What is Lyme disease and how is it diagnosed and treated?

Close-up of a hiker using a tick removal tool to remove an embedded tick

Lyme disease is a bacterial infection that can be transmitted to humans through the bite of infected ticks, usually outdoors in green spaces. It is most commonly reported in the south of England and London, although cases are seen across the country. You can reduce your chance of infection by following sensible precautions.

To help you stay safe, this post explains what Lyme disease is, how to recognise the signs and symptoms, and when to seek medical assistance.

What are the symptoms of Lyme disease?

Symptoms may include:

a spreading ‘bullseye’ rash (erythema migrans) at the site of the tick bite is the most common symptom and typically occurs between 3 and 30 days of being bitten, Although it is the most common symptom, a bullseye rash does not occur in all cases mild flu-like symptoms such as fever, headache and fatigue a facial droop nerve pains numbness or tingling in the hands or feet

In rare cases:

palpitations joint swelling

You can see images of the ‘bullseye’ rash on the NHS website. Rapid recognition of symptoms can ensure that you receive the earliest diagnosis and treatment.

What should I do if I have symptoms of Lyme disease?

If you become unwell within a few weeks of being bitten by a tick, contact your GP practice or dial NHS 111 promptly. Not everyone will realise that they were bitten by a tick, so you may still develop Lyme disease symptoms without remembering a tick bite. There are national guidelines for doctors providing advice on diagnosis and management of Lyme disease.

Can Lyme disease be treated?

In the UK, Lyme disease is an uncommon infection and can be successfully treated with antibiotics as per National Institute for Health and Care Excellence (NICE) guidelines. Most patients treated in the later stages of infection also respond very well to antibiotics, although some may have long-term damage to their joints or the nervous system.

What is 'chronic Lyme disease'?

Although most people with Lyme disease recover from the infection quickly and completely, it is not unusual to feel some lingering fatigue or muscle pain at the time you finish your course of antibiotics. These symptoms generally resolve on their own over time, although for 10 to 20% of people they can persist for more than 6 months. 

Symptoms that persist for 6 months or more after treatment for Lyme disease following a bullseye rash or a reliable laboratory diagnosis, are known as Post-Treatment Lyme Disease Syndrome (PTLDS). The persistent symptoms are not due to ongoing infection, and further antibiotics are not effective.

The term 'chronic Lyme disease' is sometimes used for patients who have several subjective, unlinked symptoms without any documented evidence of Lyme disease on approved tests. The term ‘chronic Lyme disease’ is misleading and may lead to unnecessary treatments including prolonged antibiotics.

Ongoing symptoms after an infection are not unique to Lyme disease and can occur after many infections such as glandular fever or pneumonia.

Should I get tested by the NHS or a privately funded laboratory?

If you have a classic bullseye rash, you should be treated for Lyme disease without the need for a test. If you have a recent tick exposure and symptoms of Lyme disease but no bullseye rash, guidance to NHS doctors in England is to take a blood sample and send it for testing at an NHS or UKHSA laboratory.

The tests work by looking for antibodies against the bacteria that cause Lyme disease. The antibodies take some time to reach detectable levels, so tests carried out early on in infection might be negative and may need to be repeated on a fresh blood sample taken 4 to 6 weeks after the first test.

We recommend people exercise caution with private tests and speak to their NHS doctor for advice before spending money on private tests or treatments, as some private laboratories and clinics offer unreliable tests and treatments that are not supported by the scientific community. Diagnostic tests done outside the NHS are sometimes not specific enough, so patients may be more likely to receive a wrong diagnosis of Lyme disease. Our advice is to seek help through the NHS.

Are cases of Lyme disease increasing?

A UKHSA annual report published in May 2026 confirmed that Lyme disease remains the most common locally acquired vector-borne infection in England.

There are between 1,000 to 1,500 laboratory-confirmed cases of Lyme disease in England and Wales each year. Many cases are diagnosed in the community - for instance due to the presence of a bullseye rash - without needing laboratory testing, so the exact total number of cases in the UK is not known. UKHSA is working to better estimate the full number of cases in the community.

Laboratory-confirmed case numbers have risen in the UK since records began, likely due to a combination of increased awareness among the public and healthcare professionals, improved surveillance, changes in the distribution of ticks, and ticks being active for longer periods due to a warming climate. Since 2018, this increase has not been sustained year-on-year and laboratory cases have stabilised with some annual fluctuations.

A large study of blood donors in England estimated that around 0.5% of the population have antibodies to the bacteria that causes Lyme disease - a figure lower than in Scotland and many mainland European countries.

What is UKHSA's role in handling Lyme disease?

We monitor the risks to public health of infections like Lyme disease and the vectors (living organisms that transmit disease) that carry them. Our work includes surveillance, horizon scanning and risk assessments. Our Centre for Climate and Health Security collates and translates complex data on tick populations into guidance for preparedness and response to vector-borne diseases including Lyme disease.

As of 2026, UKHSA is producing One Health Vector-Borne Disease annual surveillance reports that provide data on the geographical presence and distribution of disease-transmitting vectors and vector-borne diseases, monitoring changes over time to inform assessments of risks to public health.

https://ukhsa.blog.gov.uk/2026/06/30/what-is-lyme-disease-and-how-is-it-diagnosed-and-treated/

seen at 10:35, 30 June in UK Health Security Agency.