Single dose doxycycline for treatment of tick bite only prevents Lyme disease rash

Man taking doxycycline which will only prevent Lyme disease rash.

In a review entitled “Lyme Disease: Emergency Department Considerations,” Applegren et al. recommend using a one-time, single dose of doxycycline for the prophylactic treatment of a tick bite, [1] despite the fact that there has been only one study exploring the effectiveness of such a limited dosage. The article also neglects to mention that there are doctors who take a different approach and advise against a one-time, single dose. [3]

In the article, the authors reference the 2006 Infectious Diseases Society of America (IDSA) guidelines when making their recommendation that “individuals be treated with a single dose of doxycycline (4 mg/kg in children ≥8 years of age to a maximum 200 mg and 200 mg in adults)”. [1]

Their recommendation applies only to patients meeting the following criteria, “(1) the attached tick is clearly identified as a nymph or adult I. scapularis; (2) the tick has been attached ≥36 hours; (3) local infection rates of ticks with B. burgdorferi is ≥20%; and (4) there are no contraindications to doxycycline.” [2]

The authors fail to mention that the IDSA single dose of doxycycline approach is based on one study, which only found a reduction in the number of erythema migrans (EM) rashes.

“A study by Nadelman et al. found that patients treated with a single dose of doxycycline developed EM manifestation at a lower rate than the placebo group (0.4% compared to 3.2%, respectively),” according to Applegren. 

The review also does not mention the evidence, as put forth by the International Lyme and Associated Diseases Society (ILADS), which finds that a single dose is ineffective in warding off Lyme disease. Such evidence was easily accessible via open access, peer-reviewed journals in PubMed [3], the Journal’s website[4], and the National Guideline Clearing House. [5]

ILADS 2014 guidelines used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to conclude that the evidence for a single, 200 mg dose of doxycycline was “sparse, coming from a single study with few events, and, thus, imprecise.” [3]

There were only 9 EM rashes in the Nadelman study. Nadelman and colleagues were able to reduce the number of rashes from eight to one by prescribing a single 200 mg dose of doxycycline. The “p” value was barely significant at 0.04.

The IDSA guidelines adopted the single, 200 mg dose of doxycycline despite the fact that 3 previous prophylactic antibiotic trials for a tick bite had failed.

Nadelman’s study had several other limitations:

  1. It was not designed to detect Lyme disease if the rash were absent.
  2. The 6-week observation period was not designed to detect chronic or late manifestations of Lyme disease.
  3. It was not designed to assess whether a single dose of doxycycline might be effective for preventing other tick-borne illnesses such as Ehrlichia, Anaplasmosis, or Borrelia miyamotoi.

Today, patients expect to be informed of their treatment options. The recent review in the Journal of Emergency Medicine [1] would have been stronger if the authors had disclosed the evidence against using a single, 200 mg dose of doxycycline for prophylactic treatment of a tick bite.

Updated: August 29, 2022

  1. Applegren ND, Kraus CK. Lyme Disease: Emergency Department Considerations. J Emerg Med, (2017).
  2. Wormser GP, Dattwyler RJ, Shapiro ED et al. The clinical assessment, treatment, and prevention of lyme disease, human granulocytic anaplasmosis, and babesiosis: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis, 43(9), 1089-1134 (2006).
  3. Cameron DJ, Johnson LB, Maloney EL. Evidence assessments and guideline recommendations in Lyme disease: the clinical management of known tick bites, erythema migrans rashes and persistent disease. Expert Rev Anti Infect Ther, 1-33 (2014).
  4. Cameron DJ, Johnson LB, Maloney EL. Evidence assessments and guideline recommendations in Lyme disease: the clinical management of known tick bites, erythema migrans rashes and persistent disease from Expert Review of Anti-infective Therapy 2014 at
  5. Evidence assessments and guideline recommendations in Lyme disease: the clinical management of known tick bites, erythema migrans rashes and persistent disease. National Guideline Clearinghouse. Agency for Health Care Research and Quality. Available from:

53 Replies to "Single dose doxycycline for treatment of tick bite only prevents Lyme disease rash"

  • Prittam
    06/06/2020 (11:02 am)

    Hi, I was bit by a tick and i am not sure how long it was on me (likely 30 hours+). I was given a single dose of 200mg Doxy after taking the tick out.

    iIs been 5 days since then and I am getting a bit concerned that a single dose will not be enough. Should i start a 14 day Doxy treatment right now? Will the 14 day treatment be effective now that almost a week is past?

