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Dr. Chrysoula I. Liakou MD, PhD
- Treated online: Yes, for painful, swollen or infected bites; severe pain with muscle cramps, or a darkening wound, needs in-person care.
- How serious: most spider bites in Europe cause pain, redness and swelling, usually no worse than a wasp sting.
- False widows: the pain usually lasts 1 to 12 hours and rarely more than a day; a few bites cause stronger symptoms or an infection.
- The main risk: a skin infection in the days after the bite, so watch for spreading redness, warmth and pus.
- Emergency: call 112 for swelling of the face or throat, difficulty breathing, severe muscle cramps, chest pain, or spreading redness with a high temperature.
Do not book a video appointment if, after a bite, you have swelling of the lips, face or throat, difficulty breathing, severe pain spreading from the bite with muscle cramps, sweating, a rigid tummy or chest pain, or red, hot, spreading skin with a high temperature and feeling very unwell. Call 112 or go to an emergency department.
Can an online doctor treat a spider bite?
Yes. Most spider bites in Europe cause short-lived pain, redness and swelling, and a doctor can assess them by video: the bite, any spreading redness, and any symptoms away from the bite. The doctor can treat the pain, itching and infection. Severe pain with muscle cramps, or a bite that darkens into an open sore, needs in-person care.
How an online consultation helps with a spider bite
- Is it a spider bite?: Many suspected spider bites turn out to be skin infections or other bites, and the doctor looks for both.
- Infection checked: Spreading redness, warmth and pus mean infection, which may need antibiotics.
- Pain and swelling eased: Painkillers, an antihistamine or a steroid cream, chosen after the doctor checks your other medicines.
- Warning signs explained: Which changes over the next few days mean the bite needs to be seen in person.
What the doctor checks in an online spider bite consultation
The doctor checks for signs of a severe reaction first, then looks closely at the bite. The doctor asks about:
- Warning signs: swelling of the face or throat, breathing difficulty, muscle cramps, sweating, feeling sick, or pain in the chest or tummy.
- The bite: where and when it happened, whether you saw the spider, and how the pain has changed.
- The wound: a blister, a dark or bluish area, or an open sore.
- Infection: redness that is spreading, warmth, pus, swollen glands or a high temperature.
- Your health: your tetanus vaccinations, long-term conditions, pregnancy and the medicines you take.
If you can do so safely, photograph the spider or keep it in a sealed jar. A spider seen at the time of the bite is the only way to be sure that a spider caused it.
What does a spider bite look like?
There is no typical spider bite. Most cause sharp pain at the time of the bite, then redness and swelling at the site, much like a bee or wasp sting. The pain may spread out from the bite. Occasionally a bite causes an allergic reaction.
- Look: a red, inflamed bump, like other insect bites, sometimes with swelling around it.
- Itch and pain: the bump may itch or hurt, or you may not notice it at all.
- In the UK: most British spiders have fangs too small or weak to pierce human skin. The noble false widow can, and its bite causes local pain, which may spread out from the bite, and minor swelling.
- How long: the pain of a false widow bite usually lasts 1 to 12 hours, and rarely more than a day. Most people bitten by a Mediterranean black widow recover fully within a week, while a recluse wound can take weeks to months to heal.
How do you tell if a bite is from a spider?
Spiders rarely bite people, and only when they are trapped or pressed against the skin. Many marks blamed on spiders have another cause. In one study of 182 people who came to an emergency department with a suspected spider bite, 152, or 83.5%, had a skin infection instead. Lyme disease, other bites and skin conditions can also look like a spider bite.
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| What it is | How it starts | How it changes | What to do |
|---|---|---|---|
| Spider bite | Sharp pain at the moment of the bite, often with the spider seen | Redness and swelling, settling within a day or so | First aid |
| Skin abscess or cellulitis | A sore, red spot with no bite felt | Grows hotter, more swollen and painful over days, sometimes with pus | See a doctor |
| Infected insect bite | An itchy bite | Becomes red, hot and painful after a few days | See a doctor |
| Lyme disease rash | A red patch 1 to 4 weeks after a tick bite | Spreads slowly over days to weeks | See a doctor: antibiotics |
When should I worry about a spider bite?
Most spider bites need only first aid. See a doctor if, over the following hours or days, the pain becomes severe or keeps spreading, you get tummy cramps, the wound grows, blisters or turns dark, or redness spreads, with red streaks, warmth, pus or a high temperature. Difficulty breathing or swallowing needs 112.
False widow spider bites
Six species of false widow spider live in the UK. The noble false widow arrived in the 1870s, probably on cargo ships from Madeira and the Canary Islands, became established from the 1980s, mainly in the south, and has since spread north. It is also found in Ireland.
- How bad is the bite? The venom is not particularly potent, and a bite is usually no worse than a wasp sting.
- Symptoms: pain at the bite that may spread out from it, usually lasting 1 to 12 hours and rarely more than a day.
- Stronger reactions: a 2022 case series of 16 confirmed bites in Britain and Ireland, bringing the total in the medical literature to 24, describes some people with severe pain, tremors, tiredness, feeling sick and low blood pressure, and some bites that became infected, including cellulitis. Some people needed hospital care.
