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Dr. Chrysoula I. Liakou MD, PhD
- Treated online: Yes. Infected bites without fast-spreading redness or a high temperature are assessed and treated by video.
- Reaction or infection? redness, swelling and itching that start within hours of a bite are a reaction, not an infection, and most bites never need antibiotics.
- Signs of infection: a bite that becomes hotter, more swollen and more painful over the following days, or leaks pus.
- Treatment: antibiotic tablets, usually for 5 to 7 days, when a bite is infected; an antibiotic cream can treat a small crusted area.
- Emergency: call 112 for spreading redness with a very high temperature, a fast heartbeat or breathing, confusion, or cold, clammy or pale skin.
Do not book a video appointment if an infected bite comes with a very high temperature, a fast heartbeat or fast breathing, purple patches on the skin, dizziness or fainting, confusion, or cold, clammy or pale skin. Call 112 or go to an emergency department, and do not drive yourself. Severe pain that seems far worse than the bite looks also needs urgent in-person care.
Can an online doctor treat an infected insect bite?
Yes. A doctor can see on camera whether a bite is infected or simply inflamed, which is the key question, because most red, swollen bites are a reaction that does not need antibiotics. When a bite is infected, the doctor can prescribe antibiotics and follow it up. Infection that spreads fast, or comes with a high temperature and feeling very unwell, needs urgent in-person care.
How an online consultation helps with an infected bite
- Reaction or infection?: The timing and the look of the redness tell a normal reaction from an infection, so you get antibiotics only when they help.
- The right antibiotic: Chosen after the doctor checks allergies, pregnancy and the medicines you take.
- The spread checked: How far the redness reaches and whether you feel unwell decide whether you need in-person care.
- A follow-up plan: What should improve within 2 to 3 days of starting antibiotics, and what to do if it does not.
What the doctor checks in an online infected bite consultation
The doctor checks how unwell you are first, then looks closely at the bite. The doctor asks about:
- Warning signs: a high temperature, chills, a fast heartbeat, dizziness or confusion.
- The bite: when you were bitten, by what if you know, when the redness started and how it has changed.
- Signs of infection: warmth, increasing pain, pus, crusts, red streaks or swollen glands.
- Where it is: bites on the face, near the eye, or on the hands and feet need more care.
- Your health: diabetes, a weakened immune system, swelling of the legs, past skin infections, allergies to antibiotics, pregnancy and the medicines you take.
Before the call, draw around the edge of the redness with a pen and note the time, so you and the doctor can see whether it is spreading.
How do you know if an insect bite is infected?
Timing is the best clue. A reaction starts soon after the bite, usually within hours. An infection takes longer to develop, and it gets worse, not better:
Swipe sideways to compare →
| What differs | Normal reaction | Large local reaction | Infected bite |
|---|---|---|---|
| When it starts | Soon after the bite | Within hours, growing for 1 to 2 days | Later, often after a day or more |
| Main symptom | Itching | Swelling and itching | Pain and heat |
| How it changes | Settles; redness and itching can last up to 10 days | Swelling peaks, then settles | Gets hotter, more swollen and more painful |
| Other signs | None | None | Pus, crusts, swollen glands, a high temperature |
| Antibiotics? | No | No: an antihistamine, sometimes steroid tablets | Yes, after a consultation |
Redness can be harder to see on brown and black skin, so feel for warmth and swelling and compare with the skin around the bite.
Infected mosquito, gnat and other bites
The signs of infection are the same whichever insect bit you: the skin around the bite feels hot, looks red or darker, hurts and swells, and pus or fluid may come out of it. What differs is how the bite looked before it became infected:
Swipe sideways to compare →
| Bite or sting | What it looks like at first | Infection |
|---|---|---|
| Mosquito | Small, raised and itchy | Possible, usually after scratching |
| Midge or gnat | Small and raised, in groups | Possible, usually after scratching |
| Flea | In groups, usually below the knees | Possible, usually after scratching |
| Mite | Very itchy lumps, sometimes with blisters | Possible, especially when blisters are scratched |
| Horsefly | Large and painful, and may bleed | Often becomes infected |
| Bee, wasp or hornet | A small mark where the sting went in, with pain and swelling | Possible, especially after scratching |
A bite that leaks fluid or pus and is also hot, red, painful and swelling should be checked. A bite that is only itchy and slowly fading is healing, even if it looks dramatic.
Why do insect bites get infected?
Bacteria on the skin get in through the small break left by a bite, and scratching makes the break bigger. Infection can stay on the surface or spread into the deeper layers of the skin:
- Impetigo: sores that burst and leave crusty, golden-brown patches, often where a bite has been scratched.
- Cellulitis: painful, hot, swollen skin that spreads, sometimes with blisters, swollen glands and feeling unwell.
- An abscess: a painful lump filled with pus, which may need draining.
