Lyme Disease: Diagnosis and Treatment


Lyme disease is a serious condition caused by spirochetal bacteria Borrelia burgdorferi sensu lato following a deer tick bite that requires treatment.  The following provides key points regarding diagnosis, treatment, prophylaxis and tick removal.


Early features (3 to 30 days after tick bite) to watch for include:

  • Erythema migrans
    • 70 to 80% of infected individuals
    • At site of tick bite approximately day 7 (range 3 to 30 days)
  • Fever, headache, and fatigue
  • Joint and muscle aches
  • Swollen lymph nodes

Late features (days to months after tick bite)

    • Severe headaches and neck stiffness
    • Additional Erythema migrans rashes on other areas of the body
    • Arthritis with severe joint pain and swelling, particularly the knees and other large joints
    • Facial palsy (cranial neuritis)
    • Intermittent pain in tendons, muscles, joints, and bones
    • Heart palpitations or an irregular heart beat (Lyme carditis)
    • Episodes of dizziness or shortness of breath
    • Lyme meningitis or encephalitis
    • Nerve pain (radiculoneuritis)
  • Problems with short-term memory


Note: The CDC has updated the Lyme laboratory screening algorithm

  • CDC still recommends the two step approach
    • Step 1: Serologic testing using a sensitive enzyme immunoassay (EIA) or immunofluorescence assay
    • Step 2: Follow step one with a western immunoblot assay for specimens yielding positive or equivocal results
  • Modified two-step approach
    • Two enzyme immunoassays (EIA) are run concurrently or sequentially
    • The CDC states that

When cleared by FDA for this purpose, serologic assays that utilize a second EIA in place of western immunoblot assay are acceptable alternatives for the serologic diagnosis of Lyme disease


  • Two-tiered serologic testing is more sensitive the longer infection has been present
  • Myth that Lyme disease can become chronic and no longer detectable on lab testing


  • First line therapy for adults with early localized or early disseminated Lyme disease associated with erythema migrans, in the absence of specific neurologic manifestations or advanced atrioventricular heart block:
    • Doxycycline: 100 mg twice per day for 14 days (range 10 – 21 days), or
    • Amoxicillin: 500 mg 3 times per day for 14 days (range 14 – 21 days), or
    • Cefuroxime axetil (500 mg twice per day) for 14 days (range 14 – 21 days)
  • For treatment of late Lyme disease including arthritis, the above regimen is advised for 28 days
  • For persistent symptoms, such as joint swelling, Lyme meningitis, Lyme carditis, and dosing for children, see IDSA guidance in “Learn More – Primary Sources” below
  • The CDC concurs with the following IDSA recommendation that advises strongly against the treatment of chronic Lyme disease (highest level of evidence ‘I’, based on randomized controlled trials) as overtreatment with unnecessary antibiotics may prove fatal (e.g. septic shock, C. difficile, paraspinal abscess and osteomyelitis):

There is no convincing biologic evidence for the existence of symptomatic chronic B. burgdorferi infection among patients after receipt of recommended treatment regimens for Lyme disease. Antibiotic therapy has not proven to be useful and is not recommended for patients with chronic (⩾6 months) subjective symptoms after recommended treatment regimens for Lyme disease.

Prophylaxis: Management of asymptomatic individuals following a tick bite

  • Routine use of antimicrobial prophylaxis or serologic testing is not recommended
  • A single dose of doxycycline may be offered to adult patients (200 mg dose) and to children ⩾8 years of age (4.4 mg/kg, up to a maximum dose of 200 mg) when all of the following are met:
    •  The attached tick can be reliably identified as an adult or nymphal I. scapularis deer tick that is estimated to have been attached for ⩾36 h on the basis of the degree of engorgement of the tick with blood or on certainty about the time of exposure to the tick
    • Prophylaxis can be started within 72 h of the time that the tick was removed
    • Ecologic information indicates that the local rate of infection of these ticks with B. burgdorferi is ⩾20% (generally occurs in parts of New England, in parts of the mid-Atlantic States, and in parts of Minnesota and Wisconsin)
    • Doxycycline is not contraindicated

Tick Removal

  • The risk of getting a tick-borne disease is small if the tick is removed soon after it becomes attached
    • Deer ticks must remain attached one to two days to transmit Lyme disease, and about one day for the other diseases
  • Use tweezers to grasp the tick close to its mouth
  • Gently and slowly pull the tick straight outward
  • To avoid contact with the bacteria, if present, do not squeeze the ticks’ body
  • Wash the area and apply an antiseptic to the bite
  • Watch for early signs and symptoms of Lyme disease

Lyme Disease and Pregnancy

  • The CDC 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.

Note: Treatment in pregnancy is similar to that of nonpregnant adults, although certain antibiotics, such as doxycycline, should be avoided due to potential risk related to dental discoloration that is associated with the tetracycline class of drugs

Learn More – Primary Sources:

CDC MMWR: Serious Bacterial Infections Acquired During Treatment of Patients Given a Diagnosis of Chronic Lyme Disease — United States 

CDC: Lyme Disease Diagnosis, Treatment and Testing

Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR): 2020 Guidelines for the Prevention, Diagnosis and Treatment of Lyme Disease

Signs and Symptoms of Untreated Lyme Disease

Minnesota Department of Natural Resources: Deer Ticks

CDC: Lyme Disease Transmission

JAMA: Lyme Disease in 2018 – What Is New (and What Is Not)

FDA clears new indications for existing Lyme disease tests that may help streamline diagnoses

CDC: Updated CDC Recommendation for Serologic Diagnosis of Lyme Disease

BMJ State-of-the-Art Review: Lyme borreliosis: diagnosis and management