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:

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

  • Suzanne Meub
    08/30/2022 (8:34 am)

    What does the IDSA do all day ? Trying to manage tick born disease with 15 year old recommendation ? and that’s the standard of care ? Ludicrous.

  • Andrew Wheelan
    08/27/2021 (11:10 am)

    Dr Cameron, this is going to sound ridiculous, but I had over 5000 larval Lone Star Ticks on me on weds. I have been finding conflicting information on the ability of larval ticks to carry disease. They are so small, that it’s an almost guarantee that I have been bitten. I have no associated rash, etc and have been prescribed 14 days of doxy 100 mg. Does this course of action seem prudent, even though they are larvae? I currently have a trash bag full of my clothes and thousands of ticks, do you know of any researchers that may be interested in them? This is on Block Island, RI , where the Loan Star Tick is purportedly a new arrival.

    • Dr. Daniel Cameron
      08/30/2021 (7:03 pm)

      I don’t know of any doctors who are studying this issue. Your doctor has to determine the best treatment.

    • Brenda
      09/24/2022 (4:33 pm)

      Try UMASS they were testing and making a log of where ticks with Lyme were. Perhaps they would be interested?

  • Carol Hall
    11/11/2020 (9:13 am)

    Went hiking on Thursday. A deer tick was found feeding on my husband Saturday. While taking it off the skin it disintegrated. I then had nothing to test. 😢 Started a ten day course 100 mg doxycycline, 1 BID. Would you recommend to continue the antibiotic for the full 3 or 4 weeks? He is on his 4th day of antibiotics. He is handleing the antibiotic just fine and with all the unknown about trasmission from a deer tick ( which may or may not affect your quality of life) would your professional opinion be to continue longer? If so how much longer?

    • Dr. Daniel Cameron
      11/11/2020 (10:06 am)

      I prefer at least 3 to 4 weeks for a tick bite for prophylactic treatment with a reevaluation. Other doctors disagree.

      • Cari
        07/08/2021 (7:46 am)

        I got bit by a tick on my stomach 2 weeks ago. I got the one dose doxycyclone 6 days later. It’s now been a week and 2 days and the rash is bigger. Should I go back to the doc to get on more doxy?

        • Dr. Daniel Cameron
          07/08/2021 (9:26 am)

          I have been opposed to a single dose of doxycycline for a tick bite and not for a rash. Some small rashes reflect irritation from the tick. I would not ignore the rash. I would typically advise consulting a doctor.

  • Justin
    10/28/2020 (2:14 pm)

    Found an adult deer tick on my leg on Monday, 10/26, after feeling pain at the bite location. Red ring around the bite, tick slightly engorged. My guess is it was there for 24-48 hours. Pulled it off, called the doc, and was prescribed the single dose doxy. Took it that day. The ring has shrunk and I feel fine, but after looking into further, it seems that the single dose is not the optimal course of treatment. My question is, will having taken the doxy on Monday, waiting, and taking it again (provided I can convince my doc to give the prescription) be an effective treatment? Thank you.

    • Dr. Daniel Cameron
      10/28/2020 (6:41 pm)

      The risk of Lyme from a tick bite is low but it can happen. I review the risk and benefits of a 3 week course. I typically find a course of doxycycline effective for those I have treated.

  • Alan
    10/24/2020 (5:37 am)

    Just found a tick stuck to my stomach and pulled it off. So I’m looking for tick bite info and looking through your blog. I simply don’t understand why the medical profession can’t come up with better answers. Why don’t doctors just perscribe 100 mg doxycycline twice daily for three weeks for any tick bites as a preliminary treatment pending diagnosis for Lyme disease. Heck, if you have pimples, dermatologists will perscribe doxycycline for months or longer. So, in some cases, doctors are so cautious that they worry about a single antibiotic in other cases they happily dose for long term.

    • Dr. Daniel Cameron
      10/24/2020 (9:41 am)

      I agree. I share the risks and benefits with my patients.

