Lyme disease toolkit

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This toolkit is a user-friendly guide to Lyme disease for general practitioners and other healthcare professionals.


Lyme disease is a bacterial infection caused by the spirochaete Borrelia burgdorferi. It occurs worldwide, is increasing in incidence and is the most common tick-borne disease in the northern hemisphere. Whilst early recognition and treatment lead to resolution of the illness for many patients, late or missed diagnosis may result in persistent, debilitating symptoms.

Lyme disease symptoms may be non-specific and difficult to recognise. Raising awareness amongst primary care clinicians will increase the likelihood of patients receiving early and effective treatment. Clinicians should be aware of the genuine scientific uncertainties and ongoing research in relation to both diagnosis and treatment of this disease.

This toolkit is a user-friendly guide to Lyme disease for general practitioners and other healthcare professionals. Patients and the public may also find it helpful.

  1. Lyme disease, also known as Lyme borreliosis, is a zoonotic bacterial infection caused by the spirochaete Borrelia burgdorferi, transmitted via the bite of an infected tick.
  2. It is the most common tick-borne disease in the northern hemisphere and is increasing in incidence. It can affect adults and children of any age.
  3. Ticks, the vector for Lyme disease can be found throughout the UK and Ireland - in urban parks and gardens as well as rural areas.
  4. Ticks feed on and are carried on wild mammals and birds. Their bite is usually painless. They can be very small and may go unnoticed.
  5. Prompt correct tick removal decreases the risk of infection. There is no proven minimum time of attachment needed for transmission of infection.
  6. An erythema migrans (EM) or bull’s eye rash is diagnostic. It may be atypical and may be absent in at least 30% of cases. Serology is not required. Antibiotic treatment should be initiated - as per NICE guidance NG95.
  7. Early symptoms may be flu-like and non-specific (with or without an EM rash).
  8. Diagnosis can be difficult and should be based on a detailed clinical history (including travel history) and examination.
  9. Lyme serology tests may be unreliable, especially in early disease. A negative test does not exclude the diagnosis. There is no test of disease activity or cure.
  10. Early diagnosis and adequate treatment provide the best chance of cure. Late diagnosis and inadequate treatment may result in continuing health problems.
  11. There is no international consensus on the required duration of treatment.
  12. There is no international consensus on the cause and management of persistent symptoms.

Image of EM rash

Erythema migrans

Lyme disease, or Lyme borreliosis, is named after Old Lyme, a town in Connecticut, USA. In the 1970s, lots of children developed symptoms similar to juvenile arthritis in the town. However, its dermatological and neurological manifestations have been recognised in Europe since the late 1800s. Bannwarth’s syndrome, lymphocytic meningo-radiculitis, was described in 1941. A variant of Borrelia burgdorferi DNA has since been identified in the ice-age mummy, Ötzi.

There are many species of Borrelia worldwide, and those which cause Lyme disease are referred to as Borrelia burgdorferi sensu lato (Bbsl). In the UK, there are three main genospecies known to cause Lyme disease and symptoms may vary depending on the species:

  • Borrelia garinii (Bg) is associated with neurological conditions
  • Borrelia afzelii (Ba) is associated with skin and atypical neurological presentations
  • Borrelia burgdorferi sensu stricto (Bbss), may cause Lyme arthritis, especially of large joints such as the knee

Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the USA. The American strains of Bbsl are thought to cause a more severe inflammatory reaction, and have been associated with fatal Lyme carditis.

1. Epidemiology

Lyme disease occurs throughout most of the world and is the most common tick-borne disease in the Northern hemisphere. The incidence has been increasing, possibly due to climate change, changes in land management and biodiversity, as well as increased awareness. In the UK official figures only include laboratory-confirmed cases, and do not include those diagnosed clinically. Some cases may also be misdiagnosed or go unreported, so the official figures are known to underestimate the true scale of the problem.

A proportion of cases are contracted after foreign travel. The recorded incidence of Lyme disease is higher in continental Europe compared to the UK, especially eastern European countries. The North-Eastern USA and West Coast are also highly endemic areas.

