You can check yourself for lice, and the check is worth doing: bright light, hair parted down to the scalp in small sections, a fine-toothed comb, and the comb wiped on a wet paper towel after every pass. A self-check is good at confirming lice, because one live louse settles it. It is weaker at ruling them out, since the back of your own neck is the hardest spot to see and the easiest place to find them.
What Proves You Have Lice, And What Only Looks Like It
Proof is a live louse. The CDC’s overview of head lice says finding a live nymph, meaning a baby louse, or an adult louse on the scalp or hair is the best way to diagnose a head lice infestation, and MedlinePlus, the consumer library run by the National Institutes of Health, says a diagnosis usually comes from seeing a louse or a nit. That is the bar. A live louse settles it, which is why the first job of a self-check is knowing exactly what you are looking for.
Head lice are parasitic insects that feed on human blood, and the shapes you are hunting are small. Adult head lice are roughly 2 to 3 mm long, about the size of a sesame seed, with bodies the AAP’s parent guide to head lice describes as usually pale and gray, though the color may vary. A nymph, the stage between egg and adult, looks like an adult louse but is about the size of a pinhead, around 1.5 mm. Eggs, called nits, are oval, about 0.8 mm long and 0.3 mm wide, roughly the size of a knot in thread, and usually yellow to white. Nits attach to the hair with a sticky substance that holds them firmly in place, and after they hatch the empty shells stay on the hair shaft.
Where a find sits on the hair matters as much as what it is. Lice lay and attach their eggs to hair close to the scalp, the AAP says, and eggs are usually found within four to six millimeters of it and do not survive farther away. The CDC’s version of the same rule uses inches: nits attached more than a quarter inch from the base of the hair shaft are almost always hatched or dead, and nits that far out cannot hatch and usually die within a week if they are not kept at the same temperature as those found close to the scalp.
The CDC also calls misdiagnosis of head lice infestation common, and the look-alikes are the same in CDC and AAP material: dandruff, hair spray droplets and dirt particles. The way to tell them apart is mechanical rather than visual. Nits are firmly attached to the hair; dandruff, dirt and other particles are not. A speck that slides along the shaft or lifts off is not firmly attached, so it is not a nit. The AAP adds that some nits blend in with some people’s hair color, which makes them hard to see even when they are right there. If what you found does not match any of this, how to tell lice from fleas and bed bugs in hair is a better next step than a treatment.
What a comb or your fingers turn up sorts into five findings:
| What you found | How the sources describe it | What it means |
|---|---|---|
| A crawling insect the size of a sesame seed | Adult head lice are roughly 2 to 3 mm long | A live adult louse is the best way to diagnose head lice |
| A moving speck the size of a pinhead | Nymphs look like adults but are very small, about 1.5 mm | A live nymph settles it the same way |
| An oval glued to a hair near the scalp | Nits are oval, 0.8 mm by 0.3 mm, yellow to white | Look within a quarter inch of the base of the shaft |
| An oval more than a quarter inch out, no lice found | Almost always hatched or dead | Probably an old infestation that does not need treatment |
| A speck that slides or lifts off the hair | Dandruff, dirt particles or hair spray droplets | Nits are firmly attached; these are not |
How To Run The Check On Your Own Head
Work in small sections under the brightest light you have, and let the comb do the finding. The AAP’s check is four steps: wet the hair, comb through it in small sections with a fine-tooth louse or nit comb, wipe the comb on a wet paper towel after each pass and examine the scalp, the comb and the towel, then repeat until you have combed through all of the hair. MedlinePlus puts the same idea more bluntly: part the hair all the way down to the scalp in very small sections.
- Light first. The AAP’s instruction is to seat the person in a brightly lit room and part the hair; daylight or every lamp you own both count.
- Two mirrors or a phone. The hairline at the back of the neck and the area behind the ears are, in the AAP’s words, the easiest place to find them, and they are also the places you cannot see. A hand mirror held behind your head, or a phone camera, puts that band in view.
- A magnifying lens. The CDC says head lice and nits can be visible with the naked eye, but a magnifying lens may help you find crawling lice or nits.
- Patience with moving targets. Adult and nymph lice are very small, move quickly and avoid light, which is why a quick look is not a check.
Concentrate where the evidence concentrates. The CDC says you will often see nits on hair behind the ears and near the back of the neck, so work that band slowly and look for ovals attached firmly close to the scalp. Hair texture comes into it: the CDC notes that lice may have claws better adapted for grasping the shape and width of some types of hair, but not others. If your hair is coily, our post on finding lice in coily hair covers that case. If the comb is new to you, our walkthrough on how to use a lice comb covers the stroke and the wipe in more detail.
