For Clinicians | Antibiotic Eye Drops for Pink Eye

What the Evidence Says and What Schools Still Require

By Dr. Jamie Wilkey, PharmD — Director of Clinical Strategy, Jase
Medically reviewed and edited by Kristen Carpenter, PA-C

“But the school won’t take him back without the drops. I need them!“

That sentence gets said at pharmacy counters and repeated into phone triage every week by the frantic parents of kids with pink eye. A kid woke up with one lid crusted shut, the front office called by 9:15, and now a parent is standing in front of one of us needing an Rx so their child can go back to school or daycare.

So we write the script. Yep. About 69% of the time, going by the claims data.¹

Today we’re talking about what those antibiotic eye drops actually do. Then why the visit is usually about authorization rather than infection, the one presentation where antibiotics make a difference (it isn’t drops), and the short list of findings that should change the plan no matter what the school form says. Let’s jump into what to do about those goopy eyes that look awful.

Do antibiotic eye drops change the course of pink eye?

A little, in the cases that are actually bacterial, and not nearly enough to explain how often we reach for them.

The 2023 Cochrane review pooled 21 trials and 8,805 patients with acute bacterial conjunctivitis. About 55% of the placebo group cleared on their own by day four to nine, compared with 68% on antibiotics.² That works out to a number needed to treat of 7 for clinical cure, against a number needed to harm of 32 for ocular adverse effects with the non-fluoroquinolone drops.³ By day six to ten the two groups have mostly converged.

That is the ceiling on the benefit. It only applies to the bacterial cases. The problem here is that we cannot reliably tell which ones those are. AAFP’s 2024 clinical review states that no single sign or symptom accurately differentiates viral from bacterial conjunctivitis,⁴ and that includes the two findings most of us rely on, purulent discharge and morning matting. So the drops go out to a mixed population in which we cannot cleanly identify the patients who stand to benefit.

The prescribing data shows how that plays out. Across 44,793 pediatric ambulatory encounters, topical antibiotics were dispensed within a day for 72% of office-based visits and 57% of ED visits, but only 34% of eye clinic visits.¹ You could reasonably say that is specialty selection, since eye clinics see referrals rather than the 9:15 phone call. Fair enough. Then look at the encounters where viral conjunctivitis was the documented diagnosis, where there is nothing for an antibiotic to act on: 28% of those children got drops anyway.¹

The 24-hour rule is school policy, not a clinical standard

Nothing in pediatric guidance requires a child with pink eye to be on drops before going back to school or daycare. The AAP position, carried in the Red Book and in Managing Infectious Diseases in Child Care and Schools, is that a child with conjunctivitis and no fever and no change in behavior does not need to be excluded, and that otherwise healthy, well-appearing children with red, watery eyes should not be excluded or isolated at all.⁵ 

Now let’s check out what states actually publish. A 2022 survey of all 50 state policies found:

• 15 states have no conjunctivitis policy at all
• 10 allow students to stay in school
• 5 permit return 24 hours after starting antibiotics
• 5 require a physician’s approval
• 17 states plus DC give inconsistent recommendations, and not one state policy anywhere references the American Academy of Ophthalmology⁶

So the 24-hour rule that sends these families to us is written into state policy in five states.

Before we make the school nurse the villain, though: they are working from guidance that does not agree with itself. AAO’s own patient education page, updated August 2024, advises staying home until symptoms start to improve.⁷ AAP says don’t exclude. A district with no state guidance to point to picks the rule that sounds careful, and 24-hours-on-antibiotics is the one everybody has heard and feels better for parents who don’t want their kids to catch the goop eye from other kids in the class.

This is what gets awkward and that we weren’t really trained for. We were taught to make a clinical decision about an infection. What we are being asked for is authorization to re-enter a building, and it costs the family a visit and a copay to get it.

The drops are not buying a smoother course either. In that same pediatric cohort, ambulatory revisits within 14 days ran 3.1% among children who got antibiotics and 3.6% among those who did not, hospitalizations 0.03%, ED revisits 0.12%, with no differences between the groups.¹

Check out what your own state actually publishes before you write the Rx. In 15 of them, there is nothing to comply with.

