Insect Bites and Stings - Causes, Symptoms & Treatment

Insect bites and stings are usually not serious and get better within a few hours or days. 

When an insect bites, it will release saliva that can cause the skin around your bite to become red, swollen and itchy. 

Insect bite symptoms are usually minor, however, some insect bites can become infected or cause an allergic reaction (anaphylaxis). 

If you do find yourself bitten, it is rarely something to worry about! There are insect bite treatments available and many ways you can soothe the bites. 

Symptoms 

Most insect bites and stings cause nothing more than minor discomfort or itching, but some can be more serious. The severity of a bite or sting will depend on the insect and the person’s sensitivity.

Typical symptoms of insect bites and stings include:

  • Small, puffy bumps that appear on the skin after you have been bitten. The bumps might become red, hard, swollen and itchy. Sometimes you will have multiple bites in the same area. 
  • Swollen spots that develop blistering on top. 
  • Burning and itching sensations.
  • Painful and itchy rashes that are caused by an inflammatory reaction at the site of the bite.
  • Pus-filled blister-like sores.

You should monitor and keep an eye on your bites. Many bites will clear up within a few hours and symptoms typically ease. On the other hand, sometimes bites and stings can cause complications. 

Allergic reactions to insect bites

Severe allergic reactions or anaphylactic shock is not very common. However, when one occurs they become a medical emergency. An allergic reaction can potentially be life-threatening and if it's not treated quickly, it can be fatal.

Lyme disease 

Lyme disease is a bacterial infection spread to humans by infected ticks. A round-shaped rash around a bite is an early symptom of Lyme disease. The rash usually appears within the first month of being bitten, however, it can appear up to three months after. 

Some people will experience flu-like symptoms in the days and weeks after being bitten. 

A small number of those who are diagnosed with Lyme disease continue to have symptoms that can last for years. They are often compared to fibromyalgia and chronic fatigue symptoms.

Malaria 

Malaria is an infection carried by mosquitoes. It is common in tropical and subtropical countries. If you are travelling to a country where malaria is a high-risk, you might be offered a type of medicine known as an antimalarial.

The symptoms of malaria usually begin a couple of weeks after getting bitten by an infected mosquito.

The most common symptoms of malaria include a high temperature, headaches, sweat and chills and vomiting and diarrhoea.

Causes

Insects that bite in the UK include:

  • Midges
  • Mosquitoes
  • Fleas
  • Bedbugs
  • Spiders
  • Mites
  • Ticks

Insects that sting in the UK include:

  • Bees
  • Wasps 
  • Hornets

Some people are more prone to being bitten or stung by insects. This is down to a few different reasons. 

Body odour

Insects are attracted to certain compounds that are found on human skin and in your sweat. Genetics and certain bacteria on the skin can make you more attractive to certain insects. 

Skin bacteria also plays a part in body odour. People with a low diversity of microbes are more likely to attract insects.

Alcohol 

A study has found that people who have consumed more alcohol are more attractive to insects such as mosquitos. 

Pregnancy

Pregnant women have a high body temperature and exhale more carbon dioxide, which makes them more attractive to certain types of insects. 

Diagnosis 

Checking whether you have a lump or sting

You usually don’t need to see a GP if you have been bitten or stung. You can check yourself, as normally a bite or sting will leave a small, swollen lump on the skin. The lump may look red, even if you can’t see it you should be able to feel it. 

An insect will bite you by making a hole in the skin to feed. Most insects that sting will do it as a defence by injecting venom into your skin. 

When to call 111/an emergency doctor

  • If your bite is extremely swollen or blistered.
  • If there is pus, which indicates an infection. 

When to call 999

  • Wheezing or difficulty breathing. 
  • Nausea, vomiting or diarrhoea.
  • Fast heart rate.
  • Dizziness or feeling faint. 
  • Trouble swallowing (dysphagia).
  • Confusion, anxiety or agitation.

Treatment 

You can often treat an insect bite or sting yourself without having to seek medical advice. 

Removing the sting or insect

If anything is left on your skin after being bitten or stung, the first thing you need to do is carefully remove it.

Bee, wasp or hornet stinger

To remove a bee, wasp or hornet stinger you should scrape it sideways with your fingernail. Do not use tweezers to pull it out as you could squeeze and spread venom out. Once it has been removed, wash the area with soap and water. 

Tick

To remove a tick you should use tweezers or a tick removal tool. Grasp the tick as close to the skin as possible and slowly pull upwards. 

Be careful not to leave any of its mouth in your skin. Once you have removed the tick, dispose of it. Clean the bite area with soap and water or an antiseptic. 

Caterpillar

To remove a caterpillar, use a tweezer being careful not to disturb it. If you disturb the caterpillar it will release more hairs. 

Remove any jewellery in case your skin becomes swollen. Take your clothes off and wash them at a high temperature. 

Apply ice

If there is swelling at the site of your bite or sting you can apply an ice pack or a cold compress to reduce it.

Raising the affected area above the level of your heart will also reduce swelling. 

Take painkillers

If you experience pain from the sting or bite, take painkillers such as ibuprofen or paracetamol.

Antihistamines

Antihistamines can be used to relieve any itching. Do not take antihistamines if you have had caterpillar hairs on your skin.

Hydrocortisone cream

You can apply hydrocortisone cream, which is a topical anti-inflammatory cream to your bite or sting. This will help to reduce itching and swelling. 

Even though insect bites can be annoyingly itchy, try your best not to scratch the affected area. Scratching your bites can lead to an infection.

Prevention

Use insect repellent

To protect against insects, it is recommended to use an insect repellent that contains 20 to 30 percent DEET. You should apply the repellent to any exposed skin and your clothes. If you are wearing sun cream, make sure this is completely dry before applying the insect repellent. 

Wear appropriate clothing

Make sure you dress appropriately to prevent bug bites. If you know you are going to be in wooded areas, or out at night, cover as much skin as possible. Opt for long-sleeved shirts, full-length pants and closed-toe shoes. 

You can also pre-treat outer layers of clothing with insect repellent if it contains permethrin. Be sure to let the clothes dry for a minimum of two hours before you wear them.

Use bed nets 

If you’re camping or sleeping outdoors, use bed nets to prevent insects from biting you during the night. If possible, use a bed net that has been pre-treated with a pyrethroid insecticide. 

Check for outbreaks

You can keep your eye on the CDC Travel Health Notices website. This will warn you of any outbreaks in the area you are travelling to. 

Don’t panic

If you encounter an animal that is known to sting, such as wasps, bees and hornets, then stay calm. Back away from the insect slowly. Don’t swat around at them or make any sudden movements as this can alarm them and provoke them to sting. 

Olivia Malone - Medical Content Writer
James O'Loan - CEO & Superintendent Pharmacist
James O'Loan , CEO & Superintendent Pharmacist on 18 July 2023
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