2. Ticks and Tick Bites

A. Ticks
  • Ticks are small blood-sucking arthropods that are found across the UK.
  • Ticks hatch and moult through three life stages: larva, nymph and adult.
In the UK, Lyme disease can be transmitted to humans by at least three species of hard-bodied tick belonging to the Ixodes complex:
  • Ixodes ricinus or sheep tick
  • Ixodes hexagonus or hedgehog tick, which may inhabit urban areas
  • Ixodes canisuga: the fox tick, also known as the dog tick
  • N.B. Ixodes scapularis is the deer tick, a native American species, not found in the UK
  • Ticks need humidity and shade to survive. They are found in woods, fields and moorland but may survive in urban parks and gardens if conditions are suitable, including areas of Central London.
Ticks are more active from April to October but may remain so throughout the year in warmer parts of the UK. The incidence of Lyme disease peaks in June, with a smaller peak in September, reflecting increased tick activity. In the UK limited studies have shown that only a proportion of ticks, between 0-12% may be infected with the Lyme bacteria

Image of a tick life cycle

Images of UK ticks

Information from LDA

B. Tick exposure outside the UK
Enquiry about travel history is important when assessing the risk of Lyme disease. Higher tick infection rates are reported from mainland Europe and parts of North America. The recorded incidence of Lyme disease is particularly high in Central and Eastern Europe and Northeastern States of the USA. Ticks may carry a range of other bacteria, viruses and parasites, though recorded cases of other tick-borne diseases have only rarely been recorded in the UK.
European tick maps
USA tick maps
Tick awareness is an essential part of Lyme disease prevention.
Advice on avoidance and prevention of tick bites includes:
  • Avoid brushing against vegetation
  • Wear long trousers and tuck them into socks
  • Wear light coloured clothing so that ticks are more easily noticed
  • Carry out tick checks - especially on children and domestic animals
  • Prompt correct tick removal is key to primary prevention of Lyme disease.
  • Insect repellents containing DEET and picardine are effective against ticks.
  • Pet owners are one and a half times more likely to be bitten by a tick than non-pet owners. (Animals may carry ticks into the home.)

Public Health England - Lyme disease prevention

Public Health England tick awareness leaflet

Tick bite prevention and management

Preventing tick bites - image

C. Tick bite management
  • Only one in three people are thought to notice a tick bite
  • Nymphs, the stage most likely to bite humans, may be as small as a poppy seed so may not be noticed.,/li>
  • Ticks feed and may remain firmly attached for up to five days in order to take a blood meal. Tick saliva contains anti-inflammatory and anti-clotting agents, so the bite may not be itchy or painful.
  • Adults tend to be bitten on the lower body such as behind the knee, the groin or the navel, whereas children may be bitten on the upper body, especially around the hairline.
  • The statistical risk of a person developing Lyme disease from a tick bite in the UK is thought to be low. However, it only takes one bite from an infected tick for infection to be transmitted, especially if the tick remains attached for long enough to become engorged. There is no proven minimum time of attachment required for transmission of infection.
  • Ticks should be removed promptly and carefully using fine-tipped tweezers or a tick removal tool. Do not use oil or nail varnish. Avoid squashing the tick.
  • A person who has been bitten by a tick should remain vigilant for signs of skin rashes, flu-like symptoms or other unusual symptoms for at least 30 days following the bite and seek medical attention if necessary.

Images of attached ticks

three images together showing ticks

LDA guidance on tick removal

3. Clinical Features

Clinical signs and symptoms of Lyme disease may be non-specific and atypical. The clinician should enquire about recent or past tick exposure, tick bites or possible erythema migrans rash. A high index of clinical suspicion may be needed to make the diagnosis.

Erythema migrans

An EM (bull’s eye) rash is diagnostic but may not be present in around 30% of UK Lyme patients. It usually develops within three to 30 days of a tick bite, but may take longer. It may appear as an area of uniform redness rather than a ‘bull’s eye’ and is typically painless and not itchy. It will usually present at the site of the bite, however in early or late disseminated disease there may be multiple, sometimes transient, erythema migrans rashes on other areas of the body.

An EM rash may resolve spontaneously without antibiotic treatment. However this does not indicate that the infection itself has resolved. If left untreated the disease may disseminate around the body.

A small localised area of redness may occur in response to a tick bite but this usually resolves in -5 days and is probably not an indication of Lyme disease.

Two images of what Erythema migrans look like on an arm. A small localised area of redness may occur in response to a tick bi

Systemic symptoms

The infection may disseminate around the body at an early stage of the disease. It may result in a multi-systemic illness involving the nervous system, joints, skin, heart and eyes. Lyme disease is known to adversely affect the immune system which may result in a relapsing-remitting clinical picture, often characterised by pain and fatigue.

