Lice are tiny greyish insects, about the size of a sesame seed and barely visible to the naked eye. They live on human heads, close to the root of the hair, and sometimes on the eyebrows. Lice can neither fly nor jump, and live about 20 to 30 days.
Lice are irritating but not dangerous. They do not spread diseases and are not the result of poor personal hygiene. Lice are most common in children in a school or day care setting.
Lice lay eggs called nits. Nits stick to hair strands and are difficult to remove. Live nits are a greyish white colour and look a bit like transparent, oily and swollen dandruff. They are usually located within 6 mm of the scalp and take 7 to 12 days to hatch.
Dead nits are white in colour and dry. They are most often located more than 6 mm from the scalp.
An itchy scalp is the main symptom of lice. The itchiness is caused by an allergic reaction to the saliva that the insect injects in the scalp to feed on blood. However, some people with lice do not have itching. An inspection of the head is the best way to find lice or nits. As they’re generally less than 10 to 20 live lice on the head, it is extremely important to conduct a thorough inspection.
Inspecting the head for lice
Good lighting is important in order to see lice moving because they run from light. A fine comb and, if possible, a magnifying glass, are perfect tools. Wet the hair to facilitate parting it with the fine comb.
To inspect the head:
- Part the hair into thin sections about the width of the nit comb. If the hair is very long, split in 2 cm locks.
- Comb the hair from the roots close to the scalp and through to the tips, one section at a time.
- Inspect the hair by sections from one side of the scalp to the other, and from the hairline to the back of the neck, paying particular attention to the back of the ears and to the neck.
- If you find lice or nits on the comb, end the inspection and apply anti-louse treatment as soon as possible. See the Treatments section for products to use.
Repeat inspection of the head as follows:
- At least once a week after washing the hair, especially during back-to-school period
- Daily if people in your surroundings have lice
- As soon as the scalp feels itchy
Do not forget to wash your hands after each inspection.
There is no treatment for the prevention of lice, which means that there is no use in treating people with neither lice nor live nits.
Treatment is most effective if everyone with lice or live nits is treated on the same day. It may be difficult to determine whether the nits are dead or alive. If in doubt, consult a healthcare professional before starting treatment.
Lice and nits resist ordinary shampoos but can be eliminated with special over-the-counter treatment. It’s important to apply one of the recommended treatments as soon as you discover lice or live nits on the scalp.
There are 2 types of treatments:
- 2-step application treatments that rid of lice and nits
- 3-step application treatments that rid of lice but have little or no effect on nits
Here are recommended products:
2-step application treatments:
- NYDA® (recommended for people 2 years old and over)
- Kwellada-P® 1% or Nix® 1% (recommended for people 2 years old and over)
- Pronto® or R & C® (recommended for children less than 2 years old)
For pregnant or breastfeeding women:
- Best products: Kwellada-P® 1% or Nix® 1%
- Also recommended: Pronto® or R & C®
Note: Even if treatment against lice is considered safe for pregnant or breastfeeding women and their children, they should consult a doctor before any treatment.
3-step application treatments:
- Zap® or Resultz® (recommended for people 2 years old and over)
Kwellada-P® 1% and Nix® 1% hair treatment products are less effective if you use a conditioner, silicone-based products or vinegar in your hair. Do not use these products shortly before a treatment with Kwellada-P® 1% and Nix® 1%, and wait 2 days after the treatment before using them. For more information, talk to a pharmacist or contact Info-Santé 811.
It is strongly discouraged to use products for pets.
Apply product following instructions on the product label. Then dry the hair with a towel or dryer.
- 9 days after first application if using a 2-step treatment
- 7 days after first application and 7 days after second application if using a 3-step treatment
Note: Application of anti-louse products may cause itchiness or a light burning sensation of the scalp.
You must also inspect the head and remove lice and nits with a fine comb on the second, eleventh and seventeenth day after first application of treatment. See the Inspecting the head for lice and Removing nits sections for further instructions.
