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24th May, 202111 min read

Insect bites and stings: Symptoms, causes and treatment

Medical reviewer:Dr Ann Nainan
Author:Dr Lauretta Ihonor
Last reviewed: 22/04/2021
Medically reviewed

All of Healthily's articles undergo medical safety checks to verify that the information is medically safe. View more details in our safety page, or read our editorial policy.

What is an insect bite or sting?

Insect bites – also known as bug bites – are small skin wounds or punctures caused by an insect’s mouth. They aren’t the same as insect stings – these happen when an insect punctures your skin with a special ‘stinger’ on the back of its body and injects a poison (called venom) into your skin.

Most bites and stings aren’t serious, but if you’re allergic to a specific type of bite or sting, they may trigger a life-threatening reaction that needs immediate treatment.

Wasps, bees, ants, mosquitoes and fleas are among the most common biting or stinging insects, but most insects and spiders can bite or sting you.

What do insect bites and stings look like?

If you’ve been bitten or stung by an insect, you may notice a lump on your skin where you were bitten. This lump may be:

  • red
  • swollen
  • itchy
  • painful

In most cases, these symptoms tend to get better within a few hours or days.

But sometimes, a bite or sting causes an allergic reaction, which can lead to more serious symptoms. It’s also possible for a bite to get infected.

Symptoms of an allergic reaction to a insect bite

An allergic reaction to an insect bite can be mild and limited to your skin (large local reaction) or really bad and affect your whole body (generalised allergic reaction).

If you have a mild allergic reaction, you may notice a lot of swelling, redness and pain around the bite or sting. Your skin may also break out in blisters – but this doesn’t happen often.

These symptoms usually get better within 7 to 10 days.

Less commonly, you may have a very serious allergic reaction to a bite or sting. This is known as anaphylaxis or anaphylactic shock, and it can be life-threatening if it isn’t treated immediately.

Anaphylaxis tends to happen within 10 minutes of being bitten or stung and can cause symptoms, including:

  • trouble breathing
  • swelling of your face, mouth, lips, tongue, throat and airways
  • dizziness or feeling faint (or fainting)
  • tummy pain
  • feeling sick (nausea)
  • skin redness
  • a fast heart rate
  • feeling like something very bad is going to happen

Symptoms of an infected insect bite

An insect bite can sometimes get infected, especially if you’ve been scratching it a lot. This is because breaking your skin by scratching or picking at a bite allows bacteria to enter the bite.

If this happens, you may notice that the bite and the skin around it may hurt more, feel tender to touch, look red or have pus in (or coming out of) it.

There’s a risk of an infected bite or sting spreading deeper into your skin – causing a more serious infection, so you should see a doctor as soon as possible if you think a bite or sting has become infected.

When to see a doctor about an insect bite or sting

When to call an ambulance

If you develop any symptoms of anaphylaxis listed above, call an ambulance immediately.

Don’t try to drive yourself (or ask someone else to drive you) to hospital. Paramedics can give you treatment as soon as they get to you in an ambulance, but driving to a hospital will stop you from getting any treatment until you get to hospital.

It’s also important to bear in mind that while anaphylaxis usually happens within a few minutes of being stung or bitten, it can sometimes happen later – so still call an ambulance if you notice any symptoms of anaphylaxis, even if it’s been a few hours or longer since you were bitten or stung.

When to see a doctor

While a severe allergic reaction needs immediate medical treatment, it’s not the only complication of a bite or sting that needs quick medical attention. See a doctor as soon as possible if:

  • your symptoms are getting worse or haven’t started to get better within a few days
  • you were bitten or stung near your eyes or in your throat or mouth
  • the swelling and redness around the bite involves a large area (more than about 10cm) or is spreading
  • the bite or sting, and area around it, is getting more painful, red and swollen
  • there's pus in or around the bite or sting
  • you develop a circular rash around the bite or sting, which looks like a bull’s-eye
  • you have a fever, swollen glands and feel generally unwell
  • you're worried about a bite or sting

Which insects can bite or sting?

Most insects and spiders can bite or sting you. Common biting or stinging insects include:

  • wasps
  • bees
  • hornets
  • ants
  • mosquitoes
  • fleas
  • certain flies, like horseflies, sand flies, deer flies, black flies and stable flies
  • ticks
  • bedbugs
  • midges

And while many insects and spiders can bite or sting, the most serious stings are caused by certain:

  • wasps – yellow jackets and paper wasps
  • bees – honey and bumble bees
  • hornets – yellow and white-faced hornets
  • ants – fire, bulldog, harvester and jack jumper ants

How to tell if you’ve been stung or bitten

Your symptoms will usually help you tell if you’ve been bitten or stung by an insect. If you see a doctor, they’ll usually confirm an insect bite or sting by looking at the affected part of your skin, and asking you about your symptoms and what you were doing before your symptoms began.

It’s not always easy to tell if you’ve been bitten or if you’ve been stung, but if you’ve been stung, you may see a stinger attached to your skin. And if you’ve been bitten by a tick, it will often remain stuck to your skin.

Read more about how to identify different types of insect bites (including images to help you identify the bites). Discover too what flea bites look like and how you can treat them.

What is the treatment for an insect bite or sting?

If you’ve been bitten or stung by an insect and you aren’t having a serious allergic reaction (anaphylaxis), you can usually take care of this yourself by following the steps below.