  • Liss
    07/03/2020 (8:27 pm)

    Hello! My two, almost three year old, developed a EM Saturday morning. We went to pediatrician and they prescribed 2 weeks of amoxicillin, 250mg three times a day, for 14 days. We live in NC and don’t have knowledge but we have a dozen deer a day come into our driveway. They said it could be Lyme or STARI. Will this protocol work? Thank you for your assistance! Such a scary time!

    • Dr. Daniel Cameron
      07/04/2020 (7:30 am)

      Doctors differ regarding the length of treatment. I prefer 3 to 4 weeks of amoxicillin with follow-up before ending treatment to reduce the chances of chronic illness. That leaves the doctor responsible for weighing the benefits against the side effects. Amoxicillin does not work for other tick borne infections such as Anaplasmosis and Babesia. I don’t take care of children that age.

  • Veronica Dwyer
    06/27/2020 (5:28 pm)

    Hello. I a large expanding rash a few weeks ago. Went to minor care and was diagnosed with the largest ringworm ever seen by the doctor. Increasing fatigue and headaches caused me to seek a second opinion. I went to another Doctor who suspected Lyme prescribing a one dose 200 mg doxycycline but insurance company suggested 10 days 2×100 mg doxycycline. I am on the fourth day and still feeling miserable. Should I request the doxycycline prescription be longer than 10 days and is the antibiotic even working since I still feel terrible? After reading so much about one time dose not working I am afraid the 10 days isn’t enough.

    • Dr. Daniel Cameron
      06/27/2020 (6:17 pm)

      A single dose of doxycycline is only indicated for a tick bite and not a rash. I am opposed to a single dose. I favor a longer course of antibiotics and follow-before stopping. Call my office at 914 666 4665 if you have any questions.
      You can read more in the ILADS guidelines at

  • 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.

  • Tony Michaels
    06/17/2019 (7:38 pm)

    Tony Michaels

    Hi there – I found what I believe to be a male Lone Star tick on my waist this past Saturday afternoon. I am basing that assumption that it was a male Lone Star tick on photographic comparisons I have made between the tick I removed and various photos I have viewed on-line. I am not certain if the tick attached itself this past Friday afternoon while on a golf course or while I was in my backyard Saturday morning/afternoon. Based on the timeline, I believe the maximum time it could have been attached was 30 hours while the minimum time would be 5 hours. The tick didn’t seem to be engorged and I have saved it in a zip-lock bag. I phoned my GP earlier to get his feedback on what if any preventative actions I should take to prevent acquiring tick borne illness. He prescribed a single dose of antibiotic as a prophylactic treatment (which I believe to be is 2x 100 mg’s pills of doxycycline). While perusing various websites today to learn and research as much as I can about ticks and the diseases they spread, it appears to me that the Lone Star tick isn’t a primary Lyme Disease carrier but does transmit several other potential sinister illnesses. I guess my question is should I even bother to take the doxycycline or just wait it out to see if symptoms develop. Based on some of the posts above, it looks as though you would lean on not taking it. Sorry for the long winded note, but I am just trying to make an educated decision regarding this – Thank you so much in advance for any advice you might give.

    • Dr. Daniel Cameron
      06/18/2019 (4:55 am)

      Your question reflects the uncertainty. The single 200 mg dose of doxycycline advised does not apply to the lone star tick. I need to weigh the pros and cons of watching vs a 3 to 4 week course of treatment. I follow my patient whether I treat or not.

  • J Hemingway
    05/16/2019 (12:00 pm)

