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GuidelinesIDSA vs ILADS: Two Lyme Guidelines Compared
Two medical groups give different advice on tick bites, treatment length and lingering symptoms. Here is what each guideline actually says, side by side.
Quick answer
Two medical groups publish Lyme disease guidelines that often disagree. The IDSA/AAN/ACR 2020 guideline, which CDC’s clinician guidance follows, uses strict criteria and short antibiotic courses. The ILADS 2014 guideline recommends longer courses and leaves more room for each clinician’s judgment. Both rated the same research but reached different conclusions. Beat Lyme does not endorse either one.
- IDSA/AAN/ACR (2020): written by a joint panel of the Infectious Diseases Society of America, the American Academy of Neurology and the American College of Rheumatology. It covers prevention, diagnosis and treatment of most forms of Lyme. CDC says its treatment regimens are consistent with this guideline.
- ILADS (2014): written by the International Lyme and Associated Diseases Society. It covers three questions only: what to do after a known tick bite, how to treat the EM rash, and whether to retreat people whose symptoms persist.
- Both groups say they used GRADE, a common system for rating evidence. IDSA rated most of its key treatment evidence moderate or high quality. ILADS rated the evidence for its three questions very low and gives more weight to clinical judgment.
If you have Lyme disease, or think you might, you may hear two very different plans from two different doctors. This page explains where that difference comes from, side by side, using what each guideline actually says. It is here to help you ask better questions, not to pick a side for you.
Who the two groups are
IDSA, AAN and ACR. The Infectious Diseases Society of America worked with the American Academy of Neurology (neurologists) and the American College of Rheumatology (joint and immune specialists) on the 2020 guideline. Its 36-member panel also included family doctors, pediatricians, internists, a microbiologist, a cardiologist, groups from Canada and Europe, three patient representatives and one consumer representative. Several other medical societies reviewed and endorsed it.
ILADS. The International Lyme and Associated Diseases Society describes itself as a nonprofit, international, multidisciplinary medical society. On its website, ILADS says it was founded by physicians and scientists responding to patients who reported that common antibiotic regimens had not restored their health. Its 2014 guideline replaced an earlier 2004 version, and in 2024 it published a guidelines statement summarizing its current recommendations.
How each guideline was made
Here is how each group describes its own process.
IDSA/AAN/ACR. An independent technical team at Tufts Medical Center ran systematic literature searches (in 2016, updated in 2017 and 2019), screened the studies and rated their risk of bias. Abstracts, letters and unpublished data were left out on purpose. The panel then rated the certainty of the evidence with GRADE and labeled each recommendation strong (“we recommend”) or weak (“we suggest”). Panel members had to disclose financial and other interests, which a review group from the three societies assessed. The societies say they check about every two years whether new research means the guideline needs updating.
ILADS. ILADS says it adopted GRADE too. A working group picked three questions, searched the literature, rated the quality of the evidence and weighed the role of patient preferences for each one. Drafts went to the full panel, which was the ILADS board of directors, and then to outside reviewers. ILADS treated financial ties above $10,000 a year that were not part of medical practice as potential conflicts and reported that no panel member had one.
Why they still disagree. ILADS rated the evidence on all three of its questions as very low quality. Its guideline says that when evidence is weak, a panel’s values carry more weight, and that different panels reading the same studies can reach different conclusions. ILADS put a high value on preventing chronic illness and on leaving clinicians free to use judgment. IDSA, for its part, put a high value on avoiding harm from antibiotics and IV lines that its panel did not think were helping.
Who follows each guideline
The IDSA/AAN/ACR guideline is the mainstream U.S. guideline. CDC’s treatment information for clinicians says its regimens are consistent with it.
The ILADS guideline is followed by some clinicians, who are often called “Lyme-literate” doctors by patients. That is an informal term, not a medical specialty. ILADS’s website has a provider search. Seeing a clinician who follows either guideline is a personal choice to make with full information.
Side by side: six key differences
Each box below compares one topic. “Evidence rating” means how each group rated its own evidence; neither rating is ours. We list how long treatment lasts but never doses. Your prescriber sets those.
1. After a tick bite
This is one of the clearest splits. IDSA limits preventive antibiotics to bites that meet three strict criteria. ILADS recommends offering them for any known blacklegged tick bite where the tick fed. ILADS argues a single dose may fail and leave antibody tests negative, which it worries could delay diagnosis. See our first 72 hours after a tick bite guide for practical steps.
Preventing Lyme after a tick bite
| IDSA / AAN / ACR2020 guideline (followed by CDC) | ILADS2014 guideline | |
|---|---|---|
| Who is offered antibiotics | Only people with a high-risk bite: an identified blacklegged (Ixodes) tick, in a highly endemic area, attached 36 hours or more, with treatment started within 72 hours of removal. Otherwise, wait and watch. | Anyone with a known blacklegged (Ixodes) tick bite where there is evidence the tick fed, no matter how engorged it was or how common infected ticks are locally. |
| Preferred approach | A single dose of doxycycline, preferred over watching alone. | Recommends against the single dose. Preferred: a 20-day course of doxycycline; other options case by case. |
| Evidence rating (their own) | Strong recommendation; high-quality evidence for limiting it to high-risk bites, moderate-quality for the single dose. | Recommendation based on very low-quality evidence. |
2. Treating the EM rash
Both groups name the same main antibiotics. They disagree on how long to take them. ILADS judged failure rates in trials of 20 days or fewer to be too high; IDSA found shorter courses work as well as longer ones. More on the rash itself is on our Lyme disease rash page, and on treatment options in our Lyme disease treatment guide.