If another adult is home, hand them the comb. The AAP’s instructions are written for one person checking another, and the hairline at the back of the neck and the skin behind the ears are easier to work through when you are not also holding a mirror. A solo check is the fallback, not the preferred setup, and nothing about doing it alone makes a find more or less real.
Can You Check For Lice Without A Comb?
You can look without a comb, and you can find lice that way, but an empty look is weaker evidence than an empty comb. The CDC’s position is that head lice and nits can be visible with the naked eye, while a fine-toothed louse comb may help you find lice and a magnifying lens may help you spot crawling lice or nits. MedlinePlus says you may need both the lens and the comb. So an eyes-only check still works in one direction: anything you positively identify counts.
What eyes alone struggle with is the absence of a find. Because adult and nymph lice are very small, move quickly and avoid light, the CDC says they may be difficult to find, and the AAP puts it plainly: live lice are hard to find. On top of that, people with head lice may not have symptoms, particularly with a first infestation or when an infestation is light. A comb changes the odds because it drags what is on the hair onto a wet paper towel, where you can study it in your own time instead of chasing it across a scalp.
No nit comb in the house tonight? The CDC says flea combs made for cats and dogs are also effective. Both the CDC and the AAP specify a fine-toothed louse or nit comb. The one thing worth doing with bare fingers is the attachment test: take hold of the speck and see whether it moves. Nits do not.
Where an eyes-only look does earn its keep is frequency. It is quick to lift the hair at your neckline under a bright bulb, and an insect the size of a sesame seed against scalp skin is the kind of thing that catches your eye once you know what you are looking at.
The Early Signs, And Why Itching Is Not One Of Them
The earliest sign you can act on is a louse or an egg near the scalp, because the symptoms run late. The CDC says it may take four to six weeks for itching to appear the first time a person has head lice, and the AAP gives the same window: up to four to six weeks after lice get on the scalp before the scalp becomes sensitive to lice saliva and begins to itch. The CDC also says people with head lice may not have symptoms, particularly with a first infestation or a light one. Our post on lice without itching covers how that plays out in a household.
When symptoms do show up, this is the set the CDC, the AAP and MedlinePlus name between them:
- Itching, which the CDC calls the most common symptom of head lice infestation and attributes to an allergic reaction to louse bites. The AAP says most of the itching happens behind the ears or at the back of the neck.
- A tickling feeling, or a sensation of something moving in the hair.
- Irritability and sleeplessness. MedlinePlus explains the sleep part: head lice are most active in the dark.
- Sores on the head caused by scratching, which can sometimes become infected with bacteria normally found on your skin.
None of that tells you how long the lice have been there, and the arithmetic is the argument for checking early rather than thoroughly later. The CDC’s numbers: nits take about a week, in a range of six to nine days, to hatch into nymphs; a nymph takes about seven days to mature into an adult; an adult female can lay about six eggs each day; and adult lice can live on a person’s head for about 30 days. The AAP’s version of the cycle is that eggs hatch in seven to twelve days depending on the surrounding temperature, nymphs become adults about nine to twelve days after hatching, and the cycle can repeat every three weeks if head lice are left untreated. An untreated case does not stay the size you found it.
You Found Something. What Happens Next?
Check everyone who shares the house before you buy anything. The CDC’s treatment guidance is to check all household members and other close contacts for head lice, and to treat all infested people, including anyone they share a bed with, at the same time. That sequence matters, because reinfestation after successful treatment sits on the CDC’s own list of reasons a treatment fails. Head lice do not transmit any disease and are not considered a health hazard, so this is a job to do carefully today, not a crisis to do badly in ten minutes.
On treatment itself, follow the label and the clinician rather than a hunch. The CDC says to treat head lice if you have an active infestation, that both over-the-counter and prescription medications are available, and to use the medicine as directed on the box or label. The AAP says head lice medicine should be used only when it is certain there are living head lice, and to check with the doctor before beginning any head lice treatment. MedlinePlus adds that you should check with your health care provider first if you want to use a treatment on a young child. One more detail that catches people out: the CDC says not to use a combination shampoo and conditioner, or conditioner, before using lice medicine.
- Skip the kitchen cures. The CDC says it does not have scientific evidence that suffocating head lice with mayonnaise, olive oil, margarine, butter or similar substances is an effective form of treatment, and the AAP names petroleum jelly, tub margarine and essential oils in the same breath, because no studies prove they work.
- Never gasoline or kerosene, which MedlinePlus and the AAP both call dangerous and flammable, and never medicines made for use on animals.
- No fogs or fumigant sprays. The CDC says they are not necessary to control head lice and can be toxic if inhaled or absorbed through the skin, and the AAP says not to spray pesticides in your home.
- Nothing plastic over a head. The AAP’s wording is blunt: never place a plastic bag on a child’s head.