Live lice 17 days after starting of the treatment
If you find live lice 17 days after the 1st application, start over with another product containing different active ingredients.
Avoid using one product after another with similar active ingredients. This may cause the lice to become resistant and reduce the effectiveness of a 2nd treatment.
As such, if the 1st product you used was one of the following:
- Kwellada-P® 1%
- Nix® 1%
- R & C®
do a 2nd treatment with one of these products:
There are no restrictions regarding use of other products, though you must definitely use a different product for a 2nd treatment.
For info on what 2nd treatment to use on children less than 2 years old or for pregnant or breastfeeding women, ask a doctor, pharmacist or nurse.
After the use of anti-louse treatment, it is important to remove live nits from the hair in order to avoid the hatching of new lice.
To remove the nits more easily, apply a humid towel to the scalp for at least 30 minutes. Then untangle your hair with a comb.
Make sure you have a fine comb, good lighting and have easy access to hot water so that you can rinse the comb with each comb-through. If possible, also use a magnifying glass to help you.
To remove nits:
- Part the hair into thin sections about the width of the fine comb. If the hair is very long, split in 2 cm locks
- Comb through each section of the hair starting from as close to the scalp as possible until the hair tips
- Inspect the hair by sections from one side of the scalp to the other, and from the hairline to the back of the neck, paying particular attention to the back of the ears and the neck
- Rinse comb with hot water after every section to remove nits stuck to it. Remove stubborn nits with your nails or tweezers. Catch the nits and slide them off the hair
Wash your hands when finished removing nits.
Removing nits and using anti-louse treatment increase your chances of getting rid of lice and nits.
If you find lice or nits on the eyebrows, apply a thick coat of petroleum jelly (Vaseline® or Lacri-lube®). This stops the lice from moving and suffocates nits, preventing them from hatching. Remove the lice and nits with your nails or tweezers. Repeat procedure 2 to 4 times over the course of a week.
Cleaning personal effects
It is unlikely that lice is transmitted through personal effects (bedding, combs, hairbrushes, hats, caps, etc.). However, you can treat these objects as follows:
- Soak personal effects in undiluted anti-louse shampoo for 5 to 10 minutes
- Soak personal effects in hot water with a temperature of about 65 ˚C for 5 to 10 minutes
- Put clothing items in dryer on hot setting for 20 minutes
- Dry clean the clothes
- Store personnel effects in an airtight plastic bag for 10 days, which is the average time for nits to hatch
Use a vacuum to clean carpets and sofas.
It is strongly discouraged that you spray your house or furniture with insecticide. Insecticides are not only ineffective in eliminating lice, they can also be harmful to your health and that of your pets.
Should you have questions regarding the effectiveness of a treatment, ask a doctor, pharmacist or nurse, or contact Info-Santé 811.
Lice spread easily from one head to another when there is hair contact, such as when two people hug. However, it is harder to spread through contact with objects such as hats, combs, hairbrushes, glasses, bed linens, pillowcases, sofa covers or carpets.
Lice do not live on pets, they only feed on human blood. Pets therefore, do not play a role in spreading lice.
Protection and prevention
There are no prevention treatments for lice. However, it is possible to limit or avoid the spread of them by identifying and promptly treating people with lice. If you or anyone in your family gets lice, immediately tell everyone with whom you have been in direct contact, including your children’s school or day-care staff. This way, others that may have caught lice are quickly identified and treated.
- Attach long hair
- Remind children to:
- Avoid coming into head to head contact
- Store their hats, caps or scarves in the sleeves of their coat
- Not to share personal effects such as combs, brushes and hats
- Regularly inspect the heads of everyone in your family with a nit comb:
- At least once a week after washing hair, especially during back-to-school period
- Daily if someone in the surrounding has lice
- As soon as there is a case of itchy scalp
Last update: August 22, 2018