Lice eggs, called nits, are tiny teardrop-shaped specks that cling to individual hair strands close to the scalp. They’re about the size of a pinhead, usually white or yellow, and firmly glued in place so they won’t slide or flake off when you touch them. If you’re checking a child’s head (or your own) and trying to figure out whether what you’re seeing is actually a lice egg, the details below will help you identify them with confidence.
Size, Shape, and Color
A single lice egg is oval or teardrop-shaped, small enough that many people mistake them for a grain of sand or a tiny seed. They’re visible to the naked eye, but just barely. You’ll spot them most easily under bright light or with a magnifying glass.
Color is your best clue to whether an egg is alive or already hatched. Live eggs tend to look yellowish-brown or tan, sometimes with a slight sheen, because they contain a developing embryo. After the egg hatches, the empty shell (called a casing) turns white, translucent, or grayish. These empty casings stay glued to the hair and grow more noticeable over time as the hair grows out and carries them farther from the scalp.
Where They Attach on the Hair
Female lice lay each egg directly onto a hair shaft, cementing it in place with a glue-like substance that hardens around the hair. This cement is strong enough that normal brushing, washing, or scratching won’t dislodge it. You typically need a fine-toothed nit comb, specifically designed for this purpose, to pull them free.
Viable eggs are almost always found within about 6 millimeters (roughly a quarter inch) of the scalp. They need the warmth of the scalp to develop, and eggs that sit farther out on the hair shaft are either already hatched or dead. This is a practical rule of thumb: if every nit you’re finding is more than a quarter inch from the scalp, you’re likely looking at old casings rather than an active infestation.
How to Tell Nits From Dandruff
This is the most common source of confusion. Both nits and dandruff flakes can look white or yellowish, and both appear near the scalp. But they behave very differently when you try to move them.
- The slide test: Dandruff flakes fall off easily. You can brush them away with your fingers or a regular comb. Nits don’t budge. They’re cemented to the hair strand and resist being pulled off, even with your fingernails.
- Shape: Dandruff flakes are flat and irregular, like tiny pieces of dry skin (because that’s exactly what they are). Nits have a defined teardrop or oval shape that’s consistent from one egg to the next.
- Location: Dandruff sits on the scalp surface and scatters into the hair loosely. Nits are attached to a specific spot on the hair shaft, usually on one side, and stay there.
- Size: Dandruff flakes are often larger and more visible than nits. Nits are uniform in size and much smaller than most dandruff flakes.
Hair spray droplets and debris from hair products can also be mistaken for nits. The same slide test works: product residue flakes or slides off easily, while nits stay put.
What Nits Look Like Up Close
Under magnification, a lice egg reveals more structure. One end has a small cap called an operculum, which is the “lid” the baby louse pushes open when it hatches. The surface of the egg also has tiny breathing pores that allow air to reach the developing embryo inside. You won’t see these features without a magnifying glass or microscope, but they explain why nits have a slightly textured appearance rather than being perfectly smooth.
After hatching, the operculum flips open or breaks off, and the remaining shell looks hollow and flattened. These empty casings are the bright white specks most people notice first, because they’re more visible than the darker live eggs sitting closer to the scalp.
The Egg-to-Louse Timeline
A lice egg takes 6 to 9 days to hatch, with about a week being typical. The nymph that emerges is roughly the size of a pinhead and looks like a miniature adult louse. It takes another seven days for the nymph to mature into a full-grown louse capable of laying its own eggs.
Temperature matters. Eggs need consistent body heat from the scalp to develop. If an egg falls off the head (on a pillowcase or hat, for example), it can survive up to 10 days but won’t hatch at or below normal room temperature of about 68°F. Temperatures above 125°F for 10 minutes kill both eggs and live lice, which is why running bedding through a hot dryer cycle is an effective step during treatment.
Why Finding Nits Doesn’t Always Mean Active Lice
One of the most common mistakes is assuming every nit signals a problem that needs aggressive treatment. Both the American Academy of Pediatrics and the National Association of School Nurses have pushed back against “no-nit” school policies, where children can’t return to class until every egg is gone. Their reasoning is straightforward: many nits found during head checks are empty casings or dead eggs that will never hatch. Nits more than a quarter inch from the scalp are especially unlikely to be viable. And misidentification is extremely common, particularly when non-medical staff are doing the checking.
What matters most is whether you’re finding live lice or eggs close to the scalp. A head full of white casings far down the hair shaft, with no live bugs and no fresh eggs near the roots, typically means the infestation has already been treated or resolved on its own. If you’re finding tan or yellowish eggs right at the scalp line, those are the ones worth addressing.
Best Way to Spot Them
Wet the hair and use a fine-toothed nit comb under bright, direct light. Nits show up more easily on wet hair because the strands separate cleanly and the eggs catch the light. Work through small sections at a time, wiping the comb on a white paper towel after each pass. Against the white background, nits and live lice are much easier to see and identify. A regular comb or brush won’t pick up nits because the teeth are too widely spaced to catch something cemented to a single strand of hair.