Facts of Lice


What are head lice?

The head louse, or Pediculus humanus capitis, is a parasitic insect that can be found on the head, eyebrows, and eyelashes of people. Head lice feed on human blood several time a day and live close to the human scalp. Head lice are not known to spread disease.

Forms of Head Lice

Head lice has three forms – the egg (also called a nit), the nymph, and the adult.

Eggs (nits)

  • Eggs do NOT hatch when they are off the head and they Do NOT re-attach
  • Eggs are translucent (They appear brown when wiped on a wet paper towel)
  • Eggs are microscopic when they are first laid so getting rid of lice is always a process (this is why one treatment will not eradicate lice; you can’t get out what you can’t see)
  • Eggs attach to the hair and do not fall off like dandruff

Bugs (louse, nymph):

  • You can only get lice from a bug NOT eggs so eggs are NOT contagious
  • Bugs can only crawl they CANNOT jump, fly, dig, or burrow
  • Bugs like CLEAN hair
  • Bugs can lay up to 10 eggs per day and need to mate in order to do so
  • Bugs can live off your body up to 36 hours
  • Bugs can hold their breath up to 6 hours
  • Bugs do not carry disease they are just annoying
  • Bugs do not like light so most people with short or thin hair are less likely to get it because they can’t hide
  • Bugs live about 30 days


What do head lice look like?

Size of head lice compared to a penny
Actual size of the three lice forms compared to a penny. (CDC Photo)
Illustration of a head lice egg
Egg on hair shaft. (CDC Photo)
Head lice nymph
Nymph (CDC Photo)
Adult head louse
Adult (CDC Photo)


What are the signs and symptoms of head lice infestation?

  • Tickling feeling of something moving in the hair.
  • Itching, caused by an allergic reaction to the bites of the head louse.
  • Irritability and difficulty sleeping; head lice are most active in the dark.
  • Sores on the head caused by scratching. These sores can sometimes become infected with bacteria found on the person’s skin.