Head lice are tiny, wingless insects that live on the human scalp and feed on blood. These common parasites do not transmit disease, and their presence is not linked to poor hygiene. Understanding their appearance is key to identifying an infestation for timely management and prevention.
Identifying Adult Head Lice
Adult head lice are small, typically 2.5 to 3 millimeters long, comparable to a sesame seed. Their color can vary, often appearing grayish-white, tan, or brownish. After feeding, their bodies may take on a reddish hue. These insects have six legs, each equipped with hook-like claws, which they use to firmly grasp hair shafts.
Observing adult lice is challenging because they are fast-moving and avoid light. They crawl quickly through hair, not jumping or flying, making them difficult to spot without close inspection. Their small size and rapid movement often mean other signs of infestation are noticed before the adult lice themselves. A magnifying glass can be helpful for a more detailed view.
Recognizing Nits and Nymphs
Lice eggs, known as nits, are oval-shaped and tiny, about the size of a pinhead or a knot in a thread. They are typically yellowish-white, tan, or brown before hatching, and may appear clear or white once hatched and empty. Female lice lay these eggs very close to the scalp, usually within 6 millimeters of the hair shaft, gluing them firmly in place with a waterproof substance.
This strong attachment means nits cannot be easily flicked off hair, unlike dandruff, dry skin flakes, or hair product residue. If a speck can be brushed away, it is likely not a nit. Nymphs, immature lice, hatch from nits. Nymphs resemble smaller adult lice, initially translucent and pinhead-sized, gradually growing larger and darker as they mature.
Where to Find Them and What Else to Look For
When inspecting for head lice and nits, focus on specific scalp areas where they prefer to reside. These include hair behind the ears, near the nape of the neck, and along the hairline. These spots offer warmth and protection, creating an ideal environment. Live nits are typically found very close to the scalp, as they require body heat to hatch.
Other cues can indicate a possible infestation, even if live lice or nits are not immediately seen. Small red bumps or sores on the scalp, neck, or shoulders may be present from bites or scratching. Persistent scalp itching is a common symptom, though it might take weeks to develop after initial infestation. Small dark specks, possibly louse fecal matter, may also be noticed. Do not confuse these signs with other scalp conditions, such as dandruff or hair product buildup, which do not adhere to the hair shaft like nits.