Check the ears when you see the eye

There is one presentation where antibiotics clearly do the work, and the treatment is oral, not topical.

Conjunctivitis-otitis syndrome is a good one to remember in the back of your mind. Ear infections turn up alongside bacterial pink eye often. Published estimates run from 32% to 73%, and plenty of those kids never complain about ear pain.9 Haemophilus influenzae is the usual culprit. It was 70% of isolates in a cohort of 67 children with conjunctivitis plus a concurrent ear or sinus infection.⁸ Drops cannot reach the middle ear, so they do not fix the real problem. Close to 30% of US Haemophilus influenzae isolates resist ampicillin, and amoxicillin fails the same way, since the resistance is usually a beta-lactamase.¹⁰ Amox-clav holds up against almost all of them. So amox-clav or cefdinir here, not plain amoxicillin.

Look in the ears of every kid whose parent brings you a red, crusted eye, including the ones with no ear symptoms. If the ear is involved, you treat one infection with one oral antibiotic and the eye clears with it. That is the case where the right answer is an Rx, and it still isn’t drops.

What actually changes the plan

Short list, and none of it depends on sorting viral from bacterial (which is the point, since we cannot do that reliably anyway).

• Contact lenses. Any lens wearer with a red eye gets seen today, not tomorrow. Contact-lens-associated keratitis is most often Pseudomonas, and it can leave permanent central corneal scarring and vision loss even when treatment is prompt and appropriate.¹¹ ¹² Empiric coverage needs a fluoroquinolone, and these patients belong with ophthalmology.
• Moderate to severe pain, any change in vision, or photophobia. Not conjunctivitis territory anymore.¹¹
• Sudden heavy purulent discharge in a sexually active adolescent or adult. Treat as gonococcal until proven otherwise. It needs systemic ceftriaxone with empiric anti-chlamydial coverage and same-day ophthalmology, because untreated it progresses to corneal melting and perforation.¹³
• A baby under a month old.  Different illness, and it needs a clinician today rather than drops.⁷
• Not improving, or keeps coming back. Failure to respond and recurrent episodes both go to ophthalmology.¹¹
• Anything you find yourself wanting a steroid for. Steroids can slow corneal healing and raise intraocular pressure, and ‘needs steroids’ is itself a referral criterion.¹¹

The contact lens question is the one to build into intake. Your MA or tech can ask it before you ever walk in the room. It is most likely to get missed on a busy afternoon.

All other treatment is a warm cloth, hand hygiene, and a few days to pass.

Where preparation actually helps here

Look again at what the parent in the opener was offered. Two options: get an Rx, or keep the kid home. Nobody handed them the third thing, which was a plain statement of what their state and their district actually require and if the drops actually help the condition. That’s similar to most access problems we write about. Care is either fully authorized or fully unavailable, with nothing sanctioned in between. Usually the missing middle is a medication that should have been on the shelf before anyone needed it. Appropriate medical preparation means having the right thing ready before you need it, and sometimes the right thing turns out to be a warm cloth, four days, and knowing you are not cutting a corner.

The bottom line

Most pink eye clears on its own. Antibiotic drops help modestly in the cases that are bacterial, and we cannot reliably tell which ones those are. The 24-hour rule that sends these families to us is school policy, not medicine, and in most states nobody wrote it down at all.

Look in the ears, and know the short list that changes the plan. The rest is a conversation, and that conversation is worth more to the family than the prescription is, even if they really want that Rx when they walk in the door to see you.

