Should people bitten by ticks be treated or not?
A 1992 study (below) concluded people should be treated with antibiotics when bitten by ticks. Choices the researchers considered- 1. Treat All (with 2 weeks of Doxycycline); or 2. Follow (to see if a rash appears then treat); or 3. Treat only those who have an EM rash and positive test after one month of exposure. Their results overwhelmingly supported the "Treat All" option.
In its 2006 highly controversial Lyme disease guidelines the authors chose to recommend the category- "Follow" (and then only if a laundry list of specific and almost impossible conditions were met)- rather than to "Treat All" even though the study results indicated a "Treat All" approach would have the "fewest major complications", "fewest complications overall" and was the "cheapest" method.
The IDSA also published that one dose of Doxycycline in some cases might be acceptable based on a study they had quickly put together citing the erroneous conclusion that people who didn't develop a rash didn't have Lyme disease, so after one dose of Doxycycline those with no rash must be "cured".
Knowing full well their theory was totally flawed, the IDSA still used the development of an EM rash, or not, as proof that someone had contracted Lyme disease, or not.
The fact that less than 50% of adults and less than 10% of children develop an EM rash was not factored into their conclusions. Even when the EM rash was the IDSA's determining factor of who had Lyme and who didn't, 87% of people in their own study who were treated with one dose of Doxy didn't develop a rash, but 13% DID get one. Do you feel lucky?
The one dose of Doxycycline theory is totally without justification, has been repeatedly refuted by competent researchers, yet it is still promoted today by the IDSA even although it is shamefully flawed and is considered to be dangerous. See the current recommendations for treating tick bites below this article (20 days of Doxycycline, 100-200 mg. 2 x day). If an EM rash does appear the new guidelines recommend additional treatment due to the unacceptably high failure rate of prescribing 20 days or less in clinical trials. Additionally, failure to fully eradicate the infection in the early stage may result in patients developing chronic Lyme disease.
Prevention of Lyme Disease after Tick Bites — A Cost-Effectiveness Analysis
David Magid, M.D., Brian Schwartz, M.D., M.S., Joseph Craft, M.D., and J. Sanford Schwartz, M.D.
N Engl J Med 1992; 327:534-541August 20, 1992DOI: 10.1056/NEJM199208203270806
Erythema migrans was classified as a minor sequela; cardiac, neurologic, and rheumatologic complications of late Lyme disease were considered major sequelae.
Treat All was the strategy of choice when the probability of infection was 0.036 or more, since it incurs the fewest major complications, has the fewest complications overall, and is cheapest.
For probabilities of infection between 0.036 and 0.01 the physician and patient must determine the strategy they prefer on the basis of their beliefs about the value of preventing major complications in relation to the dollar costs and the number of minor complications incurred. However, at these probabilities, Treat All appears to be the strategy of choice, since it still incurs the fewest major complications, while incurring only relatively few additional minor complications. As the probability of infection after a tick bite falls below 0.01, Follow becomes preferred, since the number of excess minor complications incurred by empirical antibiotic therapy greatly exceeds the number of major disease sequelae averted.
Finally, whereas this economic analysis considered only the relatively limited direct medical costs of managing the immediate sequelae of Lyme disease, consideration of nonmedical direct costs (e.g., travel costs incurred in the course of receiving medical care), additional out-of-pocket costs of care, direct medical costs incurred by patients with long-term complications, indirect costs (e.g., work loss), and intangible costs (e.g., pain and suffering) would increase the benefits of the Treat All strategy even more in relation to the other strategies.
Only a small portion of patients bitten by ticks are candidates for empirical treatment, because the large majority of bites are unrecognized. Hence, empirical therapy is not likely to reduce the number of cases of Lyme disease substantially.
For similar reasons, the potential for increased resistance to antibiotics as a result of empirical therapy is unlikely to be a substantial problem. Tetracyclines are commonly prescribed. The increase in use attributable to empirical therapy of patients with identifiable ixodes tick bites in areas of endemic disease is very small.
The efficacy of penicillin in killing Treponema pallidum, the spirochete with which we have the most experience, remains undiminished despite 40 years of extensive use.
The model used in our study suggests that this conclusion is correct when only minor complications are considered. At a probability of infection of 0.03, the incidence of minor complications (early Lyme sequelae plus minor reactions to antibiotics) is about equal for the Treat All and Follow strategies. The potential value of empirical therapy, however, is in preventing the cardiac, neurologic, and rheumatologic sequelae that may arise in persons infected with B. burgdorferi in whom erythema migrans does not develop.