Symptoms may resemble many other conditions such as facial palsy, ME/CFS, fibromyalgia, polymyalgia rheumatica, MS, motor neurone disease, carditis, meningitis, encephalitis, auto-immune conditions or neuropsychiatric problems.

In the UK and Europe, disseminated Lyme disease is more likely to affect the nervous system, (peripheral, central and autonomic), with the potential to cause a wide range of diverse neurological symptoms. Lyme arthritis is more typically seen in North America.

Early diagnosis and adequate treatment provide the best chance of cure. Late diagnosis and inadequate treatment may result in continuing health problems and on rare occasions life-threatening consequences.

4. Scientific uncertainties and conflicting opinions

There is ongoing medical and scientific uncertainty and conflicting opinion in relation to many aspects of diagnosis and treatment of Lyme disease. There is a recognised need for further research in order to address core uncertainties and improve patient outcomes.

The symptoms of Lyme disease, whether early or late stage, may be non-specific and easily missed or misdiagnosed. Diagnosis should be clinical, taking into account medical history, signs, symptoms and tick-exposure risk. Since patients may omit to mention a tick bite or unusual skin rash, a detailed clinical history is essential. A travel history is particularly important; there are many regions of Europe and North America where borrelia-infected ticks are highly prevalent. Infection is most likely to occur between late spring and early autumn. (For details see Introduction - epidemiology.)

Lyme serology may be supportive, though a negative test result does not necessarily exclude the diagnosis.

Lyme disease is not notifiable in the UK, however, occupationally acquired cases should be reported via RIDDOR.

Erythema migrans (EM) rash

An EM rash is diagnostic of Lyme disease. However, at least 30% of UK patients may have no rash and may not recall a tick bite. It usually develops within three to 30 days of a tick bite, may not be a typical bull’s eye and may be difficult to differentiate from insect bites. It is not usually hot or itchy and may be distant from the site of the bite. There may be multiple lesions. It may be misdiagnosed as ringworm, cellulitis or other skin conditions and is usually greater than five centimetres in diameter.

In pigmented skin, the erythema may be more difficult to identify. The EM rash may have red, purple or blue hues, or appear as a hyper-pigmented rash.

If uncertain, seek an urgent specialist opinion and consider punch biopsy for molecular (PCR) testing. Avoid any undue delay in initiating treatment.

NICE: Erythema migrans images

CDC: erythema migrans images

Early Lyme disease

This may present with flu-like symptoms ‘out of season’ (with or without an EM rash), for example, fever and sweats, lymphadenopathy, malaise, fatigue, neck pain, migratory myalgia or arthralgia, brain fog, headaches paraesthesia.

It has been documented that borrelia may disseminate through the body at an early stage. Lyme serology may be negative - this does not exclude the diagnosis. Routine blood tests, including inflammatory markers, are usually normal.

Late Lyme Disease

Lyme disease may present with acute or chronic multi-systemic signs and symptoms, weeks, months or even years later, if not diagnosed early. For example:

  • facial palsy
  • meningitis
  • dizziness
  • unexplained radiculopathy
  • encephalitis
  • neuropsychiatric presentations
  • inflammatory arthritis
  • neurological conditions
  • cardiac problems
  • ME/CFS
  • fibromyalgia
  • uveitis or keratitis
  • skin rashes

Diagnosis at this stage may be difficult. Negative serology does not exclude the diagnosis.

Life-threatening and even fatal outcomes such as sudden cardiac arrest and suicide have been reported. These are considered to be rare occurrences, though their true incidence is unknown.

Sudden Cardiac Deaths Associated with Lyme Carditis

Suicide and Lyme disease

Some patients may present with a self-diagnosis of early, late or chronic Lyme disease. These concerns should be investigated appropriately. (In 2017 - only 75% of laboratory confirmed Lyme cases were recorded as ‘acute’.)


Several national and international organisations have produced guidelines:

Paediatric Lyme disease

Children of all ages are potentially at risk. 60% of tick bites on children are above the waist. Ticks can attach in the hairline and on the scalp of children and remain undetected for longer than on adults. Facial palsy with headache and fever has been shown to predict early Lyme disease in children during peak Lyme disease season in endemic areas (May – Oct). In children, anxiety, emotional disorders and difficulties with attention and learning that interfere with school performance may develop if Lyme disease is undetected or untreated.