Sources

1. Shapiro DJ, Geanacopoulos AT, Subramanian SV, et al. Antibiotic Treatment and Health Care Use in Children and Adolescents With Conjunctivitis. JAMA Ophthalmology. 2024;142(8):779-780. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2820326
2. Chen YY, Liu SH, Nurmatov U, et al. Antibiotics versus placebo for acute bacterial conjunctivitis. Cochrane Database of Systematic Reviews. 2023;3:CD001211. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD001211.pub4/full
3. Sonoda K, Takeuchi Y. Antibiotics for acute bacterial conjunctivitis. American Family Physician. 2023;107(6):581A-581B. https://www.aafp.org/pubs/afp/issues/2023/0600/mbtn-acute-bacterial-conjunctivitis.html
4. Winters S, Frazier W, Winters J. Conjunctivitis: Diagnosis and Management. American Family Physician. 2024;110(2):134-144. https://www.aafp.org/pubs/afp/issues/2024/0800/conjunctivitis.html
5. Children’s Mercy Kansas City. Conjunctivitis Care Process Model: Recommendations for Inclusion or Exclusion from Daycare/School, citing the AAP Red Book (2015) and the 2002 AAP / American Public Health Association child care exclusion recommendations. https://www.childrensmercy.org/health-care-providers/evidence-based-practice/cpgs-cpms-and-eras-pathways/conjunctivitis-care-process-model/recommendations-for-inclusion-or-exclusion-from-daycare-school/
6. Lee T, Kuo IC. Survey of state conjunctivitis policies for school-age students. Journal of AAPOS. 2022;26(3):115.e1-115.e5. https://pubmed.ncbi.nlm.nih.gov/35378302/
7. Mukamal R. When Do You Need Antibiotics for Pink Eye (Conjunctivitis)? American Academy of Ophthalmology, reviewed by Rupa K. Wong, MD, August 26, 2024. https://www.aao.org/eye-health/tips-prevention/over-prescription-antibiotics-pink-eye
8. Hu YL, Lee PI, Hsueh PR, et al. Predominant role of Haemophilus influenzae in the association of conjunctivitis, acute otitis media and acute bacterial paranasal sinusitis in children. Scientific Reports. 2021;11. https://pmc.ncbi.nlm.nih.gov/articles/PMC7794412/
9. Conjunctivitis and Conjunctivitis-Otitis Syndrome. Pediatric EM Morsels. https://pedemmorsels.com/conjunctivitis-and-conjunctivitis-otitis-syndrome/
10. Potts CC, Rodriguez-Rivera LD, Retchless AC, et al. Antimicrobial Susceptibility Survey of Invasive Haemophilus influenzae in the United States in 2016. Microbiology Spectrum. 2022;10(3):e02579-21. https://pmc.ncbi.nlm.nih.gov/articles/PMC9241922/
11. Hashmi MF, Gurnani B, Benson S. Conjunctivitis. StatPearls. Updated January 26, 2024. https://www.ncbi.nlm.nih.gov/books/NBK541034/
12. Hatami H, Ghaffari Jolfayi A, Ebrahimi A, et al. Contact Lens Associated Bacterial Keratitis: Common Organisms, Antibiotic Therapy, and Global Resistance Trends: A Systematic Review. Frontiers in Ophthalmology. 2021;1:759271. https://www.frontiersin.org/journals/ophthalmology/articles/10.3389/fopht.2021.759271/full
13. Dvorak SF, Lee C. Hyperacute Gonococcal Conjunctivitis. Brown Hospital Medicine. 2025;4(4). https://bhm.scholasticahq.com/article/144966-hyperacute-gonococcal-conjunctivitis

For Clinicians | MenACWY vs MenB

A Back-to-School Meningococcal Vaccine Refresher

By Dr. Jamie Wilkey, PharmD — Director of Clinical Strategy, Jase
Medically reviewed and edited by Kristen Carpenter, PA-C

Fall is coming, and with that are newly minted college students heading off to live in the dorms. That means meningitis is particularly top of mind. While the disease itself isn’t seasonal, the vaccines feel like they are because this is the moment when parents and students consider them more than ever as many college forms require action with the vaccine. To add to the confusion, there are two separate vaccines, plus combination products. MenACWY is routine and MenB isn’t, exactly. And the two pentavalent products that cover both can’t be swapped for each other partway through a series.

Parents ask whether the shot their kid got at 11 still counts, and a fair number of us have to look it up before we answer. I know I do! The meningococcal schedule has been revised more than once since most of us trained, and the version we memorized had fewer moving parts.

So this is a refresher on meningitis vaccines for you: what’s routine, which products follow which, and what these vaccines don’t cover.

Which one does the college form actually require?

MenACWY, almost always.