When the probability of infection after a tick bite is 0.03, the model indicates that 640 extra cases of major Lyme sequelae are averted, but that only 7 additional cases of major drug reactions are incurred with the Treat All strategy.
In the six western states where I. pacificus is found, the prevalence of B. burgdorferiinfection ranges from 1 to 3 percent,4 , 43 and empirical therapy of tick bites is unwarranted. [Rates are currently higher than in 1992- treatment would be warranted. LB note]
In areas of New England, the Middle Atlantic states, and the upper Midwest, approximately 0.1 to 1 percent of larvae, 25 percent of nymphs, and 50 percent of adult I. dammini ticks are infected with B. burgdorferi.14 , 44 45 46 47 48 49Although tick infestations are highly localized, empirical therapy for tick bites should be considered in these areas. Recommendations for empirical therapy will need to be reexamined as better information on tick-infection rates (e.g., on a county-by-county basis) and the risk of infection after tick bites becomes available. Determinations of the efficiency of infection with B. burgdorferi through tick bites and the factors influencing the risk of infection should be major research priorities, given the importance of this information in patient care.
The duration of the tick's attachment may be a critical factor in spirochete transmission. Studies in animals suggest that there is little risk of infection within the first 24 hours, a risk of approximately 50 percent after 48 hours, and almost universal infection after 72 hours of attachment or if an infected tick feeds to engorgement.49 ,50 However, the generalizability of these findings to humans is unknown, and accurate estimation of the likelihood of transmission is difficult because of difficulty in assessing the duration of tick attachment and the degree of tick engorgement.
The detection of B. burgdorferi infection in an early, asymptomatic stage offers the potential to reduce unnecessary antibiotic treatment of uninfected patients and adverse reactions to antibiotic therapy, while minimizing disease sequelae in untreated patients.
Unfortunately, currently available serologic tests for B. burgdorferi infection are not sufficiently sensitive. The strategy of treating only patients who have erythema migrans or who have a positive antibody test for Lyme disease one month after tick exposure is reasonable only if the sensitivity of the test exceeds 0.90, and then only for patients in whom the probability of B. burgdorferi infection is between 0.01 and 0.02.
At probabilities of infection higher than 0.015, Treat All would both prevent more major complications than Follow and cost less. At probabilities of infection less than 0.015, the Treat All strategy would prevent more major complications than Follow but would cost more.
At probabilities of infection ranging from 0.036 to 0.055, Treat All would incur more minor complications than Follow, but it would prevent more major complications and would be associated with fewer complications in all. For probabilities of infection of less than 0.036, Treat All would result in more than one additional minor complication for each major complication prevented.
MORE SELECTED QUOTES
In response to IDSA authors comments supporting their way of doing things rather than using the study results to make recommendations, the original authors responded...
The estimated 2 to 6 percent rate of adverse reactions to doxycycline used in our study reflects the best published data. Nadelman et al. reported a rate of 31.7 percent for adverse events (all of which were minor, requiring discontinuation of treatment in only one patient) among patients who received larger doses for longer periods -- factors that are correlated with increased adverse reactions3. The conclusions of the model are not altered substantially even by significantly increased rates of minor complications of tetracycline treatment.
The estimate that erythema migrans develops in 60 to 80 percent of patients with Lyme disease is consistent with the published literature5. Our model predicts that there will be only six to seven cases of Lyme sequelae without erythema migrans per 1000 tick bites if 30 percent of ticks are carriers, and this estimate does not differ from pooled estimates derived from randomized trials.
Current Recommendations for Treating A Tick Bite
Clinicians should not use a single 200 mg dose of doxycycline for Lyme disease prophylaxis (Recommendation, very low-quality evidence).
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 (Recommendation, very low-quality evidence).
During the initial visit, clinicians should educate patients regarding the prevention of future tick bites, the potential manifestations of both early and late Lyme disease and the manifestations of the other tick-borne diseases that may have been contracted as a result of the recent bite.
Patients receiving antibiotic prophylaxis should also be given information describing the symptoms and signs of a Clostridium difficile infection and the preventative effect of probiotics. Patients should be encouraged to immediately report the occurrence of any and all tick-borne disease manifestations and manifestations suggestive of a C. difficile infection (Recommendation, very low-quality evidence).
PLEASE READ THE GUIDELINES.