Treating the erythema migrans (EM) rash
| IDSA / AAN / ACR2020 guideline (followed by CDC) | ILADS2014 guideline | |
|---|---|---|
| Antibiotics named | Doxycycline, amoxicillin or cefuroxime axetil by mouth. Azithromycin is the second choice for people who cannot take the others. | Amoxicillin, cefuroxime or doxycycline first. Azithromycin is also acceptable, especially in Europe. |
| Length of first course | 10 days of doxycycline, or 14 days of amoxicillin or cefuroxime axetil, rather than longer courses. Azithromycin: 5 to 10 days. | 4 to 6 weeks of amoxicillin, cefuroxime or doxycycline, or at least 21 days of azithromycin. Recommends against courses of 20 days or fewer. |
| If you are not fully better at the end | No extra antibiotics for nonspecific symptoms like fatigue or pain unless there is objective evidence of ongoing infection or treatment failure. | Reassess right after treatment ends, and continue antibiotics for people who have not fully recovered, tailored to how well they responded. |
| Evidence rating (their own) | Strong recommendation; moderate-quality evidence. | Recommendation based on very low-quality evidence. |
3. Testing and diagnosis
The 2014 ILADS guideline is about treatment and does not cover testing in depth. To be fair to both sides, the box below uses the ILADS guideline where it touches on tests and ILADS’s published statement for its general view. Our Lyme disease test page explains how testing works.
Testing and reading the results
| IDSA / AAN / ACR2020 guideline (followed by CDC) | ILADS2014 guideline | |
|---|---|---|
| How diagnosis is made | A typical EM rash after possible tick exposure in an endemic area is diagnosed by its look, without lab tests. Other forms of Lyme rely on two-tier antibody testing, read alongside symptoms, history and risk. | The 2014 guideline makes no testing recommendations. ILADS’s separate statement on guidelines calls Lyme a clinical diagnosis based on history and exam, supported by lab tests when indicated, and warns against over-relying on tests. |
| A negative test | Often negative in the first days to weeks; as few as 20% test positive within a week of a single EM rash. A negative IgG test after months of untreated symptoms essentially rules Lyme out, barring lab error or a rare immune problem. | Notes that “seronegative” Lyme (infection with negative antibody tests) has been documented, and that a negative result would not necessarily stop clinicians from offering treatment. |
| Checking whether treatment worked | Antibodies can stay for years after the infection is gone, so a positive test cannot tell past from current infection. | There is no test of cure, so clinicians should reassess patients after treatment and as needed. |
4. Symptoms that persist after treatment
CDC notes that most people recover with 2 to 4 weeks of antibiotics, but some have lasting fatigue, body aches or trouble thinking, and the cause is unknown. This is where the two guidelines differ most. Read more on our chronic Lyme disease and post-treatment Lyme disease syndrome pages.
Symptoms that last after treatment
| IDSA / AAN / ACR2020 guideline (followed by CDC) | ILADS2014 guideline | |
|---|---|---|
| More antibiotics? | Recommends against more antibiotics for ongoing fatigue, pain or thinking problems when there is no objective sign of reinfection or treatment failure (such as arthritis, meningitis or neuropathy). | Discuss retreatment with everyone who has persistent symptoms. After ruling out other causes, the panel judges retreatment appropriate for most who remain ill; watching is an option for mild cases. Starting point: 4 to 6 weeks, adjusted to the person. |
| What may cause them | The evidence does not support treating lingering symptoms as ongoing infection. In placebo-controlled trials, people improved on antibiotics and on placebo alike. | Lists several possible causes, including immune changes, tissue injury, missed co-infections and ongoing infection. The panel says the weight of the evidence supports persistent infection, though causes may vary from patient to patient. |
| Risks named | IV-line complications, serious allergic reactions, a gallbladder problem needing surgery, frequent diarrhea; prolonged IV therapy has been linked to documented deaths. | In four retreatment trials, 6.8% had a serious adverse event, all tied to IV ceftriaxone or the IV line; 60 days of oral doxycycline had none. Long-term antibiotics need close supervision. |
| Evidence rating (their own) | Strong recommendation; moderate-quality evidence. | Strong recommendation to discuss retreatment; very low-quality evidence. |
5. Neurologic Lyme
IDSA has detailed advice for Lyme that affects the nerves, brain or spinal cord. The 2014 ILADS guideline does not address it as a separate question, so the comparison here is limited. See neurological Lyme disease for symptoms and care.