CDC recommends MenACWY routinely for every adolescent, first dose at 11 to 12 and a booster at 16.¹ That’s what most state college-entry requirements are built around, and most of those apply to students living in on-campus housing rather than to everyone enrolled. The rules vary by state and they get revised, so check the state your student is moving to, not the one they’re leaving.

So when a family tells you “she already got the meningitis shot,” they almost always mean MenACWY, and they’re usually right that the form is handled. 

MenB is an option, not a default

So a parent will inevitably ask you in the next few weeks: “Does she need MenB too? What even is that?”

MenACWY covers four of the five serogroups that cause most disease. MenB covers the fifth. For a healthy teenager, MenB isn’t automatic. This bug gets killed by one particular part of the immune system, so when that part is missing, broken, or switched off by a medication, catching it is a much bigger deal. That’s kids without a working spleen, kids born with a gap in that defense, and anyone on eculizumab or a drug like it, which raises the risk roughly 2,000-fold.² Lab workers who handle the bacteria and anyone caught in a B outbreak, too.² All of them get MenB.

So why isn’t it routine for everyone else? Incidence is very low, and MenB gives what ACIP itself calls short-term protection.² Rare disease plus short-lived protection is a hard case for universal vaccination. Against that, serogroup B caused every US college outbreak from 2011 to 2019.³ Both of those are true at once, which is how this became a conversation instead of a rule. You and the family decide together if this vaccine is right, and ACIP calls that shared clinical decision-making.

Vaccine Schedules

This is the part that trips people up, and it’s the easiest one to miss on a records review.

There are two combination shots that cover all five serogroups in one injection: Penbraya from Pfizer and Penmenvy from GSK. 

• The MenB half has to match all the way through. Penbraya carries Pfizer’s MenB antigen, so the second MenB dose is Trumenba. Penmenvy carries GSK’s, so the second dose is Bexsero.⁴
• The two combination shots aren’t interchangeable with each other. Don’t start with one and finish with the other.⁴
• A combination shot is for the visit where the student is due for MenACWY and has already decided on MenB. It doesn’t replace the routine MenACWY schedule on its own.⁴
• MenB is two doses, 0 and 6 months, for healthy 16 to 23 year olds.² Start at 16 and the series is finished well before move-in.

So when a student turns up with a partial series, the question is which brand, not just which vaccine. If the record says “MenB” and nothing else, get the product name before you give dose two.

Why neither the shot record nor the rash rules bacterial meningitis out

Meningitis isn’t one disease. It’s inflammation of the meninges, and the causes run from enteroviruses to pneumococcus to Haemophilus influenzae type b to the occasional fungus. The shots we’ve been talking about cover exactly one of those organisms, and MenACWY covers only four of its five serogroups. “Meningitis vaccine” is a shorthand that promises a lot more than the vial delivers.

That chasm is where two kinds of false reassurance come from: the vaccine record and the rash. Neither one rules anything out.

First: “she’s vaccinated, so it can’t be meningitis.” MenACWY doesn’t cover B. No meningococcal vaccine covers pneumococcus, Hib, or any virus. And viral meningitis is the most common kind, usually self-limiting, with most people better in a week to ten days.⁵ Odds are good that what walks in to the clinic isn’t meningococcal. That’s the reassuring part, and it’s also why the shot record can’t rule anything out.

Second: the rash. In Thompson’s 2006 study of 448 children with meningococcal disease, the signs everyone watches for (rash, stiff neck, confusion) showed up at a median of 13 to 22 hours. The early ones (leg pain, cold hands and feet, off-color skin) showed up around 8 hours.⁶ What families watch for is what comes last. Know the glass test anyway, because parents ask: press a clear glass on the rash, and spots that don’t fade (petechiae and purpura) are the worrying kind. Bad thing to wait for, and harder to see on darker skin.

So instead of focusing on the symptom list when you counsel focus on the slope. A young adult who looks worse than the illness should make them look, and is worse hour to hour instead of day to day, is the one to send in.

If someone was actually exposed

Close contacts need prophylaxis fast, ideally within 24 hours. Who counts is decided by public health, not by proximity or by how worried someone is. That makes the list short to household members, roommates, and anyone directly exposed to oral secretions in the week before symptoms started. Something like a shared lecture hall or an interaction at a cash register doesn’t qualify.

