Head Lice Heads Up: How to Spot and Get Rid of Unwanted Visitors

I distinctly remember the day my daughter, then in third grade, solemnly (but with an dab of schadenfreude) announced on the way home from school, “The whole first-grade has lice.” Like many parents before and after me, upon hearing the word ‘lice,’ my heart stopped for a split second and I immediately felt itchy. Of course, there was no real reason to panic. Aside from being a nuisance, and somewhat gross, head lice don’t pose a significant health risk.

Head lice are tiny, equal opportunity marauders. This is the good news and the bad news. These strawberry-seed-sized insects feed on blood from people’s scalps, where they also lay their eggs. A colony or infestation of head lice is itchy and can result in a secondary infection from scratching the bites but is not a sign of poor hygiene. The common head louse, or Pediculus humanus capitis, if you want to use the Latin name, also thankfully is not a disease spreader. 

So yes, a case of lice is a disturbing nuisance, but not a health catastrophe. 

Also in the good news category, lice cannot hop or fly. They can only crawl and are spread by direct contact with the hairs of a person with lice. Anyone who comes in contact with a person who has lice is at risk, but transmission from hats, scarves, combs, brushes or other personal items is less risky.  

Lice spread from person to person and are most common among school aged children. Think about how kids interact, often huddled up head-to-head when working or playing at school or daycare. It’s estimated that between six and 12 million children between the ages of 3 and 11 get head lice each year in the United States. 

Kids get lice at school, slumber parties, sporting events, on playgrounds and at camp. Siblings give lice to each other. Head lice can’t be transmitted to (or from) dogs and cats. Head lice are not likely to be spread in a swimming pool, although lice can survive up to several hours under water.

How to spot lice

There are three stages in a louse’s life: the egg (called a nit), the nymph (baby louse) and the adult. Nits (lice eggs) are laid by the mother louse on the scalp, at the base of the hair shaft. They adhere to the hair and are small, yellow or white oval shapes, easy to confuse with dandruff and hard to pick off of the hair. They take 8 or 9 days to hatch. If you see a nit that is more than ¼ inch from the scalp, it’s probably an empty shell that has already hatched.

A nymph is what comes out of a nit. It’s a small, immature louse, which must eat blood to survive. Nymphs become full-fledged adult lice in about 9-12 days.

Adult lice are the size of a sesame or strawberry seed, are light gray-white to brownish in color and have six legs. On your head, an adult louse will live about a month. Off your head it will die in a day or two. Adults, like nymphs, must feed on blood. Females are a little bigger than males and lay six to ten eggs per day. You may of may not want to do the math. That’s 180 to 300 eggs per month per adult female louse.

What having lice feels like

Itchy. Also, itchy. You might notice a feeling of tickling movement on your scalp. That’s the lice on the move. You might find it hard to sleep because lice are most active in the dark. If you’ve scratched lice bites, you may develop sores on your scalp which can become infected and painful. Lice like to congregate behind the ears and at the back of your head, near your neck. Rarely, lice or nits may be present in eyebrows or eye lashes.

How to get rid of lice, according to CDC guidelines:

Treatment requires using an Over-the-counter (OTC) or prescription medication. Follow these treatment steps:

1. Before applying treatment, it may be helpful to remove clothing that can become wet or stained during treatment.
2. Apply lice medicine, also called pediculicide, according to the instructions contained in the box or printed on the label. If the infested person has very long hair (longer than shoulder length), it may be necessary to use a second bottle. Pay special attention to instructions on the label or in the box regarding how long the medication should be left on the hair and how it should be washed out. 
3. Have the infested person put on clean clothing after treatment. 
4. If a few live lice are still found 8–12 hours after treatment, but are moving more slowly than before, do not retreat. The medicine may take longer to kill all the lice. Comb dead and any remaining live lice out of the hair using a fine–toothed nit comb. 
5. If, after 8–12 hours of treatment, no dead lice are found and lice seem as active as before, the medicine may not be working. Do not retreat until speaking with your health care provider; a different pediculicide may be necessary. If your health care provider recommends a different pediculicide, carefully follow the treatment instructions contained in the box or printed on the label. 
6. Nit (head lice egg) combs, often found in lice medicine packages, should be used to comb nits and lice from the hair shaft. Many flea combs made for cats and dogs are also effective. 
7. After each treatment, checking the hair and combing with a nit comb to remove nits and lice every 2–3 days may decrease the chance of self–reinfestation. Continue to check for 2–3 weeks to be sure all lice and nits are gone. Nit removal is not needed when treating with spinosad topical suspension. 
8. Retreatment is meant to kill any surviving hatched lice before they produce new eggs. For some drugs, retreatment is recommended routinely about a week after the first treatment (7–9 days, depending on the drug) and for others only if crawling lice are seen during this period. Retreatment with lindane shampoo is not recommended.