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Lice - Head

Definition

  • A scalp infection with tiny gray bugs called lice
  • Lice lay many white eggs (nits) in the hair

Symptoms of Head Lice

  • The eggs are easier to see than the lice. Nits (eggs) are tiny white specks attached to hairs close to the scalp. Unlike dandruff or sand, nits can't be shaken off the hair shafts.
  • Best places to look for nits: behind the ears and along the hairline at the neck.
  • Itching of the scalp is the main symptom.
  • A scalp rash may be present. The back of the neck is the favorite area.

Cause

  • Lice are 1⁄16-inch (2 mm) long gray-colored bugs. They move quickly and are difficult to see.
  • They are the size of a sesame seed.
  • The lice feed on blood from the scalp. While the bug is sucking blood, some of its secretions get mixed in. Any scalp rash or bumps is the body's reaction to the bug's saliva.

Lifespan of Lice

  • The nits (eggs) hatch into lice in about 1 week.
  • Nits (eggs) that are over ½ inch (1 cm) from the scalp are empty egg cases. They are very white in color.
  • Off the scalp, nits (eggs) can't survive over 2 weeks.
  • Adult lice survive 3 weeks on the scalp or 24 hours off the scalp.

Transmission of Head Lice: Live Lice, Not Nits

  • Only live lice can give lice to another child.
  • Nits (lice eggs) cannot pass on lice. Nits are attached to the child's hair.

Lice Exposure: Low Risk for Getting It

  • Most children who are exposed to someone with head lice do not get them.
  • Lice cannot jump or fly. They can only crawl.
  • Lice are only passed to others by close head-to-head contact. Even then the risk is low.
  • Lice are rarely passed to others by sharing caps or combs.
  • Sleepovers and sleeping together only has a small risk.
  • Bed-sharing is the only reason the AAP recommends treating after exposure.
  • Most often, the spread of lice to others occurs at home, not school.

Barton Schmitt MD, FAAP
Disclaimer: this health information is for educational purposes only. You, the reader, assume full responsibility for how you choose to use it.
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