Ciprofloxacin is also no longer the automatic choice. Resistant strains have been climbing since 2019, and CDC now tells health departments to prefer rifampin, ceftriaxone, or azithromycin in areas crossing two thresholds in a rolling year: two or more invasive cases caused by resistant strains, and 20% or more of cases resistant.⁷ New York went further in August 2024 and told providers to stop using cipro for this outright.⁸

Where preparation actually helps here

Most of what we do at Jase runs on a simple premise: for a short list of common, well-understood conditions, the clinical work can happen before the patient needs it, so nobody is sorting it out alone at 11pm. That’s what we mean by appropriate medical preparation.

Meningitis is where that premise stops. There’s no kit for this one. The preparation that helps a college student is a complete vaccination record and a low threshold for the ER when worrying symptoms appear.And nobody should be dosing themselves out of a standby antibiotic supply after a campus scare, a Jase kit included. That skips the resistance picture that decides the right drug, and it skips the contact tracing that decides whether they need anything at all.

We’re here for the times when primary care isn’t there, and this isn’t one of them. We’ll keep publishing where we draw these lines.

The bottom line

MenACWY is routine at 11 to 12 with a booster at 16, and it’s what the college form is asking about. MenB is a separate two-dose series under shared clinical decision-making, unless your patient is one of the people who gets it routinely. Brands don’t mix, so get the product name before dose two. And a shot record doesn’t rule meningitis out. When the slope is hours instead of days, that’s the ER.

Sources

1. CDC. Meningococcal vaccine recommendations for healthcare providers. https://www.cdc.gov/meningococcal/hcp/vaccine-recommendations/index.html
2. Mbaeyi SA, Bozio CH, Duffy J, et al. Meningococcal Vaccination: Recommendations of the Advisory Committee on Immunization Practices, United States, 2020. MMWR Recomm Rep. 2020;69(RR-9):1-41. https://www.cdc.gov/mmwr/volumes/69/rr/rr6909a1.htm
3. Marshall GS, Dempsey AF, Srivastava A, Isturiz RE. US College Students Are at Increased Risk for Serogroup B Meningococcal Disease. J Pediatric Infect Dis Soc. 2019;9(2):244-247. https://pmc.ncbi.nlm.nih.gov/articles/PMC7192401/
4. CDC. Use of the GSK MenACWY-CRM/MenB-4C Pentavalent Meningococcal Vaccine Among Persons Aged ≥10 Years: Recommendations of the Advisory Committee on Immunization Practices, United States, 2025. MMWR. 2026;75(1). https://www.cdc.gov/mmwr/volumes/75/wr/mm7501a2.htm
5. CDC. About Viral Meningitis. https://www.cdc.gov/meningitis/about/viral-meningitis.html
6. Thompson MJ, Ninis N, Perera R, et al. Clinical recognition of meningococcal disease in children and adolescents. Lancet. 2006;367(9508):397-403. https://pubmed.ncbi.nlm.nih.gov/16458763/
7. Berry I, Rubis AB, Howie RL, et al. Selection of Antibiotics as Prophylaxis for Close Contacts of Patients with Meningococcal Disease in Areas with Ciprofloxacin Resistance, United States, 2024. MMWR Morb Mortal Wkly Rep. 2024;73(5):99-103. https://www.cdc.gov/mmwr/volumes/73/wr/mm7305a2.htm
8. New York State Department of Health. State directs providers to discontinue use of ciprofloxacin to prevent meningococcal disease due to increasing antimicrobial resistance. August 14, 2024. https://www.health.ny.gov/press/releases/2024/2024-08-14_ciprofloxacin.htm

For Clinicians | Strep Throat vs. Sore Throat

Do You Need Antibiotics?

By Dr. Jamie Wilkey, PharmD — Director of Clinical Strategy, Jase
Medically reviewed and edited by Kristen Carpenter, PA-C

Most sore throats don’t need an antibiotic. Most of us already know that.

