Head Lice Facts

Frequently Asked Questions About Head Lice

What are head lice?

The head louse, or Pediculus human capitis, is a parasitic insect that can be found on the head of human beings. Head lice feed on human blood several times a day and need to live close to the scalp to maintain their body temperature.

What is the life cycle of lice? How long do lice live? What do lice look like?

The life cycle of the head louse has three stages: nit, nymph, and adult. The life cycle of a single louse from egg to mature adult capable of laying eggs or reproducing is about 21 days.











A louse has a life expectancy of 30 days, and a female can be fertile for 20-23 days. Once the louse becomes an adult and mates, she can lay 6-10 nits per day – or more than 200 in her lifetime.

Head Lice NitNits/Eggs:

Head lice eggs are called nits. Nits are laid by the adult female louse and are found on the first one to one 1/2 inches of hair. They are located close to the scalp because they require body heat for incubation.

Size – 0.8mm by 0.3mm
Shape – Oval
Color – Yellow to white
Location – Within 6mm of the scalp
Duration – Nits take 7 – 10 days to hatch.

Adult Head LiceNymphs:
When an egg hatches, it releases a nymph. The nit shell stays attached to the hair and turns a dull yellow color. The nymph looks like an adult louse but is smaller. As the nymph grows, it molts out of its exoskeleton three times before it becomes an adult.

Size – Variable but about the size of a pinhead
Shape – Same shape as the adult louse
Color – Yellow to rust-colored
Location – Close to the scalp, especially behind the ears and at the neckline
Duration – Nymphs become adults after about 8-12 days

The adult louse feeds about five times a day by piercing the skin with its claws, injecting irritating saliva, and sucking blood. Lice do not become engorged like ticks, but their color changes to a rust color after feeding. Head lice hold onto the hair with hook-like claws found at the end of each of their six legs. Adult lice are active and can travel quickly.

Size – The size of a pinhead – The female louse is larger than the male.
Shape – Oval with six legs and claws at the end of each leg
Color – Rust
Location – Close to the scalp, especially behind the ears and at the neckline
Duration – Adult lice can live up to 30 days on a person’s head
Reproduction – An adult female can lay up 6-10 eggs a day.

Does Lice Shampoo Work?

RID, Nix and other lice shampoos ONLY kill adult lice and adolescent nymphs. These shampoos work by attacking the bug’s central nervous system. Because baby lice or “nymphs” have not yet developed a central nervous system, they cannot be killed by pesticides.

This leads to a common pattern of lice suppression and resurgence when families use lice shampoos and prescription treatments.

What does that mean? Since lice shampoos only kill live bugs and not their eggs, it’s up to parents to comb out every single lice egg. If just one or two are left behind, it will take about 3 weeks for those left behind eggs to hatch, starting a new cycle of lice infestation.

During those weeks, parents think they have the problem under control, not knowing those eggs are developing into live bugs. This is also a common reason lice are spread to other family members and classmates. In other words, the lice aren’t necessarily coming back, they were never completely gone in the first place.

MANY families come to us after using multiple rounds of lice shampoos without success. READ MORE HERE about recurring head lice and what you can do about it.

What are the symptoms of lice?

Common Symptoms of Lice are:

  1. Scalp itching
  2. Sensation of something moving in the hair
  3. Red or pustular sores on the scalp caused by scratching
  4. Swollen lymph nodes in the front and back of the neck

How do I know if I have lice?

Head lice are most commonly found on the scalp, behind the ears and near the neckline at the base of the head. An allergic reaction to the bites causes the itching; only about 50% of people with head lice experience itching. Misdiagnosis of head lice is common, though.

The best way to confirm an active case of head lice is by finding a live nymph or adult louse on the scalp or hair. Adult and nymphal lice are very small, move quickly, and avoid light, so they may be difficult to find. Using a fine toothed louse comb helps in correctly diagnosing head lice.

If you have lice, you will have nits/eggs in your hair. If you have nits, they have been laid by live lice. Nits do not spontaneously appear and are not themselves contagious.

Viable nits are usually located within 1/4 inch of the scalp. The nits are small teardrop-shaped eggs that show up differently in different colored hair. The darker your hair, the lighter the nits will appear. The lighter your hair, the more closely the nits will blend in with your hair. It is more challenging to find the nits on lighter hair colors.

Nits are essentially “glued” into the hair. They will not move without being pulled with some force with your fingernails. Once you get them to budge, they will only move up and down the hair shaft (rather like a bead on a bracelet.) If you pull it all the way off and lay it on a white napkin or tissue, it will have a brownish tint to it.

Dandruff will not be “stuck” in the hair, and will move if you brush it with your finger or blow on it lightly.

How do you get lice?

