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lyme disease

Lyme disease, also known as Lyme borreliosis, is an infection caused by a spiral shaped bacteria (spirochaete) called Borrelia, which can be passed to humans by the bite of an infected tick.

It is the most common tick borne infection in Europe and the USA. Its name comes from the town of Old Lyme in Connecticut, USA, although its symptoms and clinical picture were first recognised in Europe in the 1800s.

Lyme disease is treatable with antibiotics. However, if the diagnosis and treatment are delayed or missed then it can potentially cause long term health problems. UK population studies indicate that the incidence is increasing and likely to be higher than official estimates. (Incidence of Lyme disease in the UK:  BMJ Open)

Signs and symptoms of Lyme disease

Early Lyme disease

Symptoms of early Lyme disease usually appear within days or weeks of a tick bite. Though they can appear up to 3 months after the bite. These include an erythema migrans(EM) rash and flu-like symptoms (out of season). 

Erythema Migrans (EM) Rash

  • An EM (bull’s eye) rash is diagnostic of Lyme disease but may not be present, or may go unnoticed in at least 30% of cases. It usually develops within 3-30 days of a tick bite.

  • If an EM rash is present then treatment with antibiotics should be started as soon as possible. A blood test is not required to confirm the diagnosis.

  • The EM rash may look like an area of uniform redness rather than a ‘bull’s eye’; it is usually painless and not itchy and typically greater than 5cm in diameter.

  • It will usually appear at the site of the bite, though not always. Multiple EM rashes sometimes appear on other areas of the body.

  • Some EM rashes are very faint and difficult to see, and may look different in  pigmented skin compared to the photos in textbooks. The rash may become more obvious after a bath or shower. 

  • You should take photos of the rash ( and share with your GP).

  • An EM rash may disappear spontaneously without antibiotic treatment. However, this does not mean the infection itself has resolved. A course of antibiotics is still required. If left untreated the disease may spread around the body.

  • A small (less than 2cm) localised area of redness may occur in response to a tick bite but this usually resolves in 3-5 days and is probably not necessarily an indication of Lyme disease.

  • An EM rash may be misdiagnosed as ringworm, another insect bite or a skin infection - particularly if the patient does not recall a previous tick bite.




Erythema migrans (Source:​​​​

Flu-like symptoms

These may be mild or severe and may be misdiagnosed as a viral infection or ‘summer-flu’. Symptoms may occur with or without an EM rash and may include:

·  fatigue

·  neck pain

·  joint pain

·  muscle pain

.  headaches

·  fevers and sweats

·  neurological problems like brain fog or poor concentration


The possibility of Lyme disease may be underestimated if clinicians fail to consider, or patients forget to mention, the possibility of a tick bite or tick exposure.  A negative blood test result does not exclude the diagnosis.  The NICE Guideline advises starting treatment if there is a high clinical suspicion of Lyme disease. 

Lyme disease | Guidance | NICE


In some cases, the infection spreads around the body at an early stage (within weeks to  months of an infected tick bite) causing  more specific symptoms such as facial palsy and cardiac symptoms.

High frequency of paediatric facial nerve palsy due to Lyme disease in a geographically endemic region - ScienceDirect 

Late stage Lyme disease

If the early symptoms of Lyme disease are missed, misdiagnosed or inadequately treated then the infection may spread to infect multiple areas within the body such as the nervous system, joints, skin, heart and eyes. This may occur weeks, months or years after the initial infection - when the original tick bite or infection may be long forgotten. Diagnosis at this stage may be difficult. In some cases, symptoms may come and go and migrate around the body.

A negative blood test result does not necessarily rule out a diagnosis of Lyme disease.

Recommendations | Lyme disease | Guidance | NICE


Neurological symptoms:

  • Facial palsy, unexplained nerve pain, weakness, tremor, dizziness

  • Unexplained neurological symptoms - sometimes misdiagnosed as other conditions

  • Headaches

  • Encephalitis

  • Meningitis

  • Dysautonomia ( dysfunction of the autonomic nervous system)

LDA leaflet on neuroborreliosis lymediseaseaction


Neuropsychiatric symptoms:

  • Anxiety

  • Depression

  • Altered cognitive function -  poor concentration, difficulty with numeracy and word finding

  • Brain fog

  • Fatigue

Musculoskeletal symptoms:

  • Inflammation in joints, muscles and tendons - often comes and goes and migrates around the body.