What’s harder to keep straight is the one patient who does, and what happens if that visit gets waved through like all the others. A kid with a sore throat, no cough, tender glands, running a fever, looks almost exactly like the kid down the hall with a garden-variety virus. The difference matters for antibiotic stewardship and, more importantly, for their health. Untreated Group A strep can progress to rheumatic fever: permanent heart valve damage that can show up weeks after the sore throat is long forgotten. Rheumatic fever is rare enough in the US that a lot of us learned about it as a historical disease that isn’t around anymore. But, it isn’t gone. It’s just rare enough, and quiet enough, that it’s easy to lose track of why the testing and treatment ritual around strep exists.

Today we’re talking about the tool that resolves that tension: the Centor score (McIsaac-modified for kids), what it tells you, and why the treatment on the other side of a positive test hasn’t changed in decades.

Do you need antibiotics for a sore throat?

Most of the time, no. The majority of sore throats, especially in adults, are viral. As you know antibiotics don’t affect a virus, and prescribing one anyway doesn’t get the patient better faster. It just adds an unnecessary drug, and an unnecessary risk, to their day. And contributes to antimicrobial resistance.

But roughly 5-15% of adult sore throats, and 20-30% of pediatric cases, are Group A strep. Symptom judgment alone doesn’t reliably separate the two: exudate can show up with mono, fever can show up with either, and “it just looks bad” isn’t a diagnostic criterion. The actual clinical problem isn’t “treat everyone” versus “treat no one.” It’s how to tell, reliably, which patient in front of you is which.

The four-question tool: the Centor score

The Centor score, McIsaac-modified with an age adjustment, turns that judgment call into a short checklist:

• Tonsillar exudate
• Tender anterior cervical lymphadenopathy
• Absence of cough
• History of fever
• Age adjustment: add a point for ages 3-14, subtract a point for ages 45 and up

Add it up. The score runs from -1 to 5, and each end points to a different action. A score of 0 or below means under 10% odds of an actual GAS infection: treat it as viral, skip testing. A score of 4 or 5 means over 50% odds: test to confirm if you want, but treating before the result comes back is reasonable. Everything in between, 1 through 3, is the test-before-you-decide zone, where a rapid strep swab settles it.

Take a 52-year-old with a cough, no exudate, no tender nodes, and no fever: zero criteria met, minus one for age 45 and up, for a total score of -1, the bottom of the range. Skip testing. Now take an 8-year-old with exudate, tender anterior cervical nodes, no cough, and a fever: four criteria met, plus one for age 3-14, for a total score of 5, the top of the range. Test and likely treat.

Using this little checklist in practice cuts unnecessary initial antibiotic prescribing by close to half, without missing the strep infections that matter. It settles the question directly: which patient in front of you actually needs the prescription.

When to test, and when the rapid test needs backup

A score in the test-before-you-decide zone (1 through 3) means swab and run a rapid antigen detection test (RADT). 

• Positive RADT: treat. No backup culture needed, in adults or kids. The test’s specificity is high enough to act on directly.
• Negative RADT in children and adolescents: back it up with a throat culture before ruling out strep. RADT sensitivity isn’t perfect, and this is the population carrying most of the rheumatic fever risk.
• Negative RADT in adults: no backup culture needed. The downstream risk is low enough that a negative result can stand on its own.

In practice, a lot of this happens before you’re even in the room. Plenty of practices swab everyone with a sore throat during rooming now, since newer RADT platforms turn around a result in about 15 minutes, often faster than the visit itself. That’s fine: RADT specificity is high enough that a positive result still means treat, even in a patient who scored a 0 and never should have been swabbed by the letter of the algorithm. The score’s real job in that kind of workflow isn’t gatekeeping who gets tested. It’s telling you how much to trust a negative, and in whom.

Why penicillin, still, after all these years

Once you’ve got a positive result, the treatment hasn’t changed: penicillin V or amoxicillin for a full 10 days. Group A strep has never developed resistance to penicillin. Which is impressive since clinicians have been prescribing it for decades for this. There’s no clinical reason to reach for a macrolide or a cephalosporin here unless the patient has a true penicillin allergy.

The full 10 day course really does matter too. The rheumatic fever prevention data behind this whole guideline was built on the 10-day course, not a shorter one, and stopping early is still the most common way an adequately-treated strep infection turns into a recurrence.

