Insect bites in the UK — identify what has bitten you with this ultimate guide

This guide covers the key things you need to know about insect bites in the UK. Note: Always consult a healthcare practitioner or doctor if you develop symptoms of a serious allergic reaction or for advice, official diagnoses and information on treating insect bites.

Covering eight of the most common biting insects in the UK, you’ll also find handy pictures of the offending critters and their bites making it easier to recognise them.

What's more we've also listed the most common insect hotspots to help you be prepared when you enter any habitats favoured by the little biters. 

A note on medical advice about insect bites in the UK

Of course, this guide does not constitute medical advice. Always seek the advice of your health practitioner or doctor if you develop symptoms of a serious allergic reaction or for advice, official diagnosis and information on treating insect bites.


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An introduction to insect bites in the UK

The summer holidays are here, and families up and down the country are brushing off their BBQs, airing those sleeping bags and untangling the guy ropes, ready to enjoy the great outdoors. 

But it’s not just misplaced tent pegs and mildewed groundsheets that can get right under a camper’s skin. Thriving in Britain’s typically warm, wet and damp summer weather conditions, there are some tiny critters that inevitably share our rolling green hills (and towns for that matter) with us, and some of them love nothing more than to feast on our unwitting skin.

While most insect bites are more of a nuisance than harmful, some can cause particularly nasty side effects. But as anyone who has had to contend with a swarm of incessant mosquitoes or midges will testify, constantly swatting away flying insects and other creepy crawlies can really spoil that much anticipated picnic or camping trip.

So, who are the main culprits most likely to take a bite out of your fun in the sun (or overcast day for that matter) and where do the little critters like to hang out? How do you tell a mosquito bite from a midge bite? More importantly, what can you do to protect yourself other than wearing a spacesuit?

This handy guide sheds light on what you need to know about insect bites from mosquitoes, ticks, midges and leeches, to stable flies, horse flies, sand flies and black flies.

1. Insect bites from mosquitoes

Let’s kick off with the mighty mosquito. These pesky insects may be tiny but can pack a pretty big and irritating punch with their insect bite. A real nuisance that loves to enjoy the warm weather as much as we do, mosquitoes are actually present for at least 6 months of the year in the UK, from as early as April and May.

Where are mosquitoes found in the UK?

In the UK, mosquitoes exist all over the country. They thrive in warm, damp conditions, as well as by areas of standing water such as lakes, pools, marshes and wetlands which offer perfect breeding conditions for them. Take care too near ditches, man-made lakes on golf courses and even near your eco-friendly water butt and the dog’s water bowl in the back yard. They are also particularly fond of warm grassy areas to hide in. Be aware their internal body clock actually kicks in at dawn and dusk telling them it is feeding time so be extra vigilant for mozzies at these times too!

How to identify a mosquito

The aedes aegypti mosquito - source Mosi-guard

The aedes aegypti mosquito - source Mosi-guard

There are many species of mosquito which can vary in appearance. Most have:

  • wings with a fringe-like border which are longer than its body
  • hollow, straw-like extending mouthparts
  • a hunched back appearance

Signs and symptoms of insect bites from mosquitoes

What mosquito bites look like.  Image source :

What mosquito bites look like. Image source:

Common symptoms of mosquito bites include soft bumps on the skin that may become pink, red, and very itchy. Note that these symptoms may occur up to 48 hours after the initial insect bite.

Symptoms of a more severe allergic reaction may include a large area of itching, lesions or bruises near the site of the insect bite.

How to avoid insect bites from mosquitoes

  • Buy and use a mosquito repellent from April through to October in the UK 
  • Take extra care at dawn and dusk and near wooded areas, damp grassy spots and standing water
  • Cover up with cool, comfortable clothing whilst using a mosquito repellent on any exposed skin
  • Apply an even thin layer of mosquito repellent proven to protect against a range of mosquitoes and reapply if you’re perspiring, jumping in and out of a pool or using water pistols
  • Keep those tent and caravan windows closed or cover openings with a mosquito net

2. Insect bites from ticks

These eight-legged tiny parasites feed on the blood of humans and animals and some ticks are capable of transmitting infections such as Lyme Disease which affects at least 3,000 Brits every year.

Where are ticks found in the UK?