Some bites become infected more often than others: horsefly bites are large and painful, may bleed, and often become infected. Infection is also more likely with poor circulation, diabetes or a weakened immune system, swelling of the legs from lymphoedema, or a past skin infection.
Which infected bite treatment might the doctor recommend?
The first decision is whether the bite is infected at all. This is the framework the doctors use, in line with NICE and NHS guidance:
Swipe sideways to compare →
| What you have | Likely first step | Suitable for online care? | When in-person care is needed |
|---|---|---|---|
| A red, itchy bump within hours of a bite | A cold compress and an antihistamine | Yes | Not needed |
| Large swelling that grew over a day or two, itchy but not very painful | An antihistamine, sometimes steroid tablets | Yes | If the face, mouth or throat swells |
| A bite getting hotter, more swollen and more painful after a few days | Antibiotic tablets | Yes | If redness spreads fast, or with a high temperature |
| Crusted, oozing bites from scratching | An antibiotic or antiseptic cream, or tablets | Yes | Not usually needed |
| A red, painful lump filled with pus | Assessment for draining | Yes, to assess | For draining |
| Swelling around the eye after a nearby bite | Urgent assessment | No | Urgent in-person care |
| Red streaks, a high temperature and feeling unwell | Urgent antibiotics, sometimes in hospital | No | Urgent care; call 112 if very unwell |
Not sure whether your bite is infected? A doctor can tell you in one consultation.
See available times →Treatment options for an infected insect bite
What you can do yourself
- Wash the bite gently with soap and water, and keep it clean and dry.
- Raise the area if you can, and hold a cold compress on it for swelling.
- Take paracetamol or ibuprofen for pain, and drink plenty of fluids.
- Do not scratch, squeeze or pop the bite, and keep your nails short.
Prescription treatment
A prescription is never issued without a consultation. If the bite is infected, the doctor may prescribe antibiotic tablets, usually for about a week, chosen after checking your allergies and other medicines, or an antibiotic cream for a small area of crusted skin. Symptoms can seem worse for the first 48 hours before they improve. If you are not feeling better 2 to 3 days after starting antibiotics, speak to a doctor again. If the doctor prescribes, use the prescription at a pharmacy near you.
What does not help
Antibiotics for a bite that is not infected: redness and swelling that start within hours of a bite are a reaction, and antibiotics do not ease them. Antihistamines ease itching but do not treat an infection. Home remedies such as bicarbonate of soda are not recommended.
How to stop a bite getting infected
Most infected bites start with scratching. These habits lower the risk:
- Wash new bites with soap and water.
- Ease the itch with a cold compress, an antihistamine or a mild hydrocortisone cream, instead of scratching.
- Keep nails short, and cover bites you tend to scratch at night.
- Keep cuts, scratches and bites clean until they heal.
Special situations
Diabetes or a weakened immune system
Skin infections can spread more easily. See a doctor promptly about a bite that is getting redder, hotter or more painful.
Bites on the face or near the eye
Swelling around the eye after a bite needs urgent in-person assessment, because infection near the eye can spread.
Pregnancy
Tell the doctor if you are pregnant, because it changes which antibiotics are suitable.
Bites while travelling
A high temperature, or a bite that does not heal, after a trip abroad needs a doctor, who will ask where you have been. Other holiday health problems are covered on the travel illnesses page.
Children
Mobi Doctor consultations are for adults aged 18 and over. A child who is unwell needs a paediatrician or a local doctor in person, and emergency signs in a child mean 112.
When an infected bite is treated online, and when you need in-person care
Treated online: telling an infection from a reaction, infected bites without fast-spreading redness or a high temperature, crusted bites, and follow-up during antibiotic treatment.
In-person care: fast-spreading infection, a high temperature with feeling unwell, swelling around the eye, an abscess that needs draining, and severe pain far worse than the bite looks.
When to get in-person care
Call 112 or go to an emergency department now for:
- spreading redness with a very high temperature
- a fast heartbeat or fast breathing
- purple patches on the skin, or cold, clammy or pale skin
- confusion, dizziness, fainting or being hard to wake
- swelling of the lips, face or throat, or difficulty breathing
Get medical advice the same day for:
- a bite that is getting hotter, more swollen and more painful
- red streaks spreading from a bite, or swollen, painful glands
- swelling around the eye, or a bite on the face that is spreading
- an infected bite if you have diabetes or a weakened immune system
- no improvement 2 to 3 days after starting antibiotics
How Mobi Doctor works
- Book a time that suits you: daily 7am–11pm CEST. You can see a doctor over video, usually within 15 minutes. No subscription, and the exact price is shown before you pay.
- Speak to a licensed doctor about the bite: show it on camera in good light, with the pen line around the redness, and say when you were bitten and how it has changed.
- Leave with a plan: what to do, what to take and for how long, and which signs mean you should be seen in person. If the doctor prescribes, use the prescription at a pharmacy near you.
No sign-up needed
Not sure it’s an infected bite? Tick every symptom you have to see each condition page that mentions it. It finds the right page, not a diagnosis: a doctor gives you that on a video call. If you have an emergency sign listed on this page, call 112 instead.