Imperial College NHS Trust - Lyme disease in children [PDF]

Congenital Lyme disease

The possibility of congenital Lyme disease is a known uncertainty at systematic review level and requires further research. James Lind Alliance's Lyme disease top ten uncertainties.

  • CDC (USA) states: 'Lyme disease acquired during pregnancy may lead to infection of the placenta and possible stillbirth; however, no negative effects on the fetus have been found when the mother receives appropriate antibiotic treatment. There are no reports of Lyme disease transmission from breast milk.'
  • No characteristic pattern of congenital abnormality has been documented in infants of mothers with Lyme disease.
  • It is important to treat a pregnant woman presenting with Lyme disease with antibiotics according to usual practice. Antibiotics such as doxycycline that are contraindicated in pregnancy should be avoided.
  • If a woman contracts Lyme disease during pregnancy, it is advisable to speak to a paediatric infectious disease specialist well in advance of delivery. This will enable consideration to be given to placental and cord blood studies and appropriate follow up of the infant.

Information and advice on testing is available via Public Health England, Health Protection Scotland and NICE.

NB: Testing in early disease may not be reliable.

Start treatment whilst awaiting test results if clinically indicated.

A negative test result does not exclude the diagnosis of Lyme disease.

Details of other relevant tick-borne diseases are listed under ‘Ticks’ in the ‘Key Facts’ section.

Information and advice from Public Health England:

Information and advice from Health Protection Scotland:

NICE: Information and recommendations

Lyme serology tests have diagnostic limitations:

The optimal treatment regimes for EM rashes and disseminated Lyme disease have not yet been determined. Some protocols advocate limited courses of antibiotic treatment. Others consider that persistent symptoms are the result of persistent infection and require individualised treatment regimes. Many doctors and patients report benefit from combined and extended antibiotic treatment regimes.

Tick bites in asymptomatic patients

Prophylactic antibiotic treatment is not routinely recommended. However, there may be some circumstances where specialist opinion would support the idea of a two-week course of antibiotics at treatment level dosages. For example, prolonged tick attachment in a Lyme endemic area, multiple concurrent tick bites, immunosuppression. The evidence for a single dose of doxycycline 200mg is disputed and is not recommended. Patients should be made aware of the signs and symptoms of Lyme disease and advised to seek medical help if required.

Treatment guidelines for Lyme disease

NICE recommends specific antibiotic regimes for adults and children. The guideline committee acknowledged the limited evidence upon which their recommendations were based and made research recommendations.

Jarisch-Herxheimer reaction

Be aware of the possibility of a Jarisch-Herxheimer reaction. This is a systemic reaction thought to be caused by the release of cytokines when antibiotics kill large numbers of bacteria. Symptoms may include a worsening of fever, chills, muscle pains and headache. The reaction may start soon after starting antibiotics but can also occur slightly later and may last for a few hours or several days. It is self-limiting and resolves spontaneously.

Persistent symptoms

There is no international consensus on the cause and management of persistent symptoms. Possible explanations for persistent symptoms following a diagnosis of Lyme disease include:

  • treatment failure
  • immune dysfunction
  • non-adherence
  • re-infection
  • tissue damage

This is variously described as either Post-Treatment Lyme Disease Syndrome (PTLDS), Post-Treatment Lyme Disease (PTLD) or Chronic Lyme disease.

Post-Treatment Lyme Disease Syndrome

This implies a post-infectious state. A supportive ‘wait and see’ policy is suggested.

Post-Treatment Lyme Disease

This is a more descriptive term which acknowledges the possibility of ongoing infection as well as immune dysfunction and tissue damage as a cause for continuing symptoms.

Chronic Lyme disease

This is an ill-defined term which encompasses a range of concepts.

Many doctors and researchers consider that the ongoing symptoms may be driven by chronic infection. For example, borrelia, another tick-borne infection, an opportunistic infection or other factors. These doctors advocate the use of individualised treatment regimes. Many patients report significant improvement after treatment with extended treatment regimes and or complementary therapies, although others do not.