The UK already has a growing population of ticks well established in our countryside and rural areas as well as urban suburbs and towns. Experts have also warned they are on the increase. Areas with good vegetation, dense woodland and thick grass tend to be their habitat of choice, in addition to areas frequented by wildlife, deer and livestock. UK tick hotspots are reported to include the Highlands and Islands of Scotland, the New Forest, Exmoor, the South Downs, Thetford Forest, the Lake District and the North Yorkshire Moors.

How to identify a tick

A Deer tick - source Mosi-guard

A Deer tick - source Mosi-guard

Ticks are not actually insects but Arachnida, part of the spider family. They can vary in colour from shades of brown and red, to black. To the naked eye the larvae (with 6 legs) look like specks of soot. With their eight legs, nymphs and adult ticks resemble small spiders. It is the nymph which is most likely to bite you, which may be no bigger than a poppy seed.

Signs and symptoms of insect bites from ticks

Ticks love warm, moist areas of the body such as the armpits or groin. Once a tick has found its way onto your body, and bitten into your skin it draws blood. Ticks normally remain attached to your body after they bite you meaning many people only realize they have been bitten by a tick after finding one still attached. After a period of several days or weeks of drawing blood from your body, an engorged tick can detach itself and fall off.

A tick bite. Image source  webmd

A tick bite. Image source webmd

A tick bite with bulls-eye rash. Image source:  Wikipedia

A tick bite with bulls-eye rash. Image source: Wikipedia

Tick bites are usually harmless and may produce no symptoms. However, if you are allergic to tick bites, you may experience pain or swelling at the bite site, a rash, burning sensation, blisters, or even difficulty breathing.

Early symptoms of Lyme Disease can comprise a ‘bulls eye’ skin rash around the bite, and ‘flu-like’ symptoms such as headache, weakness, muscle pain, fever and exhaustion. Longer term, chronic effects can include memory loss, numbness and joint problems. It is important to seek medical advice and/or treatment early if you have been bitten by a tick and develop any of these symptoms.

How to avoid insect bites from ticks

  • Take extra care in wooded areas and dense undergrowth where ticks can thrive
  • Apply a thin, even layer of an effective repellent. Mosi-guard Natural with its active ingredient Eucalyptus citriodora oil hydrated, cyclized EC Oil (H/C) derived from lemon eucalyptus oil - has been proven to provide effective protection against a wide range of tick species, including those that carry Lyme disease.  A single application provides long lasting protection from ticks (and other biting insects).
  • Cover up with long clothing especially on legs and arms and tuck trousers into socks.
  • Check yourself (and pets) carefully for ticks after being outdoors, especially warmer parts of your body, i.e. behind the knees
  • Remove any ticks carefully, as soon as possible with a tick-remover. Never compress the tick’s body or leave the mouthparts in the skin as this increases the chance of infection

If you are bitten by a tick, follow these steps for tick removal.

3. Insect bites from midges

Ah, the mithering midge, or gnat. Often travelling in packs, or swarms, midge bites don’t transmit illness but they’re often painful, itch intensely and can swell up alarmingly. It’s thought midges can home in on carbon dioxide sources from up to 200 metres away which helps them zoom in on their next meal.

Where are midges found in the UK?

The bane of the summer evening, midges feature throughout the UK. The Scottish Highlands in particular are known to be a midge magnet due to the climate and landscape. Midges tend to make an appearance on damp and cloudy summer days. They are big fans of wet ground such as near estuaries, marshes and tidal flats. They also love dense undergrowth and like their pals the pesky mosquitoes, they love dawn and dusk conditions.

How to identify a midge

A midge. Image source  Wikipedia

A midge. Image source Wikipedia

The adults are gray and less than 1/8 inch long. Their two wings are often very hairy and pigmented.

Signs and symptoms of insect bites from midges

Midge bites. Image source Scottish Biz

Midge bites. Image source Scottish Biz

Bites will often form as small lumps which are usually very itchy. You may also be able to see a small hole within the lump. If you're particularly sensitive to insect bites, you may develop fluid-filled blisters or weals, surrounding the bite.

How to avoid insect bites from midges

  • Midges and gnats tend to attack in swarms, especially in hot weather, so use an insect repellent to avoid bites
  • Cover up at dawn and dusk in light coloured clothing, as dark clothing attracts them
  • Believe it or not midges can detect carbon dioxide in your breath 200 metres away so if you are doing any physically exerting activity such as hill walking always wear repellent and reapply if you are perspiring.