- When they bite: only when provoked or trapped against the skin. Males bite more often because they wander indoors looking for females.
Of the more than 650 spider species in the UK, about 12 have been recorded biting people. Reports of severe wounds after false widow bites are usually not backed by a confirmed spider, and are most likely due to an infection of a wound that was not kept clean.
How to identify a false widow spider
False widows have a dark, rounded body and are often mistaken for black widows. Six species live in the UK, and three are common. They are found indoors all year, and are seen more often in autumn:
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| Spider | Body length | What it looks like | Where you find it |
|---|---|---|---|
| Noble false widow | Females 8.5 to 14 mm, males 7 to 10 mm | A skull-shaped pattern on the back, clearer in males and sometimes missing in females; reddish to brown legs | High corners of rooms, kitchens and conservatories, with webs at least 1.5 m off the ground |
| Cupboard spider | Females 6.5 to 10 mm, males 4 to 6 mm | Dark, often purplish-brown, with longer front legs; markings often faint or missing | Low down indoors, under furniture and in dark corners |
| Rabbit hutch spider | Females 4.5 to 7 mm, males 4 to 5 mm | A band down the middle of the abdomen, and legs with more dark stripes than the others | Sheds, pet hutches and garden clutter |
The missing sector orb weaver, which lives in most UK homes and is not known to bite people, is often mistaken for a false widow.
Should you kill a false widow spider?
There is no need to. The Natural History Museum advises leaving false widows alone, or moving them outside, for example to a shed: they eat flying insects in the home, and they bite only when provoked or trapped against the skin. Females are slow and not aggressive.
Spider bites in southern Europe
Around the Mediterranean, only two species are considered medically significant, and the risk of serious harm is very low:
- Mediterranean black widow: local pain in about 9 in 10 bites, starting soon after the bite, with sweating, muscle cramps and spasms, and sometimes a rigid tummy that can feel like an emergency in the abdomen. Most people recover fully within a week, and deaths are rare.
- Mediterranean recluse: the bite is usually painless and often goes unnoticed. The area can become swollen and red, then blister and turn bluish or dark, and sometimes become an open sore that takes weeks to months to heal. Fever, nausea, headache and aching muscles are common, and in a severe form the venom affects the blood and kidneys, which needs hospital care.
Other spiders around the Mediterranean usually cause only mild symptoms, similar to a mosquito bite.
Which spider bite treatment might the doctor recommend?
Treatment depends on the symptoms, because the spider is rarely identified. This is the framework the doctors use:
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| What you have | Likely first step | Suitable for online care? | When in-person care is needed |
|---|---|---|---|
| Pain and swelling at the bite | Washing, a cold compress, painkillers and an antihistamine | Yes | Not usually needed |
| Pain spreading from the bite, sweating, feeling sick | Pain relief and a careful assessment | Yes, to assess | If pain is severe or muscles cramp |
| A blister or a dark area that is growing | Wound care and close follow-up | Yes, to assess | For wound assessment and dressings |
| Spreading redness, warmth or pus | Antibiotics | Yes | If it spreads fast, or with a high temperature |
| Severe muscle cramps, a rigid tummy or chest pain | Emergency treatment | No | Call 112 now |
| Swelling of the face or throat, difficulty breathing | Adrenaline and emergency treatment | No | Call 112 now |
Not sure whether it was a spider? A doctor can look at the bite on camera in one consultation.
See available times →Treatment options for spider bites
What you can do yourself
- Wash the bite well with soap and water, and keep it clean.
- Hold an ice pack wrapped in a cloth, or a cold, wet compress, on the bite, and raise the area if you can.
- Take paracetamol or ibuprofen for the pain.
- Take an antihistamine if the swelling is large or itchy, and try not to scratch.
Prescription treatment
A prescription is never issued without a consultation. The doctor may suggest a steroid cream for an inflamed, itchy bite, or prescribe an antibiotic if the bite is infected, chosen after checking your allergies and other medicines. Severe reactions to spider venom are treated in hospital. Controlled painkillers are never prescribed online. If the doctor prescribes, use the prescription at a pharmacy near you.
What does not help
Antibiotics do not help a bite that is not infected. Squeezing, cutting or sucking the bite can damage the skin and let in infection.
How to avoid spider bites
Spiders bite when they are trapped against the skin, so most bites can be avoided:
- Shake out clothes, shoes, towels and bedding that have been left on the floor.
- Wear gloves when you garden, move boxes or carry firewood.
- Move a spider out of the way with a glass and a sheet of card rather than your hand, and flick one off your skin rather than crushing it.
- Check the corners of sheds, garages and garden furniture before you reach in.
Special situations
Pregnancy
Tell the doctor if you are pregnant, because it changes which painkillers and other medicines are suitable.
Tetanus
If you are not up to date with your tetanus vaccinations, or are not sure, ask about a booster when a bite has broken the skin.
Holidays in southern Europe
A bite in the Mediterranean that is painless at first and then blisters or darkens over the next days needs a doctor to see it. 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 a spider bite is treated online, and when you need in-person care
Treated online: painful, itchy or swollen bites, infected bites without spreading redness or a high temperature, and advice on what to watch for over the next days.