    Hi Dr. Cameron, former nurse with a deer tick bite yesterday. Unfortunately, I did not recognize it as a tick and it was there at least 3-4 days and was engorged when I removed. I am in NC. Frustrating afternoon of going to urgent care and making multiple calls to practitioners and pharmacists who could not offer or offered conflicting advice. The young PA (from NJ) at urgent care subscribes to the single dose doxy. Thankfully, while frantically researching in the waiting room, I came across the ILADS site. I showed it to the PA and asked to call (to clarify if the 20 day doxy was prophylactic or once symptoms appear). He had “no time” for this. I insisted on a 20 day script and called ILADS after leaving. They could not provide info. Or clarification. I sat there with the docy in my hand and thought well…I think I should take this. My nurse friend and I decided I should do the 200 mg “loading dose” yesterday, and now will continue with 100mg BID. I feel completely alone in this and am very disappointed, yet agai , in the lack of knowledge/awareness among physicians…particularly in an endemic area such as this ?! (I am from Canada). Please, Dr. Cameron, could you confirm that I am doing the right thing at this point ? (doxy for 20 days seems like a long time…yikes) In adfition, I don’t believe they test the ticks here in NC (PA did not know, nor did he call to find out).My entomologist (retired) friend here said to forget the testing of the tick. As far as testing myself, it appears there is controversy over the accuracy of those results as well….and which type and at what stage they should be done?? Do you recommend any testing? What is to be done after the 20 day prophylaxis? Thanks so much in advance, for your time and reply. Janet H.

  • Dan
    05/11/2019 (10:46 pm)

    I noticed a bullseye shaped bruise on my leg at the end of April but never noticed anything on me or felt a bite. The mark was about an inch across. I went to a doctor and they gave me the single dose of doxycycline incase it was a tick bite. The mark never grew and faded like any normal bruise. I never had any symptoms of lyme and still dont it has been 3 weeks now. Is there a chance the mark was not tick or lyme related? It kind of felt like a bruise when touched. It had a small red mark at the center. Could something else have bitten me? Just wondering if I should have a follow up for lyme even though I have had no symptoms?

    • Dr. Daniel Cameron
      05/13/2019 (12:33 am)

      The CDC set 2 inches in diameter as a guideline. Rashes under 2 inches can come from other causes including a bruise. I am not a fan of a one time single 200 mg dose of doxycycline. I would rather follow closely or treat at least 3 weeks. You can see the rationale in ILADS guidelines at

        04/21/2020 (7:33 am)

        What exactly is the downside of taking the dose if it might prevent infection?

        • Dr. Daniel Cameron
          04/22/2020 (1:24 pm)

          Some patients develop complications of Lyme disease. The single 200 mg dose of doxycycline may prevent the rash but not the complications e.g., Lyme encephalopathy. The single dose may lead to a negative test with not treat the illness.

          • Alex
            07/14/2020 (7:50 am)

            My wife had the single dose of Doxycycline and developed a 1 inch (uniform, not bullseye) rash at the bite which went away. No other symptoms. I’m afraid that we just stopped the rash and not the disease. It’s now a month since the bite, is it too late to do a 20-day additional Doxycycline prophylaxis?

          • Dr. Daniel Cameron
            07/15/2020 (7:07 am)

            I share your concerns that the single dose of doxycycline may have interfered with the rash.

          • You will have to work with your doctor.
  • Janice
    05/08/2019 (7:39 pm)

    Today I removed an embedded female nymph deer tick which was on me 12-20 hours I think
    I took it to the local health department and the tester said it did not look engorged – I will have the test results in 3 days.

    In early 1990’s I had severe late stage Lyme with
    Neurological , arthritic and cardiac symptoms and ended up doing over 3 months of rocephin.

    Because of the previous severe problem,should I start antibiotics now? Wait 3 days? If the health department says it is not engorged is that a very
    Definitive diagnosis? They tests for Lyme and Babesiosis only and they said about 20% risk factor

    My GP had suggested taking a Westen blot and Elisa antibody test in a few weeks but could that be too late ? I live in Connecticut/land of Lyme !
    Thank you so much Dr. Cameron for helping with this devastating disease.

    • Dr. Daniel Cameron
      05/09/2019 (11:31 am)

      Thanks for sharing a few of the unresolved issues following a tick bite. The 24 to 36 hour window before infection was initially based on a mouse model and then only of the spirochete. We now know that there are tick borne pathogens that are transmitted sooner. The tick can test negative if damaged during shipping or if your blood interfered with the testing. i have to had to weigh the risks and benefit of treatment for each patient given the limited research evidence.