Neurologic Lyme
| IDSA / AAN / ACR2020 guideline (followed by CDC) | ILADS2014 guideline | |
|---|---|---|
| Meningitis, facial palsy, nerve-root pain | IV ceftriaxone, cefotaxime or penicillin G, or doxycycline by mouth, usually for 14 to 21 days. IV treatment is recommended when the brain or spinal cord tissue itself is involved. | Not covered as its own question. The 2014 guideline addresses only tick bites, the EM rash and persistent symptoms. |
| Thinking or memory problems that linger after treatment | No more antibiotics without objective evidence of ongoing infection (see above). | Discuss retreatment; options range from oral antibiotics to injectable or IV antibiotics, depending on severity and past response. |
6. How decisions get made
Underneath the details is a difference in philosophy. IDSA leans on fixed, evidence-graded criteria. ILADS leans on individualized judgment and shared decision-making when evidence is thin.
How decisions get made
| IDSA / AAN / ACR2020 guideline (followed by CDC) | ILADS2014 guideline | |
|---|---|---|
| How it was built | Systematic reviews by an independent technical team at Tufts Medical Center; 36-member panel of infectious disease, neurology, rheumatology and other specialists, plus 3 patient representatives and 1 consumer representative. | A working group chose 3 questions, reviewed the literature and rated it; drafts went to the full panel (the ILADS board of directors) and outside reviewers. |
| Role of the clinician’s judgment | Recommendations are labeled strong (“we recommend”) or weak (“we suggest”) and are meant to support shared decisions between clinicians and patients. | Places a high value on clinical judgment: guidelines should not limit it without strong evidence, and should not be used as fixed treatment protocols. |
| Role of patient preferences | Considered alongside cost, availability and antibiotic stewardship when options are similar. | Every recommendation rates how much patient preferences should matter, and calls for shared decision-making. |
What this means for you
You do not need to become an expert in guidelines. You do deserve to understand the plan you are offered and why. These questions work with any clinician, whichever guideline they follow:
- What makes you think this is (or is not) Lyme disease? What else could it be?
- Which guideline are you following, and why?
- How long is this treatment, and how will we know if it is working?
- What are the risks of this treatment, and of not treating?
- What signs should make me call you or seek care right away?
- If I am not better at the end, what is the next step?
About long antibiotic courses. Both guidelines name risks. IDSA reports IV-line complications, serious allergic reactions and other harms in retreatment trials, and links prolonged IV therapy to documented deaths. ILADS reports that serious events in those trials were tied to IV ceftriaxone or the IV line, and says long-term antibiotics should only happen under close supervision. Both urge clinicians to look for other causes of symptoms before giving more antibiotics.
Second opinions. It is reasonable to ask for a second opinion, especially when two clinicians disagree. Bring your records, test results and a symptom timeline. Our guide to preparing for your Lyme doctor visit can help.
Do not start, stop or change antibiotics on your own. Get prompt medical care if you notice a drooping face, fainting, chest pain, a racing or pounding heartbeat or shortness of breath. These can be signs that Lyme has spread to the nerves or heart (IDSA/AAN/ACR guideline).
We are collecting real experiences about getting different advice from different Lyme doctors from people who have lived it, shared with their permission. As stories come in, they will appear here, clearly marked as personal experience rather than medical advice.
Beat Lyme does not endorse either guideline. This page is general information, not medical advice. Talk with your own clinician about your situation. To keep learning, visit Step 7: Learn and connect.
Frequently asked questions
Which Lyme guideline does CDC follow?
CDC’s treatment information for clinicians says its regimens are consistent with the 2020 IDSA/AAN/ACR guideline, and it links to that guideline as its resource.
Is ILADS a real medical organization?
Yes. ILADS describes itself as a nonprofit, international, multidisciplinary medical society of clinicians and researchers. Its guideline was published in a peer-reviewed journal in 2014. Its recommendations differ from the mainstream IDSA/AAN/ACR guideline, and by its own rating the evidence behind them is very low quality.
What is a Lyme-literate doctor?
It is an informal term patients use, usually for clinicians who follow the ILADS approach. It is not a medical specialty or official credential. Whoever you see, ask which guideline they follow and why.
Are long courses of antibiotics safe?
All antibiotics carry risks, and longer or IV courses add more. IDSA reports IV-line complications and serious allergic reactions in retreatment trials. ILADS says long-term antibiotics should only be used under close supervision. Your clinician can explain the risks for you.
Are these guidelines up to date?
The IDSA/AAN/ACR guideline was published in late 2020, and its authors say they check about every two years whether it needs revising. The ILADS treatment guideline is from 2014; ILADS published a guidelines statement in 2024 summarizing its recommendations.
Sources
- IDSA/AAN/ACR: 2020 Guidelines for the Prevention, Diagnosis and Treatment of Lyme Disease (Lantos et al., Clin Infect Dis 2021;72:e1–e48)
- Cameron DJ, Johnson LB, Maloney EL. Evidence assessments and guideline recommendations in Lyme disease (ILADS). Expert Rev Anti Infect Ther 2014;12(9):1103–35
- ILADS: Treatment guidelines summary
- ILADS: Statement on guidelines (2024)
- ILADS: About ILADS
- CDC: Clinical care of Lyme disease