The bottom line

Most sore throats are viral, and most clinicians already know not to reach for the prescription pad on symptoms alone. The Centor score turns that instinct into a number: four questions that tell you which patient is worth testing, and which one just needs reassurance and time. When the test comes back positive, the treatment hasn’t changed in decades: penicillin or amoxicillin for the full 10 days.

We built Jase on that same idea: don’t guess who needs antibiotics, use a real framework to decide. Appropriate medical preparation takes the same logic behind the Centor score, defined criteria instead of a feeling, and applies it earlier: deciding ahead of time which predictable, self-limiting conditions are safe to prepare for before symptoms even start. In no way a replacement for a clinician’s judgment call. Just that same judgment, applied sooner.

Sources

1. Centor RM, Witherspoon JM, Dalton HP, Brody CE, Link K. The Diagnosis of Strep Throat in Adults in the Emergency Room. Medical Decision Making. 1981;1(3):239-246.
2. McIsaac WJ, White D, Tannenbaum D, Low DE. A clinical score to reduce unnecessary antibiotic use in patients with sore throat. CMAJ. 1998;158(1):75-83.
3. Shulman ST, Bisno AL, Clegg HW, et al. Clinical Practice Guideline for the Diagnosis and Management of Group A Streptococcal Pharyngitis: 2012 Update by the Infectious Diseases Society of America. Clinical Infectious Diseases. 2012;55(10):e86-e102.
4. CDC. Clinical Guidance for Group A Streptococcal Pharyngitis.
5. Hamilton JL, McCrea L. Streptococcal Pharyngitis: Rapid Evidence Review. American Family Physician. 2024;109(4):343-349.
6. Gerber MA, Baltimore RS, Eaton CB, et al. Prevention of Rheumatic Fever and Diagnosis and Treatment of Acute Streptococcal Pharyngitis: A Scientific Statement From the American Heart Association. Circulation. 2009;119(11):1541-1551.

For Clinicians | Head Lice Myths

Permethrin Resistance, and What Actually Works Now

By Dr. Jamie Wilkey, PharmD — Director of Clinical Strategy, Jase
Medically reviewed and edited by Kristen Carpenter, PA-C

A few years ago when I was working as a pharmacist a patient handed me a small plastic baggie. I thought it was empty as I was holding it and she asked, “Is this lice?” I turned it over, looking for whatever she wanted me to see. She asked again: “Is this lice??” She’d pulled it from her daughter’s head and needed someone behind a counter to tell her what she was looking at.

I’ve had patients hand me a lot of things over a pharmacy counter. I’d never had someone hand me a baggie of lice and ask me to identify it. Every time lice comes up, I think of that baggie and patient. Patients are asking about this and as we are headed back to school this month it is the perfect time for a lice refresher course for all of us.

Is head lice a sign of a dirty house?

Nope. Lice don’t care how clean the house is, how often the kid showers, or how expensive the shampoo is. If anything, lice attach more easily to clean hair than dirty hair, so the kid who washes every night isn’t safer than the one who skips a day (or three).

They also don’t come from the family dog or cat. Human head lice are species-specific: they feed on human blood and can’t survive on fur. The lice that show up on pets are a different species entirely, and they stay on pets.

The couch, the car seats, the stuffed animals are also fine. Lice survive 24 to 48 hours off a human scalp, so that outdated bagging-everything-in-the-house instinct is solving a problem that doesn’t really exist. Head-to-head contact is how lice spread, almost always. Not shared hats, not the family dog, not the couch cushions.

The house is fine. The nit still in her hair might get her sent home anyway.

What the AAP says about nits and school

Quick refresher, since this is where most of the confusion starts: a nit is the egg, not the bug. It’s glued to a hair shaft close to the scalp and takes roughly a week to hatch. A live louse is the actual insect, crawling and feeding on the scalp. Finding a nit doesn’t mean there’s an active infestation, especially once hair growth has carried it away from the scalp. Most of the panic, and most of the school policy, is built on the wrong half of that distinction.

Plenty of schools still send a kid home for a single nit, or won’t let them back until every last one is combed out. That policy has been out of step with the actual guidance for going on two decades now, and the AAP tightened its language further in 2022.