    • Dr. Daniel Cameron
      06/06/2020 (7:00 pm)

      The IDSA advises a single 200 dose of doxycycline. I follow ILADS guidelines that advise against a single dose of doxycycline. I prescribe a 3 to 4-week course with followup or observation with followup. Call my office in New York if you have any questions.

  • Amal
    06/03/2020 (1:15 am)

    I was diagnosed with chronic lyme four years ago. It took at least two years to get it under control. A couple of days ago, I pulled a deer tick out of me. I doubt it was in me for even six hours, but I went to my local doctor (my Lyme doctor doesn’t take insurance and lives far away) and demanded 3 weeks doxycycline and took my first dose in less than 24 hours after the tick was removed. However, I noticed that the doctor only prescribed three weeks of 100 mg, twice a day. So the first day I took 200 mg doses, now I’m on the regular 100 mg doses. Should I be taking any more precautions? Is the lower dosage putting me at significant risk?

    • Dr. Daniel Cameron
      06/03/2020 (7:46 am)

      I typically prescribe 100 mg twice a day for a tick bite if I am treating my patient prophylactically. I arrange for a followup visit before the end of treatment to evaluate the response to treatment.

      • Lori
        06/06/2020 (11:58 am)

        I had a tick removed from my back that was there for about 32 hours. This happened about 5 weeks ago.
        I already have chronic Lyme and Lyme Chardytis …
        I was diagnosed with lyne back in 2010, and 2014 for the heart problem. My doctor prescribed the one time dose of doxy… I’m not feeling well, should I demand a three week treatment of doxycycline?

      • Nicole
        05/14/2022 (2:36 am)

        Would this be the same for a 7 year old that weighs 43 pounds?

        • Dr. Daniel Cameron
          05/14/2022 (6:53 am)

          The study was quite small. There were 8 rashes in the treatment group and 1 in the placebo group. The authors only looked adults.

  • Hrip
    05/26/2020 (12:00 am)

    Hi There,
    I was bitten by tick around my neck 5 days ago, there is no sign of bullseye or other symptoms, but last night I found another little tiny tick on my upper body, I contact my primary doctor, she prescribed me 100MG Doxycycline 10 days for every 12 hours. I just want to make sure that if I’m on right track to follow ? Thanks for in advance

    • Dr. Daniel Cameron
      05/27/2020 (2:18 pm)

      The IDSA advocates a single 200 mg dose of doxycycline. ILADS favors 3 weeks. I advocate 3 to 4 weeks coupled with a followup visit.

  • m
    07/24/2019 (10:58 pm)

    wow I’m glad I found this website, aren’t you wonderful for answering everyone’s questions! I literally “felt” a bite on my leg yesterday, pulled up my pants and saw the tiniest black dot imaginable. The tick was easy to remove, totally see through belly and I don’t believe it was on me very long BUT that is only based on my feeling of the bite and the fact it isn’t engorged. I live on the island of Nantucket. New here, and everyone is screaming at me to take 2 Doxycycline immediately. Thing is, I am currently trying to get pregnant and have some symptoms that I may actually be pregnant. I will find out in a week. From the research I’ve done, I realize that the Doxycycline won’t mess with the pregnancy at this point. I guess, I’m curious what you would do. I moved here not that long ago but heard the Lyme here is real bad. Bite site is itchy, raised. Thing is, if I wait and I do have it, will it then be too late to do antibiotics with pregnancy. Good times. Guess I should’ve waited for late fall to begin trying 🙂 THANK YOU SO MUCH.

  • Rebecca Capman
    06/20/2019 (5:47 am)

    I was bitten yesterday by a female deer tick. I don’t think it was attached for more than 12 hours. I have a small red welt but it has faded significantly after about 14 hours. I have multiple sclerosis and a compromised immune system. I’ve notified my primary doctor and am waiting for her recommendation. What are your thoughts on my predicament?
    Thank you.

    • Dr. Daniel Cameron
      06/20/2019 (11:59 am)

      I wrote the Lyme Disease Science blog to reflect the differing views. I have been opposed to a one time 200 mg dose of doxycycline until they than show that the rx prevents chronic manifestations of Lyme disease. I either watch carefully with an evaluation and bloods a month later or a 4 week course of doxycycline with followup. I might treat someone with an underlying illness in part because I can’t be sure what is a manifestation of Lyme disease or their underlying illness.

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