Tick bites and Lyme disease

Ticks are small blood-feeding arachnids, related to spiders, found throughout the UK. They are most active from spring to autumn but can be encountered in any month. Most tick bites cause nothing at all. A minority transmit infection, and the one that matters most here is Lyme disease.

Almost everything that determines the outcome of a tick bite comes down to two things: finding it, and removing it properly and soon.

Where ticks actually are

This is worth correcting first, because the common picture is wrong in a way that sends people looking in the wrong place.

Ticks do not live in trees and do not drop from them. They cannot fly or jump. They sit on vegetation at roughly ankle to knee height, front legs outstretched, and climb onto whatever brushes past. So the risk is in long grass, bracken, heather, leaf litter and the vegetation at the edges of paths — not in sitting under a tree, which older advice warns against for no reason.

Habitats include woodland, grassland, moorland and heathland, and also some urban parks and gardens. In the UK the species responsible for most human bites is the sheep tick, Ixodes ricinus, which despite the name feeds on deer, sheep, small mammals, birds and people. Deer populations are a major factor in how many there are locally.

Ticks are present across the whole of the UK, with higher densities in parts of southern England, the South West, East Anglia and the Scottish Highlands. Writing that describes Lyme disease as an American problem found "even in Europe", and names the American deer tick as the culprit, is describing a different continent's situation.

Size matters for spotting them. A larva is about the size of a freckle, a nymph — the stage responsible for most human infections — is about the size of a poppy seed, and an adult female that has fed can be as large as a small bean. The small ones are what get missed.

Removing a tick

This is the single most useful thing on the subject and it was entirely absent from older writing here, which said only that people should "know how to remove it".

Ticks do not burrow under the skin. They attach by inserting barbed mouthparts and cement themselves in place, so what is visible is the body with the head buried at the surface.

1. Use fine-tipped tweezers or a proper tick removal tool. A tick tool costs very little and is better than tweezers, particularly on a nymph.
2. Grasp the tick as close to the skin as possible — by the head end, not the swollen body. Squeezing the body can push its gut contents into the bite.
3. Pull upwards, slowly and firmly. Straight out. Do not twist, jerk or wrench.
4. Clean the bite with soap and water or an antiseptic wipe afterwards, and wash hands.
5. Note the date, and watch the site for several weeks.

If a fragment of mouthpart stays behind, it is a splinter rather than an infection risk — leave it, and it will work its way out. A small red mark at the bite site for a few days afterwards is normal and is not Lyme disease.

What not to do, all of which are traditional and all of which make the tick more likely to regurgitate into the wound: burning it with a match or cigarette, smothering it with petroleum jelly, nail varnish, alcohol or oil, and twisting it out with fingers. Waiting for it to drop off is also a poor plan — the risk of transmission rises the longer it stays attached, so prompt removal is the point.

Pets bring ticks indoors and get them themselves. A tick removal tool used on the dog is the same tool.

What ticks carry in the UK

Lyme disease — infection with Borrelia bacteria — is the main one, and the proportion of ticks carrying it varies a good deal by area. Only a small minority of bites lead to infection, and transmission usually requires the tick to have been attached for many hours, which is why removing it quickly helps.

Tick-borne encephalitis has been found in ticks in a small number of English locations in recent years, with a handful of human cases. The risk in the UK is very low, and it is mentioned here because it is new rather than because it is likely. It is a real risk in parts of central and eastern Europe and Scandinavia, where a vaccine exists and is worth asking about before a walking or camping holiday.

The rash that decides the treatment

The characteristic early sign of Lyme disease is erythema migrans, a spreading circular or oval red patch that appears at the bite site, typically one to four weeks afterwards and sometimes up to three months.

What it looks like is frequently misdescribed:

• It expands slowly over days, which is the key feature — a reaction that appears within hours and settles is not this.
• It is usually neither itchy nor painful, and not usually warm, which distinguishes it from an ordinary bite reaction and from cellulitis.
• It may develop a clearer centre, giving a target or bull's-eye appearance — but frequently does not. Waiting for a bull's-eye before taking it seriously is a common and consequential mistake. A uniformly red expanding patch is just as much erythema migrans.
• It can be large — the size of a hand or bigger.
• It occurs in many cases but not all, so its absence does not rule Lyme disease out.

