often, people are bitten by ticks they have picked up when walking through long grass.

If you find a tick attached to your skin, remove it as soon as possible. Use tweezers, grasping as close as possible to the skin so you don't leave the head or mouth parts behind. Don’t try to dislodge the tick by using petroleum jelly, alcohol or a lit match, as these methods don’t work and may cause the tick to release more fluids.

In some areas, particularly where there are wild deer, ticks may carry bacteria called Borrelia burgdorferi that can cause a condition called Lyme disease. Infection from a tick is usually only passed on after it has been in your skin for more than 36 to 48 hours. If you develop flu-like symptoms or a circular rash within a few weeks of a tick bite, it's important that you see your GP. Lyme disease can be treated with antibiotics but if left untreated, it can cause more serious symptoms affecting the nervous system, joints and heart.

Prevention of bites and stings

You can reduce your risk of insect bites and stings by:

  • wearing insect repellent
  • sleeping under a suitable net if mosquitoes are a problem at night
  • wearing long sleeves and trousers if you’re outside in the evening, especially near water – tucking trousers into socks or boots, and shirts into trousers will also help
  • keeping picnic foods covered up as much as possible – sweet foods and drinks attract insects
     

Bites and stings abroad

In the UK, the threat to health from insect bites and stings is relatively low. This isn't always the case abroad, and it's important to be aware of the possible risks if you’re travelling to other countries. Your GP can give you up-to-date advice about appropriate preventive treatments, such as anti malarial tablets.

In tropical countries, malaria is one of the most important issues to consider. In malarial areas, take care not to get bitten by using an insect repellent containing the chemical diethyltoluamide (DEET). You should also cover up at times when mosquitoes are most active (usually dusk and dawn). Sleeping under a mosquito net is another important way of preventing bites.

You should still take these precautions even if you’re taking anti malarial medicines because in tropical countries the insects may carry other diseases too. Anti malarial medicines greatly reduce your risk of malaria, but there’s no guarantee that they will be 100 percent effective.

 

Reviewed by Natalie Heaton, Bupa Health Information Team, August 2013.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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