Single dose doxycycline for treatment of tick bite only prevents 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:
- It was not designed to detect Lyme disease if the rash were absent.
- The 6-week observation period was not designed to detect chronic or late manifestations of Lyme disease.
- 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
Related Articles:
Single dose of doxycycline for Lyme disease led to poor outcome for 61-year-old man
Can’t trust single dose doxycycline to prevent Lyme disease
No evidence single doxycycline dosage for Lyme disease prevention is effective in children
References:
- Applegren ND, Kraus CK. Lyme Disease: Emergency Department Considerations. J Emerg Med, (2017).
- 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).
- 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).
- 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 https://www.tandfonline.com/doi/full/10.1586/14787210.2014.940900.
- 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: https://www.guideline.gov/content.aspx?id=49320.
J paull
03/28/2024 (10:50 pm)
Removed deer tick that I belive I acquired Wed. Afternoon, at what point it attached is not known, discovered and removed it Thurs. Mid-morning, not engorged. Contacted primary care Dr. Called in the 1x dose of Dox, have not picked up yet. Had the lymerix vaccine back in the day, would that provide any protection anymore, if it even did originally? I’m on the fence about taking the Dox. Thank you.
Dr. Daniel Cameron
03/29/2024 (4:25 pm)
I don’t think Lymerix offers any meaningful protection.
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?