The AAP’s clinical report states that children shouldn’t be restricted from school attendance over head lice, given how low classroom contagion actually is.¹ It goes further than earlier guidance, too: screening for nits alone isn’t an accurate way to predict which kids are or will become infested, and school nit-checks haven’t been shown to reduce how much lice actually circulates in a school over time.

The distance rule is specific: nits found more than roughly a quarter inch from the scalp are usually already hatched or dead. Diagnosis is supposed to rest on finding a live louse, not counting nits.

Empower a parent who’s arguing with a front office over a nit check with that information, and they have something to bring back to the school.

Why doesn’t permethrin work like it used to?

A parent buys the same box of Nix everyone’s grandmother used, follows the instructions exactly, and the lice are still crawling around seemingly unfazed. In most of the country that’s not user error anymore. Resistance is here!

A 2016 study sampled lice from 138 sites across 48 states and tested them for the genetic marker tied to pyrethroid resistance. The average resistance-allele frequency came back at 98.3 percent, and 42 of the 48 states sampled had populations at 100 percent.² Permethrin resistance isn’t a pocket problem. In most US communities, it’s the baseline.

That marker measures the gene, not the treatment outcome in any one kid’s head, so it’s not a guarantee that a specific box of Nix will fail. But at that frequency, reaching for permethrin as a first-line fix is closer to hoping than treating.

So what actually works?

When first-line permethrin or over-the-counter pyrethrins fail, the next rungs aren’t exotic. They’re underused mostly because parents, and a fair number of clinicians, still think of Nix as the only option.

• Benzyl alcohol 5% lotion (Rx): works by asphyxiating lice rather than poisoning them, so permethrin resistance doesn’t carry over. Two applications, a week apart.
• Malathion 0.5% lotion (Rx): an organophosphate, still effective against most resistant populations. Flammable formulation, so no hair dryers or open flame during application.
• Spinosad 0.9% topical suspension (Rx): kills both lice and eggs, often effective in a single application.
• Ivermectin 0.5% lotion (Rx): a single 10-minute application cleared lice in 74 percent of patients at day 15 in trial, against 18 percent for the vehicle control.³
• Oral ivermectin (Rx): 400 mcg/kg on days 1 and 8 beat malathion lotion for treatment-resistant lice in trial.⁴ No ovicidal action, so the second dose is what catches nymphs that hatch in between. Off-label for lice specifically, and generally avoided under 15 kg over a theoretical CNS risk.

The practical marker for when to move up the ladder instead of reaching for another box of the same product: check 8 to 12 hours after treatment5. A few lice still moving slowly is normal, the medicine just needs time to finish the job. It’s a different story if you don’t find any dead lice at all, or the live ones look just as active as before treatment. That’s the point to switch classes, not double the dose.

A pharmacist can walk a parent through this ladder at the counter faster than most primary care visits allow.

The bottom line

The myths about lice haven’t caught up to the evidence, and neither has the drugstore treatment that used to work. The no-nit exclusion was never real AAP policy. A second failed box of permethrin isn’t bad luck anymore, it’s the baseline. Next time a parent hands you a baggie and asks if it’s lice, you’ve got a straight answer for the house, the school, and the drugstore shelf.

Sources

1. Nolt D, Moore S, Yan AC, Melnick L; American Academy of Pediatrics. Head Lice. Pediatrics. 2022;150(4):e2022059282.
2. Gellatly KJ, et al. Expansion of the Knockdown Resistance Frequency Map for Human Head Lice in the United States Using Quantitative Sequencing. Journal of Medical Entomology. 2016;53(3):653-659.
3. Pariser DM, Meinking TL, Bell M, Ryan WG. Topical 0.5% Ivermectin Lotion for Treatment of Head Lice. New England Journal of Medicine. 2012;367(18):1687-1693.
4. Chosidow O, et al. Oral Ivermectin versus Malathion Lotion for Difficult-to-Treat Head Lice. New England Journal of Medicine. 2010;362(10):896-905.
5. Centers for Disease Control and Prevention. Treatment of Head Lice. cdc.gov/lice/treatment.