Lyme disease: symptoms, diagnosis, treatment and what to watch for after a tick bite

What is Lyme disease?

Lyme disease is a bacterial infection transmitted by the bite of an infected tick. It is caused by bacteria of the genus Borrelia. Ticks can acquire the bacteria when feeding on infected animals and subsequently transmit them to people.

Early signs may include an expanding skin rash, fatigue, headache, fever, or muscle and joint pain. The rash does not always look like a bull’s-eye and is not noticed in every case. Nonspecific symptoms alone do not establish the diagnosis.

Lyme disease does not spread through ordinary contact between people, such as shaking hands, coughing, hugging or sharing objects. Isolation is not needed. In some people, untreated infection can later affect the nervous system, heart, joints or skin.

What does erythema migrans look like?

Erythema migrans is an expanding area of skin redness that usually appears days to weeks after infection. It may be uniformly red or have a paler centre. It is not necessarily painful or itchy and does not always form a bull’s-eye pattern.

A small area of redness immediately after tick removal may be a local skin reaction. Such irritation usually does not expand and gradually resolves. Show an expanding rash to a clinician.

Typical erythema migrans is diagnosed clinically. Treatment should not be delayed while waiting for a blood test.

Early symptoms

Alongside skin changes, symptoms may include fatigue, headache, raised temperature, chills, muscle or joint pain, swollen lymph nodes and general weakness. These can resemble a viral illness.

These symptoms are not specific to Lyme disease. A history of a tick bite, time outdoors and the development of any skin changes helps the clinical assessment.

Neuroborreliosis: effects on the nervous system

Neurological manifestations may appear weeks to months later. They can include facial nerve palsy, a drooping mouth, shooting nerve pain, tingling or altered sensation, severe headache, neck stiffness and weakness.

Sudden facial drooping, speech difficulties, weakness on one side of the body or sudden changes in vision can also indicate a stroke. Seek immediate medical help; do not wait for a Lyme disease diagnosis.

Can Lyme disease affect the heart?

Lyme carditis is a less common complication in which the infection can affect the heart’s electrical conduction. Possible symptoms include palpitations, an irregular pulse, dizziness, fainting, shortness of breath, chest pain or pressure and unusual weakness.

Fainting, chest pain, severe breathlessness or a serious disturbance of the pulse requires urgent medical assessment.

Lyme arthritis: joint swelling

Lyme arthritis can occur later in the disease. It commonly affects a large joint, particularly the knee. Marked swelling, tightness and limited movement may occur, with episodes that recur or persist. Pain may sometimes be less severe than the swelling suggests.

A swollen knee does not automatically mean Lyme disease. Injury, gout, autoimmune disease and bacterial joint infection are other possible causes.

Diagnosis and blood tests

Clinicians assess symptoms, skin findings, possible tick exposure and laboratory results. A neurological examination or other organ-specific tests may be needed. The diagnosis does not rest on a single laboratory result.

Blood tests detect antibodies against Borrelia bacteria. These take time to develop, so an early negative test does not completely rule out infection. Typical erythema migrans is diagnosed from the clinical findings.

Positive antibodies alone do not confirm an active infection. They can remain detectable for months to years after a previous infection. Results must be interpreted alongside symptoms and examination findings.

How is Lyme disease treated?

Lyme disease is treated with antibiotics. Depending on the manifestation, age and health status, options include doxycycline, amoxicillin or cefuroxime. Some manifestations require intravenous treatment. The clinician selects the medicine, dose and treatment duration.

More antibiotics do not automatically mean better treatment. Prolonged or repeated courses without evidence of active infection can cause adverse effects and are not the usual standard of care for persistent nonspecific symptoms.

What if symptoms persist after treatment?

Some people experience fatigue, pain or cognitive difficulties for a time after appropriate treatment. These symptoms do not automatically prove that living Borrelia bacteria remain in the body.

Persistent symptoms warrant an assessment of overall health and consideration of other possible causes.

What to do after a tick bite

Remove an attached tick as soon as possible. With fine-tipped tweezers, grasp it as close to the skin as possible and pull straight upwards with steady pressure. Do not twist or jerk. Clean the bite area, wash your hands and record the date and location of the bite. Monitor your skin and health over the following weeks.

Do not coat the tick with oil or cream or burn it. The risk of transmission increases with the duration of attachment, so avoid unnecessary delays.

Does everyone need antibiotics after a tick bite?

No. Preventive antibiotics are not automatically given after every tick bite. In certain situations, a clinician may consider prophylaxis based on the specific risk, local guidance and time since tick removal.

Do not take antibiotics on your own “just in case”.

Prevention and when to seek medical advice

Wear appropriate clothing, closed shoes and long trousers outdoors. Use repellent according to its instructions. After returning, check your entire body, including the armpits, groin, behind the knees, scalp and behind the ears. Check children and pets too. Remove any attached tick promptly.

Seek medical assessment for an expanding rash, new facial palsy, unexplained nerve pain, marked swelling of a large joint, palpitations, an irregular pulse or symptoms that persist or worsen after a tick bite.

Seek immediate medical help for sudden neurological symptoms, fainting, chest pain, severe breathlessness or rapidly developing painful joint swelling.

Frequently asked questions

Professional sources

• ECDC: Lyme borreliosis factsheet
• ECDC: Factsheet for healthcare professionals
• CDC: Signs and symptoms
• CDC: Testing and diagnosis
• CDC: Chronic symptoms after treatment
• NICE NG95: Recommendations
• CDC: After a tick bite

Author: Ing. František Kokoš · Updated: 12. 10. 2026