4. Bites from leeches

A rather less common biting (or should we say sucking) adversary in the UK, leeches are a type of segmented worm, the appearance of which is likely to send a shudder down many a spine. Interestingly, they are hermaphrodites, meaning they have both male and female reproductive organs. There are literally hundreds of species of leech.

Where are leeches found in the UK?

When people think of leeches, often they associate them with wet rainforests and tropical lagoons. While many leeches do prefer fresh or marine water, there are varieties of these creepy crawlies which can dwell on land. These tend to prefer damp areas, such as moist soil and low foliage on paths or trails where they wait for their next warm-blooded meal which they detect by vibration or odour. A particular hotspot is believed to be the low lying marshes on the South Eastern corner of the UK Romney Marsh which is on the Kent / Sussex border and in other wetland areas of Kent.

During the dry season, these leeches often burrow themselves in the ground, where they hibernate even without water. They simply shrivel up and become rigid and their bodies become very dry, reviving to their former state once sprinkled with water.

How to identify a leech

A land leech - image source:  The Telegraph

A land leech - image source: The Telegraph

   A land leech biting. Image source  Wikipedia


A land leech biting. Image source Wikipedia

Leeches are a type of segmented worm characterised by a small sucker on the anterior (mouth) end of the cylindrical flattened body, and a larger sucker on the posterior end.

Signs and symptoms of bites from leeches

Leeches are super wiley at gaining access to your skin and have been known to crawl through shoelace holes. Once a leech has bitten you, they secrete an anticoagulant which makes the bite painless. Often, people notice a small blood stain on clothing before finding a leech.

How to avoid bites from leeches

  • Spray an effective repellent onto your socks and boots making sure it is formulation that is DEET free, as DEET has been known to damage rubber and plastics.
  • Opt for long sleeved clothing with a tight weave fabric
  • Protect, protect, protect, and buy a good insect repellent

How to remove a leech

  1. Identify the oral sucker found at the small end of the leech
  2. Put your finger on your skin next to the oral sucker
  3. Gently and firmly slide your finger toward the wound from where the leech is feeding
  4. With your fingernail push the sucker sideways away from your skin
  5. Quickly detach the rear (fatter end) of the leech from your skin (be aware it will try to reattach itself while you do this)
  6. Keep the wound clean

Removing a leech by burning it or by applying alcohol is actually an old wive's tale and can result in the leech regurgitating into the wound which can introduce infection.

5. Insect bites from stable flies

Often confused with the common housefly, stable flies are also known as biting flies. However, unlike other flies, the stable fly sucks blood from mammals.

Where are stable flies found in the UK?

Stable flies are prevalent across the world, particularly around livestock and equine livery yards, where the animal manure and wet straw offer them the perfect breeding ground. Stable flies can also be found near the sea shore, and loitering near outdoor dog kennels. They tend to prefer the outside environment to indoors.

How to identify a stable fly

A stable fly. Image source  You Tube

A stable fly. Image source You Tube

The stable fly is about 6 or 8 mm long with four distinct, dark longitudinal stripes on its body and several dark spots on the abdomen. It has sharp mouthparts protruding from the head.

Signs and symptoms of insect bites from stable flies

A stable fly bite. Image source  nomogaia

A stable fly bite. Image source nomogaia

Stable flies can deliver a very painful bite which can sometimes feel like a needle. They can be extremely persistent and tend to attack around the ankles and lower legs.

How to avoid stable fly bites

  • If you’re a horse owner or working with livestock ensure to keep manure and wet straw to a minimum as stable flies breed in these environments
  • Buy and use a quality insect repellent to ward off bites

6. Insect bites from horse flies

These are large hairy little beasts and while they do not carry diseases, their bite can be very painful. They favour warm, sunny days to search for their next meal.

Where are horse flies found in the UK?

Adult horse flies are fast, strong fliers usually found around streams, marshes, and wooded areas. They are also very persistent meaning simply swatting them away does not work. They will be back! In fact many often give chase to their intended targets for a short time so be sure to use a good repellent for some added protection.

How to identify a horse fly

A horse fly - image source  Wikipedia

A horse fly - image source Wikipedia

Horse flies are dark, almost black in color with very large, prominent eyes which they use in hunting.

Signs and symptoms of insect bites from horse flies

A horse fly bite. Image source  Wikipedia

A horse fly bite. Image source Wikipedia

They tend to attack the head and upper body with their bites. Their nips can prove very painful as their bite cuts the skin rather than piercing it. This is why horse fly bites can take longer to heal than other insect bites. This also means horse fly bites can easily become infected. As well as the formation of a weal around the bite, you may also experience a rash of weals (hives).