Researchers at Johns Hopkins Lyme Disease Research Centre have identified Post Treatment Lyme Disease (PTLD) as ‘a serious and impairing condition’, affecting a ‘subset of patients who remain significantly ill 6 months or more following standard antibiotic therapy for Lyme disease’. Risk factors for developing PTLD appear to include delay in diagnosis, increased severity of initial illness and the presence of neurological symptoms. Research into the causes and management of this condition is ongoing

Alternative diagnoses

The possibility of alternative diagnoses must be fully evaluated, for example:

  • anaemia
  • hypothyroidism
  • B12 deficiency
  • Vitamin D deficiency
  • neurological, rheumatological or cardiac conditions
  • GI disorders
  • psychiatric or psychological disorders
  • malignancy
  • ME/CFS
  • fibromyalgia
  • postural orthostatic tachycardia syndrome
  • other multi-systemic illnesses such as SLE or Ehlers-Danlos syndrome

The following resources provide information on other conditions that may present as Lyme disease:

  • There are significant uncertainties surrounding the epidemiology of Lyme disease in the UK, and its diagnosis and treatment.
  • There has been a general lack of funding for Lyme disease research in Europe and the USA compared to other infectious diseases. The NICE guideline process found that very few published studies on Lyme disease met criteria for inclusion in the guideline, and most which were included were of low and very low quality.
  • Research into Lyme disease is challenging. Lack of consistent case definitions and gold standard diagnostic tests, limited outcome measures and difficulty studying the disease process in humans are factors. Division of expert opinion leading to controversy rather than debate has hampered progress.
  • The top 10 uncertainties about diagnosis and treatment of Lyme disease in the UK, were published in 2012 via a James Lind Alliance Priority Setting Partnership commissioned by Lyme Disease Action.
The NICE Clinical Guideline for Lyme disease (NICE NG95) noted that there were still a number of scientific uncertainties:
  • The nature of persistent symptoms following treatment, and whether this may be due to persistent infection, post-infectious immune dysfunction or tissue damage.
  • A better understanding of the human immune response to Borrelia in early and late-stage infections, including variability between individuals.
  • The potential risk of other means of Lyme disease transmission such as congenital, sexual, via blood transfusion or organ donation.
Current scientific research is seeking to explore core issues such as:
  • Whether the bacteria may survive antibiotic treatment and cause persistent infection.
  • How the bacteria interact with the host immune system to survive immune clearance.
  • The production of a safe and effective vaccine for Lyme disease.

A 2021 review paper, co-authored by a members of the research community provides ‘a detailed summary of progress over the past 5 years in understanding of Lyme and tick-borne diseases in the United States and highlights remaining challenges.’

Educational and training material for clinicians

Defence Primary Health Care

Military personnel are at increased risk of exposure to tick-borne infections both within the UK and whilst deployed overseas. Confirmed or suspected cases of Lyme disease should be reported via RIDDOR:

Educational material for the waiting room

RCGP podcast: Introduction to Lyme disease

There's a need to increase public awareness of tick-bite prevention measures, appropriate tick removal methods and the symptoms of Lyme disease.

Government and NHS web sites providing useful information on ticks and Lyme disease:

Other organisations providing information on ticks and Lyme disease:

Forestry Commission Scotland has produced a series of educational videos.

Veterinary advice

Pet owners are one and a half times more likely to be bitten by a tick than non-pet owners. This risk extends beyond rural areas.

Where to check your pet for ticks image

Information for travellers

Incidence and surveillance of Lyme disease in the UK

Estimates of the health and social costs of Lyme disease

The true incidence of Lyme disease in the UK is unknown, but appears to be increasing. The total number of laboratory confirmed cases for England and Wales was 1,579 in 2017. The estimated number of cases per year is thought to be at least 3,000, though may be very much higher. European research has shown that a significant number of patients who are diagnosed with neurological Lyme disease, particularly if diagnosed at a late stage, develop long term health problems. The subsequent health and social care costs for these patients may be considerable.

There are no UK wide data on the financial implications of Lyme disease. However, in 2003 the total annual cost for Scotland, was estimated to be significant at £331,000 (range £47,000 – £615,000).

In 2017, an estimate of the annual societal costs of Lyme disease in the Netherlands was calculated at 20 million euros for an annual incidence of 25,000 cases of Lyme disease.

Assuming similar health and social care costs, an annual incidence of around 4,000 to 5,000 cases could result in a societal cost of between £3 million - £3.5 million per year.

Early diagnosis and treatment of Lyme disease provides the best chance of cure. There are possible financial benefits that NHS managers and commissioners should consider by raising awareness in public and primary care.

This toolkit was developed by the RCGP Lyme disease Spotlight Project team.

Please send any comments or suggestions to