  1. Scrape off the insect’s stinger if it's still in your skin – use the edge of a knife, fingernail or something similar, and do so as quickly as you can. Avoid pulling out the stinger as this may squeeze more of the poison (venom) into your skin.
  2. Wash the bite or sting with soap and water.
  3. Place a cold compress on the bite or sting for at least 10 minutes – use an ice pack or a cloth cooled with cold water.
  4. Avoid scratching the bite or sting – this will help reduce your risk of infection.
  5. Keep the affected area raised (if possible) – this can help reduce swelling.
  6. Take painkillers and antihistamines, or use special creams for bites if you have a lot of (or ongoing) pain, swelling and itching – speak to a pharmacist for advice on how to get and safely use these medicines.

Remember to call an ambulance if you’re having a serious allergic reaction. You should also see a doctor as soon as possible if you have any of the symptoms of infection or a mild allergic reaction. See the ‘When to see a doctor about an insect bite or sting’ section above for the symptoms you should look out for.

How to treat an infected insect bite or sting

If an insect bite or sting gets infected, you will usually need antibiotics to treat the infection. You should take them as directed by a doctor and finish the course, even if you feel better.

How to treat a tick bite

Ticks often stay stuck to the skin when they bite. If you’ve been bitten by a tick and this happens, you should use tweezers to gently remove it from your skin – make sure you grip the tick as close to your skin as possible and pull upward to remove it.

Most tick bites are harmless, but it’s important to save the tick and show it to a doctor if you develop symptoms – including a fever, large circle-shaped red rash or flu-like symptoms – within the next few weeks. This is because a specific type of tick can spread Lyme disease – an infection that needs medical treatment. You can save a tick that’s bitten you by sealing it in a piece of see-through sticky tape.

If you can’t easily remove the tick with tweezers, don’t try and force it. See a doctor instead. You should also see a doctor if you think the tick has been stuck to you for more than 36 hours.

How to prevent insect bites and stings

You can reduce your chances of being stung or bitten by a insect by:

  • covering as much of your skin as possible when outside – wear shoes, long trousers and long-sleeved tops
  • using insect repellent that contains 50% DEET (diethyltoluamide) and reapplying often – as advised on the repellent’s packaging
  • wearing gloves when gardening
  • not spending time around stagnant water, flowering plants, rubbish, compost and other sources of odours and scents that can attract insects
  • not wearing strong perfumes and scents
  • keeping uneaten food covered when you’re outside
  • keeping as still as possible and moving away slowly if you come across bees, wasps, hornets or other stinging insects – never try to remove bee or wasp nests yourself, call a professional instead
  • taking extra precautions if you’re travelling to a part of the world where there’s a risk of serious infection caused by insect bites or stings (e.g. malaria and dengue)

What can I expect after getting an insect bite or sting?

Most insect bites and stings aren't serious and usually get better within a few hours or days. But if you have a serious allergic reaction or an infection, you’ll need to see a doctor or go to hospital for treatment, and it may take longer for you to recover.

It’s important to always pay attention to your symptoms after every insect sting or bite. This is because people don’t have allergic reactions the first time they’re stung or bitten by a specific type of insect. It takes several stings or bites by that insect to trigger your immune system in a way that causes an allergic reaction.

And if you’ve had a serious allergic reaction to a sting or bite, it’s not clear how you may respond to another one in the future – some people have no reaction the next time they’re stung or bitten, while others have a milder reaction.

If you had an anaphylactic reaction to a bite or sting and a doctor gave you an emergency injection (often a pen or syringe of adrenaline) to use if you have a future anaphylactic reaction, carry this pen or injection with you at all times.

Your questions answered

Should I pop a bug bite blister?

“No, don't pop the blister as your skin may get infected. Instead, cover the blister with a bandage or plaster to protect it. If the bite gets red and sore, swells up, or pus builds up in it, it may be infected and you should see a doctor.” – Answered by Dr Rhianna McClymont, Lead Doctor at Livi. Click here to speak to a registered doctor by video, today (UK only).

Are there any skin conditions that look like bug bites?

Bug bites can cause red, swollen, itchy or painful skin lumps to appear on your body. And if you’ve had a mild allergic reaction to an insect bite, you may also develop a larger patch of red, swollen and painful skin around the bite. These skin changes may look like other skin conditions, including a skin infection, a plant sting, a skin injury, contact dermatitis, chickenpox and hives (urticaria). It can be hard to tell the exact cause of a change in your skin, so see a doctor if you have any unexpected or unusual skin changes.

Do bed bug bites turn into blisters?

Bed bug bites usually look like clusters of red, itchy welts in a line or zigzag pattern. They don’t typically blister, but if they do, you should see a doctor for treatment as soon as possible.

Key points

  • insect bites are small skin wounds or punctures caused by an insect’s mouth
  • insect stings are small skin punctures made by a special ‘stinger’ on the back of an insect’s body – if you’re stung, the insect injects a poison (called venom) into your skin
  • most insect bites and stings aren’t serious and get better within hours or days
  • it’s possible to have a life-threatening reaction (called anaphylaxis) to a bite or sting if you’re allergic to it
  • call an ambulance if you develop symptoms of a severe allergic reaction, including trouble breathing; a swollen face, mouth or throat; dizziness and fainting
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