How to avoid insect bites from horse flies

7. Insect bites from sand flies

It is the female of these tiny midges which is the biter, drawing on the protein of the blood she needs to produce her eggs. Sand fly is a colloquial name for any species of biting flies encountered in sandy areas. Other names include "greenheads", biting midges, sand gnats or sandfleas.

Where are sand flies found in the UK?

As the namesake suggests, sand flies do indeed prefer to loiter around sandy areas where there is also flowing water and foliage. So think sandy shores, tidal estuaries, and marshes. You might find a sand fly resting on fences or vegetation waiting for their next meal. Weather wise they love dull still days with high humidity.

How to identify a sand fly

A sand fly: image source  Wikipedia

A sand fly: image source Wikipedia

Like the midge they are very small so this can be difficult.  If it looks like a fly but it’s too small to see the wings, it is probably a sand fly or a midge.

Signs and symptoms of insect bites from sand flies

A sand fly bite - image source  Wikipedia

A sand fly bite - image source Wikipedia

Sand fly bites can leave large, raised red itchy bumps that may turn into a rash. These bumps can be just as itchy as mosquito bites and may well last longer too. They can also be vectors of some diseases including leishmaniasis and pappataci fever; both often referred to as sand fly fever.

How to prevent sand fly bites

  • Don’t believe everything you read in that only DEET is effective against sand flies. Eucalyptus citriodora oil hydrated, cyclized EC Oil (H/C) derived from lemon eucalyptus oil has been shown to be very effective against sand flies, providing 8 hours of protection against insect bites.
  • Always take extra precautions if you are heading to a sand fly hotspot such as wearing protective (long sleeved) clothing

8. Insect bites from black flies

The black fly belongs to a large family with over 1800 known varieties. Most black flies gain nourishment by feeding on the blood of mammals, including us, although the males feed mainly on nectar.

Where are black flies usually found in the UK?

They tend to feed in the daytime, normally when wind speeds are low. The Blandford fly (Simulium posticatum) in England was once a public health problem in the area around Blandford Forum, Dorset, due to its large numbers and the painful lesions caused by its bite.

In parts of Scotland, various species of black flies are a nuisance and bite humans, generally between May and September. They are found mainly in mixed birch and juniper woodlands, and at lower levels in pine forests, moorlands, and pastures.

Mature adults can disperse tens or hundreds of kilometers from their breeding grounds in fresh flowing water. The fact they fly in swarms can make outdoor activities unbearable. Biting flies feed during daylight hours only and tend to zero in on areas of thinner skin, such as the nape of the neck or ears and ankles.

How to identify a black fly

A black fly. Image source  Wikipedia

A black fly. Image source Wikipedia

They can usually be identified by their black or gray bodies, short legs and antennae. A black fly is about the size of a small mosquito but can be up to 1/2 inch in length. It is much more bulbous and darker than a mosquito.

Signs and symptoms of the black fly bite

A black fly bite. Image source  BioDiversity in Focus

A black fly bite. Image source BioDiversity in Focus

Bites are most often found on the head, neck, and back. They also frequently land on legs and arms too. Black fly bites tend to be shallow but sore as they use a cutting technique to bite your skin. You may not feel the bite at the time as they introduce an anticoagulant via their saliva, which also partially numbs the site of the bite.

Itching and inflammation can appear at the site of a bite and swelling can be quite pronounced depending on the species of black fly. Irritation can last for a number of weeks especially if it was a prolonged bite.

How to avoid black fly bites

  • Avoid areas inhabited by the flies
  • Avoiding peak biting times
  • Wear heavy-duty, light-colored clothing, including long-sleeve shirts, long pants and hats.
  • Yes…you guessed it, buy and wear an insect repellent proven to protect against these biters

Simple precautions against insect bites in the UK

So there you have it, a list of the most common biting insects you are most likely to encounter outdoors in the UK. By taking a few simple precautions such as identifying insect hotspots, wearing appropriate clothing, and applying an effective repellent which protects against a wide range of biting insects you can really relax and enjoy all that the great outdoors has to offer.

Note: Always consult a healthcare practitioner or doctor if you develop symptoms of a serious allergic reaction or for advice, official diagnoses and information on treating insect bites.