Alongside or instead of the rash, early Lyme disease can produce a flu-like illness out of season: fever, headache, fatigue, aching muscles and joints, and swollen glands.

Erythema migrans is treated on sight, without waiting for a blood test. This is the most important clinical point and it is worth knowing before an appointment. Antibody tests are frequently negative in the first weeks because the body has not yet produced the antibodies the test looks for, so a negative result at that stage proves nothing. UK guidance is explicit: where the rash is present, treatment starts.

Blood testing has its place later, where the rash is absent and the picture is less clear, and sometimes needs repeating after a few weeks.

Treatment

A three-week course of oral antibiotics — usually doxycycline, or amoxicillin where doxycycline is unsuitable, as in pregnancy and in young children. Treated early, the great majority of people recover fully.

One thing to expect, because it causes people to stop their tablets: in up to about one in seven, symptoms get temporarily worse in the first day of treatment — fever, chills, aching, headache — as the bacteria are killed. It settles within a day or two and is not an allergic reaction. Unless there is a rash of hives or any difficulty breathing, the course should be continued.

Antibiotics after a tick bite, before any symptoms, are not recommended in Europe. The exception is someone with a significantly suppressed immune system, where a single dose may be considered within seventy-two hours of removal. For everyone else the right approach is removal, then watching the site and their own health for a month.

Untreated, Lyme disease does not reliably "go away and recur", as older writing suggested. The early rash does fade on its own, which is a different thing — the infection can persist and cause later problems. Those include facial palsy, severe nerve root pain, a meningitis-like illness with headache and neck stiffness, swelling of one or two large joints, and, uncommonly, heart rhythm disturbance. All of these are treatable and all need specialist input.

The contested part, honestly

Some people have symptoms that persist after treatment — fatigue, pain, difficulty concentrating. UK guidance acknowledges this explicitly and says such symptoms should be taken seriously and the person assessed rather than dismissed.

What is not supported by evidence is the package often attached to it: diagnosis by unvalidated laboratory tests sold privately, and prolonged or repeated courses of antibiotics. Trials of extended antibiotic treatment have not shown benefit, and long courses carry real harm. Some of the private tests marketed for Lyme disease return positive results in people who do not have it.

That leaves a genuinely unsatisfactory situation for people who are unwell, and it is not resolved by either side pretending otherwise. The practical advice is to be seen through the NHS route, to ask for referral where symptoms persist, and to be wary of anybody selling a test and a treatment together.

Avoiding bites

• Keep to clearly defined paths rather than pushing through vegetation. This is the most effective measure and the easiest.
• Cover the legs — long trousers, tucked into socks for anything overgrown, and closed shoes rather than sandals.
• Light-coloured clothing, so a tick is visible and can be brushed off before it attaches.
• Insect repellent containing DEET on exposed skin, and permethrin-treated clothing for anyone spending long periods in tick country.
• Check thoroughly during the day and again at home. The places ticks favour are the warm, folded and hidden ones: behind the knees, the groin, the waistband, armpits, the navel, behind the ears, the hairline and the back of the neck. Children need checking by somebody else, particularly the scalp and hairline, where their bites concentrate.
• Check pets, and keep them treated.
• Clothing can be tumble-dried hot, which kills ticks more reliably than washing does.

None of this is a reason to stay indoors. Walking in the countryside is good for people, the risk from any single bite is small, and the measures above reduce it considerably at almost no cost.

When to see a GP

• Any spreading circular or oval red patch appearing days or weeks after time outdoors — whether or not a bite was noticed, and whether or not it has a target pattern. This is the one to act on promptly.
• A flu-like illness, unexplained fatigue, or aching joints and muscles within a few weeks of being outdoors in tick country.
• Facial weakness or drooping, severe headache with neck stiffness, nerve pain, or a swollen knee.
• A bite site that becomes hot, painful, swollen and spreading over a day or two, which is more likely ordinary skin infection than Lyme disease but needs treating.
• A tick bite in anyone with a suppressed immune system, promptly, because preventive treatment may be offered within the first three days.
• After a tick bite abroad, mentioning where — different regions carry different infections.

It is worth saying at any appointment that there has been a tick bite or time spent outdoors, because the illness is easily mistaken for something ordinary and the travel or exposure history is often what prompts the right test.