In-person care: severe or spreading pain with muscle cramps or sweating, a blister or dark area that keeps growing, an open sore, fast-spreading infection, and any allergic reaction affecting breathing.
When to get in-person care
Call 112 or go to an emergency department now for:
- swelling of the lips, face, tongue or throat, or difficulty breathing
- severe muscle cramps, a rigid tummy, chest pain or a pounding headache after a bite
- confusion, fainting or collapse
- red, hot, spreading skin with a high temperature and feeling very unwell
Get medical advice the same day for:
- pain that is severe, or still spreading hours after the bite
- a bite that blisters, turns dark or becomes an open sore
- a bite that is red, hot, swollen and increasingly painful, or leaking pus
- fever, feeling unwell or dark urine in the days after a bite in southern Europe
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, share a photo of the spider if you have one, and say how the pain and swelling have 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 a spider 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.
Tap the body — an area or a point — to browse symptoms anywhere
Similar symptoms, different condition? Infected insect bite can start the same way. Compare them, or look up any other symptom in the full symptom checker.
Frequently asked questions about spider bites
What does a spider bite look like?
Usually like any other insect bite: a red, inflamed bump, sometimes swollen, that may itch or hurt. Most cause sharp pain at the time of the bite, and the pain may spread out from it.
Are spider bites itchy?
They can be. A spider bite is usually a red, inflamed bump that may itch or hurt, or go unnoticed. An antihistamine and a cold compress ease the itching, and scratching can let in infection.
Why do spiders bite, and which spiders bite in Europe?
Spiders bite only in self-defence, when they are trapped against skin in clothes, shoes or bedding or pressed by a hand, and most European spiders have fangs too small to pierce skin at all. The ones that can include the false widows, the woodlouse spider, the garden spider when handled, and, around the Mediterranean, the black widow and recluse. A spider bite that is not witnessed is often an insect bite or an infected hair follicle instead.
How do you tell if a bite is from a spider or something else?
Usually you cannot, unless you saw the spider. Many suspected spider bites are something else: in one emergency department study, more than 8 in 10 people who thought they had a spider bite had a skin infection.
Are false widow spider bites dangerous?
Rarely. A false widow bite is usually no worse than a wasp sting, with pain that lasts from 1 to 12 hours. A few people have stronger symptoms or an infected bite, so watch the bite for spreading redness, warmth and pus.
How do I identify a false widow spider?
False widow spiders have a dark, rounded body. The noble false widow, the most commonly reported, is 7 to 14 mm long, with a skull-shaped pattern on its back and reddish to brown legs, and often lives in high corners of kitchens and conservatories.
Should I kill a false widow spider?
There is no need. The Natural History Museum advises leaving false widows alone or moving them outside: they eat flying insects, and they bite only when provoked or trapped against the skin.
How long do spider bites last?
Most settle within a day or two, and the pain of a false widow bite rarely lasts more than a day. A bite that blisters, darkens or becomes an open sore can take weeks to heal and needs a doctor.
What should I do at home after a spider bite?
Wash the bite with soap and water, hold something cold on it, raise the area, and take paracetamol or ibuprofen for the pain. Keep the bite clean, and watch it over the next days for signs of infection.
When should I worry about a spider bite?
Worry about a spider bite when the pain becomes severe or keeps spreading, the wound grows, blisters or darkens, or redness spreads with warmth, pus, red streaks or a high temperature. Call 112 for difficulty breathing or swallowing, or severe muscle cramps.
Are there dangerous spiders in Europe?
Two spider species around the Mediterranean are medically significant: the Mediterranean black widow and the Mediterranean recluse. Serious harm is very rare, and most people recover fully with medical care.
Do spider bites need antibiotics?
Only when the bite is infected. Most spider bites need only washing, cold compresses and painkillers. A doctor can tell whether a red, painful bite is infected.
Can an online doctor treat a spider bite?
Yes, for most bites. A doctor can assess the bite on camera, treat pain, itching and infection, and tell you which signs need in-person care. Severe pain with muscle cramps, or a darkening wound, needs to be seen in person.
- How dangerous are false widow spiders?, Natural History Museum, London, accessed 15 October 2026.
- Fact sheet: false widow spiders (Steatoda spp.), Natural History Museum, London, 2014.
- Bites by the noble false widow spider Steatoda nobilis can induce Latrodectus-like symptoms and vector-borne bacterial infections with implications for public health: a case series, Dunbar JP et al., Clinical Toxicology, 2022.
- Spider bites of medical significance in the Mediterranean area: misdiagnosis, clinical features and management, Fusto G et al., Journal of Venomous Animals and Toxins including Tropical Diseases, 2020.
- Spider bites: symptoms and causes, Mayo Clinic, 2021.
- Spider bites, MedlinePlus, US National Library of Medicine, 2023.
- Insect bites and stings, NHS, National Health Service (UK), reviewed 1 June 2023.
- Falsehoods about false widows put to rest, Buglife, The Invertebrate Conservation Trust, 23 October 2013.
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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