  • Fibromyalgia

Dermatological symptoms:

  • Recurrent EM rashes

  • Lymphocytoma - a  painless bluish-red nodule which can occur on the ear lobe in children

  • Acrodermatitis chronica atrophicans (ACA)



Cardiac conditions:

  • Inflammation of the heart - myocarditis, pericarditis

  • Arrhythmias ( irregular heart beat )

  • Sudden cardiac death has sometimes been reported

Eye conditions:

Diagnosing and Testing for Lyme disease

In many cases the diagnosis may need to be based upon clinical symptoms alone. Laboratory investigations may help to support the diagnosis.

The NICE Guideline on Lyme disease includes the following statements:

  • Diagnose and treat Lyme disease without laboratory testing in people with erythema migrans.

  • Use a combination of clinical presentation and laboratory testing to guide diagnosis and treatment in people without erythema migrans.

  • Do not rule out diagnosis if tests are negative but there is high clinical suspicion of Lyme disease.

  • If there is a clinical suspicion of Lyme disease in people without erythema migrans:

    1)Offer an ELISA test for Lyme disease and
    2)Consider starting treatment with antibiotics while waiting for the results if  there is a high clinical suspicion         

The blood test for Lyme disease ( ELISA)  looks for antibodies to the bacteria that cause Lyme disease, but not the bacteria itself. If the test is done at an early stage in the disease, or the patient has a suppressed immune system, then antibodies may not have developed sufficiently and the test may be negative despite active infection. Antibodies can sometimes persist for years  even after a patient has been treated and has no active disease. Both false-negative and false-positive results can occur.

Recommendations | Lyme disease  NICE 

Treating Lyme disease

If Lyme disease is diagnosed or suspected then antibiotic treatment should be started a soon as possible. Type and dosage of antibiotic will depend on the age of the patient and the severity of the infection. The dosages used are higher than for many other infections and should  usually continue for at least 3 weeks.

NICE has developed a treatment protocol: Recommendations | Lyme disease  NICE

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. Research is ongoing.


Jarisch-Herxheimer reaction
This is a reaction that can occur within the first few days of starting antibiotics for Lyme disease. Symptoms may include a worsening of fever, chills, muscle pains and headache. The reaction may last for a few hours or several days. It is usually self-limiting and resolves spontaneously.

Persistent symptoms after treatment

Many patients report ongoing symptoms following treatment for Lyme disease. In many cases these symptoms resolve over time, but others (around 10-20% of cases) report persistent, often severe symptoms. These are often referred to as either Post Treatment Lyme disease (PTLD) or chronic Lyme. There is no international consensus on the causes or management of these symptoms, research is ongoing into these genuine scientific uncertainties. 

Lyme Disease Treatment | Prognosis for Lyme Patients after Treatment

Advice for patients who suspect they have or may have Lyme disease

1) Seek medical advice as soon as possible if you notice a rash or feel unwell following a tick bite or tick exposure.  Be sure to mention your concerns, including any recent travel.

2) Remember that ticks may be present in parks and gardens as well as rural and wooded areas. Tick bites are painless and may go unnoticed.

3) Take (and keep) clear photos of the rash

4) An erythema migrans rash may be ‘atypical’ and not necessarily a bull’s eye appearance. It can be uniform in colour, and may have hues of pink, purple, red, or blue or deepening of the existing skin tone. It is diagnostic for Lyme disease and must be treated, without the need for a blood test.

5) If your health professional seems unsure about the diagnosis and treatment of Lyme disease then ask them to view the Royal College of GPs (RCGP) Lyme disease Toolkit which includes the NICE Guideline on Lyme disease.  
Lyme disease toolkit

6) If symptoms persist after three weeks of antibiotics then a second course of treatment may be required. Recommendations | Lyme disease| NICE

7) Remember:

  • 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.

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

Image by Erik Karits
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