Head lice are small, wingless parasitic insects that live almost exclusively on the human scalp and feed on human blood. Although they primarily reside in the hair, finding evidence of them on bedding, such as a pillow, is a common concern during an infestation. Understanding the visual characteristics of lice, nymphs, and eggs helps accurately identify any specks or debris found away from the scalp.
What Lice and Nits Look Like
Adult head lice are approximately the size of a sesame seed, measuring about 2 to 3 millimeters long. They are typically tan to grayish-white and have six legs with hook-like claws designed to grasp hair shafts. These adults are fast-moving, which makes them difficult to spot when checking the hair.
The eggs, called nits, are minute, oval-shaped specks, about the size of a pinhead. Before hatching, nits may appear yellowish, white, or translucent, sometimes matching the color of the hair they are attached to. Unlike dandruff, a female louse glues the nit firmly to the hair shaft very close to the scalp, making it nearly impossible to brush off.
Nymphs are the newly hatched lice, and they look like smaller versions of the adults, starting at about the size of a pinhead. They are often translucent or lighter in color, making them harder to see than mature lice. As they grow, nymphs molt, or shed their outer layer, before maturing into full-sized adults.
Distinguishing Lice from Debris on Fabric
When examining a pillowcase or sheet, true nits are rarely found unattached, as the strong, waterproof glue keeps them cemented to a hair shaft. If a nit is found on the fabric, it is almost certainly attached to a shed hair. A person is more likely to find a live louse that has fallen off the head, or evidence left behind by the insects.
Adult lice found on a pillow appear as small, dark specks, similar in size to a sesame seed. Unlike dark lint, a louse is elongated in shape and may exhibit very slow, uncoordinated movement. They are typically dying or dead shortly after falling onto the fabric.
Other debris commonly mistaken for lice evidence includes shed exoskeletons, which are light-colored casings left behind when a louse molts. Small, dark reddish-brown specks may also be visible, representing fecal matter, often called “lice dirt.” Dandruff is flaky and easily brushes off the fabric, while fabric pilling or lint is fuzzy and varies in color and shape.
How Long Lice Survive Away From the Scalp
Head lice are obligate parasites, meaning they require the human host for survival, needing to feed on blood multiple times a day. Once an adult louse falls off the scalp and onto a pillow, it dies relatively quickly. Adult lice and nymphs cannot survive for more than 24 to 48 hours without a blood meal and the warmth of the human body.
The eggs, or nits, are even more dependent on the host’s environment. They require the consistent, high temperature of the scalp to incubate and hatch successfully. A nit dislodged from the hair shaft and fallen onto a pillow cannot hatch. Therefore, the risk of starting a new infestation from a louse or nit found on a pillow is extremely low.
Cleaning and Treating Pillows and Bedding
Cleaning bedding is a recommended step to reduce the low risk of re-infestation, though the primary focus should remain on treating the head. All sheets, pillowcases, and clothing used by the infested person in the two days prior to treatment should be machine washed. The water temperature must be at least 130°F (54°C) to effectively kill the lice and the nits.
Following the wash cycle, drying the items on high heat for at least 15 to 20 minutes is necessary for decontamination. Items that cannot be washed or dried at high temperatures, such as certain pillows or stuffed animals, can be sealed in an airtight plastic bag. Leaving the sealed items for two weeks ensures that any live lice or nits will die from a lack of food and warmth. Vacuuming mattresses and upholstered furniture can help remove stray lice or hair strands with nits.