If a treatment has already happened, the follow-up is a calendar rather than a feeling. The CDC says some medicines kill lice and eggs, in which case retreatment is usually not required, while others kill lice but not eggs and call for a second treatment about a week later, seven to nine days depending on the drug. After each treatment, its advice is to check the hair and remove nits and lice every two to three days for the next two to three weeks. Its list of reasons a treatment fails starts with misdiagnosis and includes not following the instructions and head lice resisting the medication, and the AAP notes that lice can be resistant to the active ingredients in over-the-counter treatments in some communities, with the likelihood varying across the country. Before you decide the medicine lost, check the calendar against the hatch window.
The house needs less than you think. The CDC says to machine wash and dry the clothing, towels and bed linens used in the two days before treatment, on the hot water cycle at 130 degrees Fahrenheit with high heat drying, to seal what you cannot wash in a plastic bag for two weeks, to soak combs and brushes in hot water of at least 130 degrees Fahrenheit for five to ten minutes, and to vacuum where the person sat or lay. It also says spending much time and money on housecleaning is not necessary to avoid reinfestation, that the risk from a louse that has fallen onto a rug, carpet or furniture is very small, and that lice will die within two days if they fall off a person and cannot feed. The AAP adds that you do not need to throw those items away. And none of it is a verdict on your housekeeping: getting head lice is not related to cleanliness of you or your environment, and MedlinePlus says personal hygiene has nothing to do with it.
Frequently Asked Questions
How do you get lice if you have not been around anyone?
Through close contact. The CDC says head lice mainly spread by direct contact with the hair of a person who has lice, and that they move by crawling, so they cannot hop or fly onto you from across a room. Less often, they travel on hats, scarves, coats, hair ribbons, combs, brushes and towels, or from lying on a bed, pillow or couch someone with lice used recently.
Is there a lice scanner or detector that finds lice for you?
The tools the CDC and the AAP name are a fine-toothed louse comb, which may help you find lice, and a magnifying lens, which may help you spot crawling lice or nits that the naked eye can technically see. Detection comes from light, small sections and a slow comb, plus a second person for the back of your head.
How do I tell whether a treatment worked?
Look for dead lice, not for empty eggs. The CDC says nits may stay in hair after treatment, but successful treatment will kill crawling lice. If a few lice are still moving slowly eight to twelve hours later, it says you do not need to reapply; if you find no dead lice, or they seem as active as before, the medicine may not be working. Talk to a healthcare provider before re-treating.
How often should I check my own head?
Often enough to beat the hatch cycle, which means on a schedule rather than after a scare. The AAP says regular checks are a good way to spot head lice before they have time to multiply. After a treatment the interval tightens, and MedlinePlus says to comb the hair every two to three days and keep going for two to three weeks to be sure that all lice and nits are gone.
My scalp itches but I did not find anything. What does that mean?
An itch is not a diagnosis, in either direction. Itching is the most common symptom of head lice, but the CDC says misdiagnosis of head lice infestation is common, and the AAP says itching caused by head lice can last for weeks even after the lice are gone. So an itch with nothing on the comb is a reason to look again in a few days, or to ask a clinician what else irritates a scalp.
Can head lice live anywhere other than the scalp?
They live mostly on the head, with eyebrows and eyelashes as the other places. The CDC says head lice usually live on your scalp and that you can find them mostly on your head, but also on your eyebrows and eyelashes; the MedlinePlus encyclopedia says the same. Insects found elsewhere on the body fall outside head lice guidance altogether, so that is a question for a doctor rather than a comb.
Can I pick up lice from a swimming pool, a hat or a pet?
Not from a pet, and a pool is unlikely. The CDC says animals do not get or spread head lice, that chlorine levels in pool water do not kill head lice, and that lice can survive under water for several hours but are unlikely to spread in a swimming pool. Shared combs, brushes, hats and sports helmets carry what the AAP calls a very small chance, and lice from a wig or hairpiece are extremely unlikely.
How do I get checked for lice if I cannot tell on my own?
Hand the job to someone who can see the back of your head. The CDC’s advice when you are not sure whether a person has head lice is to see your healthcare provider. The other route is a clinic: our clinics check the whole family. You can find a Lice Lifters clinic near you and have the whole household checked in one visit.
When You Would Rather Have Someone Else Look
The hardest part of a self-check is the back of your own head, and that is where a second set of eyes helps. Our clinics check the whole family, treatment is done in one visit, and same-day appointments are available. The in-clinic treatment is our enzyme-based solution: non-toxic, chemical-free, safe for all ages, with 99.9% efficacy. Lice Lifters stands behind it with our 30 Day Guarantee, which applies when the whole family is checked, so a household gets handled together rather than one head at a time. If your mirror and comb left you unsure, find a Lice Lifters clinic near you and bring everyone who shares a pillow with you.
