What Do Head Lice and Nits Look Like?

Head Lice

Head lice are parasitic insects found most often behind the ears and near the neckline at the back of the neck. The medical term for head lice infestation is Pediculus humanus capitis. There are 10 - 12 million reported cases of head lice in the United States every year. Head-louse infestation is most frequent on children aged 3-10 and their families. Females get head lice more often than males, and infestation in the black ethnicity are rare.

Head Lice Life Cycle

The life cycle of the head louse has three stages:

  • Nit
  • Nymph
  • Adult

A single louse will live for about 30 days on a human host. They can survive for up to 48 hours off a human host.

Nits:

Nits are head lice eggs. They are hard to see and are often mistaken for dandruff or droplets of hairspray. Nits are found firmly attached to the hair shaft. They are located close to the scalp because they require body heat for incubation. Nits take about 7-10 days to hatch.

Nit description:

  • Size - 0.8mm by 0.3mm
  • Shape - Oval
  • Color - Yellow to white
  • Location - Within 6 mm of the scalp
  • Life Span - Nits take 7 - 10 days to hatch

Nymphs:

This Nymph is emerging from its shell

Nits hatch into Nymphs. The nit shell stays attached to the hair shaft and turns a dull yellow. The nymph looks like an adult louse but smaller. The nymph will molt out of its exoskeleton 3 times before it becomes an adult.

Nymph characteristics:

  • Size - About the size of a pinhead
  • Shape - Same shape as the adult louse* Shape - Oval
  • Color - Yellow to rust-colored
  • Location - Close to the scalp, especially behind the ears and at the neckline
  • Life Span - Nymphs become adults after about 7 days

Adult Head Lice Pictures


Adult lice feed about 5 times each day. The mouth contains two retractable, needle-like tubes that pierce the scalp. Salivary juices are injected into the scalp to prevent blood from clotting, and then the lice feed happily, sucking blood through these same tubes.

Their color changes from grayish white to a rust color after feeding. Head lice hold onto the hair with hook-like claws found at the end of each of their 6 legs. Adult lice are very active and can travel extremely well.

Adult head lice characteristics:

  • Size - The size of a pinhead. The female louse is larger than the male.
  • Shape - Oval with 6 legs and claws at the end of each leg
  • Color - grayish white or Rust after they feed
  • Location - Close to the scalp, mostly behind the ears and at the neckline
  • Life Span - Adult lice can live up to 30 days on a person's head, and 48 hours off
  • Reproduction - An adult female will lay 3-10 nits per day

More Head Lice Pictures:

Head Lice Pictures