Source: CDC/Dr. Dennis D. Juranek (CDC Public Health Image Library)
Head lice are tiny insects that can be the size of a head of a pin up to about the size of a sesame seed (seeds found on a hamburger bun). They can be tan, brown, dark grey, or greyish-white.
Head lice crawl very quickly, which can make them hard to see. They don’t jump, fly, or swim.
Head lice live only on the human head and can make the scalp (the skin on the top of your head) itchy. They don't spread illness or disease. They can be found anywhere on the head, but especially behind the ears and the neck area at the base of the scalp. They don’t live on and aren’t spread by pets.
Adult head lice lay about 8 eggs (called nits) every day. The nits are stuck to the hair near the scalp. Nits are hard to see and can sometimes be mistaken for dandruff or hairspray droplets. After the nits hatch, their empty shell stays stuck to the hair.
You can’t get rid of lice with a hair brush or with a hair dryer.
It’s important to understand the life cycle of head lice to understand the treatment schedule for head lice.
Detection combing is an organized way to look for lice and nits in the hair, from the scalp outwards. If you only part the hair and look at the scalp, you may miss seeing lice or nits.
To do detection combing, you need:
If you do 1 detection comb and don’t find nits or any live lice, you don’t have to check again until your next regular weekly check.
If you do detection combing and you:
If you find something in the hair while combing and aren’t sure what it is, stick it on a piece of paper or clear sticky tape and show it to your healthcare provider. There may be other things in the hair that aren’t lice.
You only need to treat hair when you find live head lice. You do not need to treat the hair if you find only nits. If you have questions, ask your pharmacist.
Head lice shampoos, cream rinses, and sprays have been tested and are safe and effective treatments for head lice. You can buy them at any pharmacy and don’t need a prescription. If you’re not sure which one is best for your needs, talk to your pharmacist.
Read and follow the directions on the head lice shampoo, cream rinse, or spray. For the treatment to work, you
must follow the instructions exactly, including if the hair has to be wet or dry, and when to treat a second time.
You may have to buy more of the same product if you have to use it on longer hair. It’s important to use the correct amount of product each time. Using less of the product to make it go further will mean that the lice survive and more treatments will be needed.
The shampoo, cream rinse, or spray kills the live lice on the head but may not kill the nits.
While the nits don’t need to be removed from the hair, some people use a comb to remove nits after using lice treatment because they don’t like the look of nits in the hair.
A second treatment with head lice shampoo, cream rinse, or spray is almost always needed 7 to 10 days after the first treatment to kill newly hatched lice. If you’re not sure if a second treatment is needed, talk to your pharmacist.
Wash any items that were in contact with the head of the person who has lice, like combs, brushes, bedding, or hats. This includes the combs you used for detection combing.
To learn more about head lice, watch
head lice (video). You can also:
Current as of: July 25, 2023
Author: Public Health, Alberta Health Services
This material is not a substitute for the advice of a qualified health professional. This material is intended for general information only and is provided on an "as is", "where is" basis. Although reasonable efforts were made to confirm the accuracy of the information, Alberta Health Services does not make any representation or warranty, express, implied or statutory, as to the accuracy, reliability, completeness, applicability or fitness for a particular purpose of such information. Alberta Health Services expressly disclaims all liability for the use of these materials, and for any claims, actions, demands or suits arising from such use.