Tap the body — an area or a point — to browse symptoms anywhere
Similar symptoms, different condition? Cellulitis can start the same way. Compare them, or look up any other symptom in the full symptom checker.
Frequently asked questions about infected insect bites
How do I know if an insect bite is infected?
An infected bite gets worse instead of better: it becomes hotter, more swollen and more painful a day or more after the bite, and it may leak pus or crust. A high temperature or swollen glands also point to infection.
What does an infected insect bite look like?
A red or darker area around the bite that is spreading, feels hot and hurts, sometimes with pus, a yellow-brown crust or blisters. On brown and black skin, the redness can be harder to see, so feel for warmth and swelling.
Is a red, swollen bite always infected?
No. Redness and swelling that start within hours of a bite are an inflammatory or allergic reaction, not an infection. Large swellings can grow for 1 to 2 days and still not be infected. Most bites do not need antibiotics.
Do I need antibiotics for an infected insect bite?
Only if it is infected. A doctor can tell whether it is, and prescribe antibiotic tablets, or a cream for a small crusted area, chosen after checking your allergies and other medicines.
How long does an infected bite take to heal with antibiotics?
Symptoms can seem worse for the first 48 hours, then improve. Most people with a skin infection recover fully in 7 to 10 days. Speak to a doctor again if you are not better 2 to 3 days after starting antibiotics.
Can an infected bite heal on its own?
A slightly crusted bite can settle with cleaning, but a bite that is getting hotter, more swollen and more painful needs a doctor, because infection can spread into the deeper skin.
What can I do at home for an infected insect bite?
Wash the bite with soap and water twice a day, pat it dry, cover it with a clean dressing, keep the limb raised to reduce swelling, take paracetamol or ibuprofen, do not scratch or squeeze it, keep nails short, and draw a line around the red area with a pen so you can tell whether it is spreading. Take the full antibiotic course if one is prescribed. An infected insect bite should start improving within 2 days of antibiotics.
When is an infected bite an emergency?
With an infected bite, call 112 for spreading redness with a very high temperature, a fast heartbeat or breathing, confusion, purple patches on the skin, or cold, clammy or pale skin.
My bite is leaking fluid. Is it infected?
Fluid or pus coming out of a bite is one of the signs of infection, especially if the skin around it is also hot, red, painful and swelling. Wash it with soap and water, do not squeeze it, and have it checked by a doctor.
What does an infected mosquito bite look like?
Like any infected bite: a red or darker area around the bite that spreads, feels hot and hurts more each day, sometimes with pus or a yellow crust. A normal mosquito bite is small, raised and itchy, and starts to fade within a few days.
Which insect bites cause blisters?
Mite bites cause very itchy lumps that sometimes blister. Scratching a blister lets bacteria in, so keep blistered bites clean and covered, and see a doctor if the skin around them becomes hot, red or painful.
Which bites get infected most often?
Any bite can become infected, especially after scratching. Horsefly bites often become infected, and infection is more likely with diabetes, poor circulation or a weakened immune system.
How can I prevent an insect bite getting infected?
Wash a new bite with soap and water, use an antihistamine tablet or a mild steroid cream so the itch does not drive scratching, keep nails short and clean, cover a bite that is weeping with a plaster, avoid picking the scab, and keep insects off in the first place with repellent, covering clothing and nets. Most infected insect bites start with scratching, so controlling the itch in the first 2 days prevents most infections.
How do I tell an infected bite from a normal bite reaction?
Timing and the main symptom tell an infected insect bite from a reaction. A normal reaction starts soon after the bite, itches rather than hurts and settles, although redness and itching can last up to 10 days; a large local reaction swells within hours, grows for 1 to 2 days, then settles. An infected bite starts later, often after a day or more, gets hotter, more swollen and more painful, and may ooze pus, crust over or come with swollen glands and a high temperature.
Can an online doctor prescribe antibiotics for an infected bite?
Yes, when the bite is infected. A doctor can assess an infected insect bite on camera, tell infection apart from a strong reaction, and prescribe antibiotic tablets or cream, with the prescription usable at a pharmacy near you and never issued without a consultation. Redness spreading fast, a high temperature, or an infected bite on the face or near a joint needs in-person care, and the doctor tells you when.
- Insect bites and stings: antimicrobial prescribing (NG182), NICE, National Institute for Health and Care Excellence, 2020.
- Insect bites and stings, NHS, National Health Service (UK), reviewed 1 June 2023.
- Cellulitis, NHS, National Health Service (UK), reviewed 18 April 2024.
- Impetigo, NHS, National Health Service (UK), reviewed 6 June 2024.
- Insect sting allergy, Anaphylaxis UK, accessed 15 October 2026.
This page is for information only and is not a substitute for a medical consultation. Guideline links are provided for transparency; treatment decisions are made with your doctor.
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