Head lice come from other people who have head lice. Head lice are human parasites that have been in existence for tens of thousands of years. Dried up head lice and their eggs have been found on the hair of Egyptian mummies. They have adapted to be extremely good survivors.

Head lice are most commonly spread from direct head-to-head contact (hugging, whispering, sharing a pillow, etc.) Less commonly, they can also be spread by sharing brushes, combs, hats, scarves, hoodies, etc. Lice do not live more than 48 hours off of their host.

Do lice jump?

No! Head lice do not jump or fly. They are good crawlers, however, and will readily move from one host to another.

Can dogs get lice?

No. Head lice cannot live on pets of any kind. Head lice are human parasites and can only live on human heads.

Where does lice come from? Who is at risk of getting head lice?

Everyone is at risk. Anyone having contact with an infected person can get head lice. Rest assured, if you have lice it does NOT mean you are dirty! In fact, they prefer their hosts to be quite clean.

Can lice make you sick?

Head lice are inconvenient but not dangerous. They do not carry any sort of disease.

What do lice eat?

Lice spend their entire life on the human head and feed exclusively on human blood 5-6 times each day by biting the scalp, which is what causes some people to feel itchy.

Do lice have wings?


How big are lice?

Lice range in size from 2mm to 4mm, or about the size of a sesame seed.

Size of Head Lice

Can you see lice?

Yes. Lice are bigger than many people expect! They are not, as some people believe, “microcopic” or “invisible.” They can be seen with the naked eye.

Are the treatments at Pediatric Hair Solutions covered by insurance?

As a medically owned and operated head lice treatment center, our treatments are covered by most insurance plans.

We also have a 100% reimbursement rate with Flexible Spending Accounts (FSA) and Health Savings Accounts (HSA).

For your convenience, we provide you with the appropriate form including diagnostic and procedure codes needed to submit claims for reimbursement.

Your pre-filled CMS 1500 form to file with your insurance provider will be included with your discharge papers. If you prefer, you can call your healthcare insurer prior to your appointment to confirm insurance coverage.

If your claim is denied, you may request a letter of medical necessity written by the Medical Director at Pediatric Hair Solutions, Dr. John Fassler.

How do I treat my home for lice? Can lice live on hard surfaces?

It is important to remember that the infestation is on the head – not in the home! It is necessary to clean your house thoroughly once a lice infestation has been discovered. However, we have found that most parents’ instincts are to do far more than is necessary!

The first thing to remember is head lice can not live off the human host for more than 48 hours. Also, lice do not have “feet” and can not travel well an smooth hard surfaces. Lice can not jump or fly. Nits/eggs need to be in a warm, dark, moist place to incubate. Please do not use a pesticide spray on furniture. Remember, lice are resistant and the use of pesticides can have harmful side effects.

  • Clean all bed and bath linens that have come in contact with affected individuals. Placeclothing, linens, etc in the dryer on high heat for 30-40 minutes. Do the same with clothing andouterwear worn within 48 hours.
  • Vacuum carseats, carpets, floors, mattresses, and furniture where there has been contactwithin last 48 hours.
  • All hair brushes and accessories need to be placed in baggies and put in the freezer for 48hours and then washed thoroughly in hot soapy water. Label these items in the future so they are notshared.
    Sports and bike helmets go into freezer for 48 hours.
  • There are many items that cannot be placed in the dryer, but must also be treated. Isolationis the best method for dealing with these items, including stuffed animals, pillows, or headphones. Youshould expect these items to be out of commission for at least 48 hours.

This process only needs to be done one time on day of treatment with the FloSonix device.

How Do Lice spread?

Head lice can be spread by direct contact with the head or hair of an infested person. The adult louse can survive for up to 1-2 days without feeding on the scalp; therefore lice can be found on objects that have been in contact with an infested person.

How can I prevent the spread of head lice?

Avoid head to head contact during play, sleepovers, or other activities at home, school, and elsewhere. Do not share, combs, brushes, or towels used by an infested person. Do not share clothing such as hats, scarves, coats, hair ribbons, or barrettes. Machine wash and dry clothing, bed linens, and other items that an infested person used or wore during the previous two days using a high heat drying cycle. Do not use fumigant sprays or fogs; they are not necessary to control head lice and can be toxic if inhaled or absorbed through the skin.

Head Lice Treatment Comparison Chart

We recommend our 3-Step Head Lice Treatment, which includes at-home pre-treatment, in-clinic professional device treatment, and at-home post-treatment. This combination of treatments has a 100% success rate! For more details please visit our Head Lice Treatment Services page.

*For a complete and “eye-opening” chart showing how our treatment works vs. Sklice vs. over-the-counter/other topical treatments vs. nit picking and combing, please click here (PDF document).