A head louse is a tiny insect about 2 to 3 mm long, close to the size of a sesame seed, with a pale gray body whose color may vary. Look for three forms at once: oval eggs, called nits, glued to hair close to the scalp; pinhead-sized nymphs; and sesame-seed-sized adults that crawl, since lice cannot jump, hop or fly. Head lice live on the scalp, and can also appear in the eyebrows and eyelashes.
What Head Lice Look Like to the Human Eye
Head lice and nits can be visible with the naked eye, though the CDC adds that a magnifying lens may help you find crawling lice or nits. Adult and nymph lice are very small, they move quickly and they avoid light, which is what makes them hard to find, and the AAP says the same thing: live lice are hard to find because they avoid light and move fast. A fine-toothed louse comb may help. A tickling sensation, or the feeling of something moving in the hair, is one of the symptoms the CDC lists. Finding a live nymph or adult louse on the scalp or hair is the best way to diagnose head lice.
Nit, Nymph or Adult: Three Sizes, Three Looks
Lice look different at each stage of life, and the size you are squinting at tells you which stage you found.
| Stage | Size | Look | Where you find it |
|---|---|---|---|
| Nit (egg) | 0.8 mm long and 0.3 mm wide, about the size of a knot in thread | Oval, yellow to white; small white or yellow-brown specks | Attached firmly to hair within 1/4 inch of the base of the hair shaft |
| Nymph (young louse) | About the size of a pinhead, 1.5 mm | Like an adult head louse, but much smaller | On the scalp and hair; takes about seven days to mature into an adult |
| Adult louse | Roughly 2 to 3 mm long, about the size of a sesame seed | Body pale and gray, though color may vary | Mostly on the head, and also on the eyebrows and eyelashes |
After an egg hatches, the empty nit stays on the hair shaft, so a head can carry specks after the live insects are gone. Nits attached more than 1/4 inch from the base of the hair shaft are almost always hatched or dead, which makes distance from the scalp worth measuring. The CDC counts about six eggs a day from an adult female and the AAP puts it at up to 10, and the AAP says the cycle can repeat every three weeks if head lice are left untreated. If the egg stage is what you cannot read, see what lice eggs look like in a child’s hair.
Nits, Dandruff, or a Different Bug?
Touch it: nits are firmly attached to the hair, while dandruff, dirt and other particles are not. The AAP describes a sticky substance that holds a nit firmly in place, so it stays put where a flake would brush away. The AAP also says nits can be confused with dandruff, dirt particles or hair spray droplets, and the CDC is blunt about the consequence: misdiagnosis of head lice infestation is common. Not every small bug in a child’s hair is a louse, either. If what you caught does not match the sizes above, it is worth learning how to tell real head lice from look-alike bugs.
Lice Detection: Checking a Head Section by Section
A real check is slow, bright and systematic. The AAP’s method is to seat your child in a brightly lit room, part the hair, and look for crawling lice and for nits one section at a time, and MedlinePlus adds to part the hair all the way down to the scalp in very small sections. The AAP’s comb-out method is a second way to check: wet the hair, comb small sections with a fine-tooth louse or nit comb, wipe the comb on a wet paper towel, then examine the scalp, the comb and the towel before moving on, repeating until you have been through all the hair. The easiest place to find them is at the hairline at the back of the neck or behind the ears. Knowing what lice and nits look like on a comb helps you read that paper towel. The AAP notes the comb-out usually does not get rid of head lice on its own.
If you find live lice, the CDC’s treatment guidance is to check all household members and other close contacts, and to treat everyone infested, plus anyone they share a bed with, at the same time. The AAP says head lice medicine should be used only when it is certain that your child has living head lice, and to check with your child’s doctor before beginning any treatment and follow the package directions exactly as written.
Frequently Asked Questions
What does a mild case of lice look like?
A light case can look like nothing at all. The CDC says people with head lice may not have symptoms, particularly with a first infestation or when an infestation is light, and that it may take four to six weeks for itching to appear the first time. The AAP recommends regular checks as a good way to spot head lice before they have time to multiply. Quiet does not mean clear.
What do lice look like in blonde or light hair?
The AAP notes that some nits may blend in with some people’s hair color, making them hard to see, so a comb and a bright lamp are better than a quick scan on any hair color. Our post on lice in blonde hair explains how to check when contrast works against you.
Do chewing lice or lice on a pet look like head lice?
An insect you find on a pet is not a head louse. The CDC states that animals do not get or spread head lice. Head lice, or Pediculus humanus capitis, are parasitic insects that feed on human blood, and they spread mainly by direct contact with the hair of a person who has them. The CDC’s advice on spread is to avoid hair-to-hair contact during play and not to share combs, brushes, towels or hats.
What do piojos look like?
Piojos is the Spanish word for lice, so you are looking for the same insect: an adult about the size of a sesame seed, a nymph the size of a pinhead, and oval eggs, yellow to white, stuck to hair near the scalp. The check does not change with the word you use for it: bright light, small sections, a fine comb, and a careful look at the nape and behind the ears.
Does head lice look like a rash or sores on the scalp?
What you see may be the scratching rather than the insect. The CDC lists sores on the head caused by scratching, which can sometimes become infected with bacteria normally found on your skin, and explains that the itch is an allergic reaction to louse bites. The AAP adds that itching can last for weeks, even after the lice are gone. Head lice do not transmit any disease and are not considered a health hazard.
How Lice Lifters of Mercer County Can Help
If you have looked twice and still cannot tell what you are seeing, we can help. At Lice Lifters of Mercer County we check the whole family, in line with the CDC’s advice to check all household members and close contacts. When we find live lice, our professional lice treatment is non-toxic and finishes in one visit. Same-day appointments are available, and our 30 Day Guarantee applies when the whole family is checked. If you are unsure about what is in your child’s hair, book an appointment and bring everyone in together.