  • Ben Wildes
    01/31/2019 (9:03 pm)

    I was given a single dose doxycycline treatment for tick bite at a walk-in clinic. Weeks later I went back because I felt like I had symptoms of Lyme. The doctor there said that they don’t do follow-up for lyme, and that I would have to find someone else. I was sick everyday for a few more weeks until I could convince another doctor to give me 20 days of doxycycline. I finally got better and I’m okay now. Do not trust the single-dose treatment.

    • Dr. Daniel Cameron
      02/01/2019 (1:00 am)

      I agree. I am sorry you had to suffer.

  • jz
    08/27/2018 (7:46 pm)

    Hi – If a prophylactic antibiotic is not the right course of action, what is a better approach?

    • Dr. Daniel Cameron
      08/28/2018 (5:17 pm)

      I prophylactic antibiotic is planed, the ILADS guideline recommend the following:
      Clinicians should promptly offer antibiotic prophylaxis for known Ixodes tick bites, in which there is evidence of tick feeding, regardless of the degree of tick engorgement or the infection rate in the local tick population. The preferred regimen is 100–200 mg of doxycycline, twice daily for 20 days. Other treatment options may be appropriate on an individualized basis (see remarks below). (Recommendation, very low-quality evidence).
      You can read the guidelines at

  • Marta O’Bosky
    04/16/2018 (3:11 am)

    I had also received 1 time dose to prevent Lyme. 2 months later came down with all the Lyme symptoms and 6 years later am still chronically ill with Lyme, Bartonella and Babesia. Years of antibiotics, herbs, supplements have done nothing. I’m in constant full body pain… they always talk about treating Lyme right away, but what about coinfections? So many people are not just infected with Lyme but also multitude of other infections. There needs to be early treatments that can treat them all.

  • Conrad Miller
    09/23/2017 (12:29 pm)

    The truth is that as soon as the tick injects its evil brew of germs and toxins into the bitten-person’s body, these are there and the organisms will multiply vs. the individual’s immune system. Rash or no rash the borrelia, erlichia, babesiosis et al organisms will be using one’s body as a medium, symbiotic or parasitic, with there no likely 48 hour time clock threshold existing for all potential Lyme Disease victims to begin being ‘diseased’ as once proclaimed by Stony Brook Lyme Physician Dattwyler..

  • Jennifer
    04/28/2017 (12:53 pm)

    I have asked this before and I ask it again….Is there proof that the tick has to be attached for 24 hours in order for the virus to pass from the host? I would like to check this study out. I can’t seem to find anything only that “that’s just how we roll attitude”. How do they know this? What were the tests done on? When did this take place? How many times was this proven in the testing? Where’s the proof?!

    • Joyce Dahlberg
      05/24/2017 (9:46 pm)

      The # of hours is just an opinion. There has been no research done on this. It is only assuming. If you read articles many have different length. It is beyond a pandemic. It is not being acknowledged to reduce fear only. In my opinion hell will break loose very soon. Just a few days ago a 8 year old died 10 days after going to the doctors and was given another diagnosis. She died from a co infection of lyme that can be transmitted as fast as within 15 minutes. Only by drastic measures will something be done. THE TIME HAS COME TO AVOID OUTDOOR ACTIVITIES which would result in something being done because MONEY TALKS when the economy collapses due to no recreational pursuits.

    • Lorna
      05/29/2017 (7:39 pm)

      I have had Lyme – the bullseye rash, etc. – with a tick attached for less than 24 hours.

    • Jeff Levy
      07/06/2017 (9:40 pm)

      Here is a brief video that answers this question:

  • Tricia
    03/20/2017 (4:16 pm)

    This is exactly how my daughter at 7 became chronically ill with Lyme disease and suffered for 6 years while being bedridden. Her pediatrician assured me that a single prophylactic course of Doxy would completely prevent Lyme. Her ignorance caused my daughter to lose years of her childhood/teen years.

  • Join the Lyme Conversation
    (Note: comments are moderated. You will see your comment after it has been reviewed.)

    Some html is OK