A patient was diagnosed (through blood tests) with Lyme Disease after a tick bite and treated with first oral and then intravenous antibiotics, apparently successfully. The patient saw the physician the day after the rash appeared; diagnosis took about a week. The date of the bite was not known; the patient never saw the tick. Treatment started with oral antibiotics but symptoms (joint pain, primarily) remained and the physician followed with a month-long course of IV antibiotics. I do not know which specific drugs were used. Total time from first visit to the end of the IV treatment was about five months.

At the time the patient was told by the physician that the blood test for Lyme looks for antibodies, which would "always be there now", which is why it was not possible to say with certainty that the disease had been treated. The patient was also told that the characteristic bull's-eye rash only appears in about 25% of cases. Years have passed since this happened.

If this patient were to be bitten by another tick in the future, would it be possible to make a determination of Lyme Disease? If so, how?

(The patient takes appropriate precautions but knows that nothing is ever 100% effective.)

  • 1
    @Monica - The rash is present in more like 50%, with lots of documentation for 85%. 25% is too low an estimate, even for those of us who believe that the disease occurs far more frequently than recognized. Aug 17, 2015 at 4:26
  • @anongoodnurse thanks for the information -- good to know. Aug 17, 2015 at 13:09

1 Answer 1


Patients successfully treated for Lyme Disease do not need monitoring of any kind (there is no advantage to this.) There are no recommendations for routine antibody levels post Lyme (in fact, it is discouraged, because no one knows what the levels signify), nor yearly exams or other.

It is the responsibility of the patient (and the patient should be so instructed) to return if they are having continuing or new problems.

A bit of background:

The diagnosis and (standard) treatment of Lyme should be swift and proactive, not reliant on positive antibodies. The possibility of Lyme should be present in a physician's mind when seeing a patient with typical signs and symptoms (and should be treated before any confirmatory testing is completed), as well as any illness which presents a diagnostic challenge. Unfortunately should doesn't always translate to is.

Antibody test results generally are not useful for the diagnosis of early Lyme disease because only a few patients with single EM [erythema migrans] will have a positive result because the rash usually develops before antibodies are detectable. The antibody test result is often negative in the acute phase even in those with multiple EM. Even in the convalescent phase after antimicrobial treatment, antibody test results are negative in approximately half of those with single EM and a quarter of those with multiple EM.

This is an interesting question on a lot of levels, some of the answers to which are still being worked out.

Typically when a person is first exposed to a pathogen, the early antibodies made are of the IgM class, followed temporally by IgG. IgM should not be made on re-exposure, but re-exposure should kick up the level of IgG. However, Borrelia burgdorferi infections are not typical.

In people treated early for Lyme, often IgG never develops. IgM, on the other hand, can persist for two decades or more (studies are still ongoing) as well as IgG in those who formed these antibodies. IgM, therefore, is not as predictive of initial infection as in other infections. Antibodies can't be relied upon to make a diagnosis.

Many patients who receive early and appropriate treatment for Lyme disease continue to live in or frequent regions where ticks are endemic, therefore repeated tick bites are quite common.

In 1 study of persons from New York with recently recognized Ixodes scapularis tick bites, 59 (17.6%) of 335 subjects reported new tick bites during a 6-week follow-up period...

This was 6 weeks! In one study, the reinfection (not to be confused with continuing symptoms following treatment) rate within the 5 years following initial successful treatment was ~50%.

Reinfection is usually accompanied by recurrence of EM and/or the fever, myalgia, and arthralgia common with initial Lyme Disease, though there is some (not strong) evidence that symptoms may be less severe on reinfection. So suspicion should remain high in people who live in endemic areas, of those counties near to endemic areas because of the spreading of the bacterium, time of year (most new infections occur in July, June, August and May, in descending order; there's no reason to suspect reinfection is any different), etc.

In the foreseealbe future, there will be tests to determine the presence of bacterial DNA in joint fluid, tissue samples and other, which will help in the diagnosis of the illness, success of treatment, and reinfection. But medicine isn't quite there yet.

Edited to add:

If this patient were to be bitten by another tick in the future, would it be possible to make a determination of Lyme Disease? If so, how?

No, it wouldn't be possible to test for the diagnosis. If a person in an endemic area presents with a tick bite in which the tick was starting to become engorged, a single 200mg dose of doxycycline has been shown to effectively prevent 80+% of new infections, so that's always an option (one I'm not quite sure of.) If the patient goes on to develop the rash or flu0like symptoms, a full course of antibiotics is then given.

TL;DR: There are insufficient studies about the immunology of reinfection. The diagnosis and treatment will depend on the discernment of the patient + physician. If the person is in an area with high infection rates, the index of suspicion and willingness to treat should be high.

  • Lyme disease is diagnosed based on symptoms, physical findings (e.g., rash), and the possibility of exposure to infected ticks.
  • Current diagnostics are less than optimal for early disease because it can take weeks for a detectable immune response to be sufficiently measured. So the early stages of disease which when treatment is typically most effective unfortunately are when serum diagnostics are least effective. - CDC Webinar Sept 2012

Borrelia burgdorferi (Lyme Disease) <-- decent overview with some mistakes
Persistence of Immunoglobulin M or Immunoglobulin G Antibody Responses to Borrelia burgdorferi 10–20 Years after Active Lyme Disease
Antibiotic Treatment Duration and Long-Term Outcomes of Patients with Early Lyme Disease from a Lyme Disease–Hyperendemic Area
Reinfection in Patients with Lyme Disease
some statistics (not all up to date but still helpful)
more statistics

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    Good answer. Let´s not get into "chronic borreliosis" :). In the foreseealbe future, there will be tests to determine the presence of bacterial DNA in joint fluid In my workplace our lab can perform a PCR of a joint fluid sample. Last time we did this was a patient with atypical arthritis, it was suspected to be bacterial and thus PCR was done. Just to be sure, are you referring here for burgdorferi bacteria only or bacterial DNA in general?
    – arkiaamu
    Aug 18, 2015 at 16:56
  • @arkiaamu - B. burgdorferi; it wouldn't be much help if it were just bacteria in general. ;-) Aug 18, 2015 at 18:24
  • "a single 200mg dose of doxycycline has been shown to effectively prevent 80+% of new infections" I've heard differently. Do you have a source for this? (Thank you :)
    – Jess
    Jul 3, 2019 at 17:40
  • @Jess - the CDC Jul 4, 2019 at 2:48

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