Head lice are tiny insects that live in hair. Nits are the empty egg cases attached to hair that head lice hatch from. Head lice are a common problem, particularly in school children aged 4-11. They're largely harmless, but can live in the hair for a long time if not treated and can be irritating and frustrating to deal with.
How to spot head lice
Head lice can be difficult to spot, even when the head is closely inspected. They are very small whitish or grey-brown insects that range from the size of a pinhead to the size of a sesame seed.
The only way to be sure someone has head lice is to find a live louse by combing their hair with a special fine-toothed comb. This is called detection combing. Less reliable signs of head lice include:
- small
white eggs or nits (egg cases) in the hair behind the ears or at back
of the neck – see image above
- an
itchy scalp
- a
rash on the back of the neck
- feeling
as though something is moving in the hair.
How to get rid of head lice and nits
Treatments to get rid of head lice are available to
buy from pharmacies, supermarkets and online. You don't usually need to see
your doctor/ GP. The main treatments are:
- lotions
or sprays that kill head lice – these can be very effective, but
some aren't suitable for pregnant or breastfeeding women, or for children
under two
- removing
head lice with a specially designed comb – this is suitable for
everyone and relatively inexpensive, but needs to be repeated several
times and can take a long time to do thoroughly.
A pharmacist can advise you about
the treatments available if you are not sure which is best for you or your
child. Make sure you carefully follow the instructions
that come with the treatment you choose.
How you get head lice
Head lice are spread by direct head to head contact. They climb from one person's hair to another's. Head lice:
- cannot
fly, jump or swim
- are
very unlikely to be spread by objects such as hats, combs and pillows
- don't
have a preference for dirty, clean, short or long hair
- only
affect people and can't be caught from animals.
Once detached from the hair, head lice will usually
die within 12-24 hours.
Preventing head lice
Schematic diagram showing the life cycle of head lice.
Preventing head lice
It is very difficult to prevent head lice. You may want to consider regular detection combing – for example, on a weekly basis – if you are concerned about your children or yourself. Lotions and sprays don't prevent head lice and should only be used if a live louse has been found in your or your child's hair.
Staying off work or school and washing clothing and
bedding on a hot wash is unnecessary, as it's unlikely to help prevent the
spread of head lice.
How to detect head lice
The only way to be
certain that you or your child has head lice is to find a live louse. Spotting head lice in hair can be very difficult,
so it's best to try to comb them out with a detection comb.
Detection combs are special fine-toothed plastic
combs that you can buy from your local pharmacy, supermarket or online.
A comb with flat-faced teeth and a tooth spacing of 0.2-0.3mm is best.
Detection combing can be carried out on dry or wet hair. Dry combing takes less time, but wet combing is more accurate because washing with conditioner stops head lice moving.
Wet detection combing
To use the wet detection method:
- Wash the
hair with ordinary shampoo and apply plenty of conditioner.
- Use
an ordinary, wide-toothed comb to straighten and untangle the hair.
- Once
the comb moves freely through the hair without dragging, switch to the
louse detection comb.
- Make
sure the teeth of the comb slot into the hair at the roots, with the edge
of the teeth lightly touching the scalp.
- Draw
the comb down from the roots to the ends of the hair with every stroke,
and check the comb for lice each time – remove lice by wiping the
comb with tissue paper or rinsing it.
- Work
through the hair, section by section, so that the whole head of hair is
combed through.
- Do this at least twice to help ensure you haven't missed any areas and continue until you find no more lice.
If you find head lice, you should check the rest
of your family. Treat everyone found to have head lice on the same day.
There are different commercially available products which can be used for the effective treatment of head lice.
Dry detection combing
To use the dry detection method:
- Use
an ordinary, wide-toothed comb to straighten and untangle the hair.
- Once
the comb moves freely through the hair without dragging, switch to the
louse detection comb.
- Make
sure the teeth of the comb slot into the hair at the roots, with the edge
of the teeth lightly touching the scalp.
- Draw
the comb down from the crown to the ends of the hair with every stroke.
- Look for
lice as the comb is drawn through the hair. If you see a louse, trap it
against the face of the comb with your thumb to stop if being repelled by
static electricity.
- Comb
each section of hair three or four times before moving on to the next
section, until the whole head has been combed through.
If you find head lice, you should check the rest
of your family. Treat everyone found to have head lice on the same day.
How to get rid of head lice and nits
Treatments to get rid of
head lice are available to buy from pharmacies, supermarkets and online. The main treatments are:
- Lotions and sprays
- Wet combing
Everyone with head lice in your household should be
treated on the same day. If a treatment does not work the first
time, you can try it again, try a different treatment, or get
advice from your school nurse, health visitor, pharmacist or GP.
Lotions and sprays
There are several different products that can be applied to the scalp and hair to kill head lice, including:
- dimeticone
4% lotion or lotion spray – applied and left for 8 hours (usually
overnight)
- dimeticone
4% spray gel – applied and left for 15 minutes
- mineral
oil and dimeticone spray – applied and left for 15 minutes
- isopropyl
myristate and cyclomethicone solution – applied and left for 5-10 minutes.
Some treatments need be done twice – seven days
apart – to make sure any newly hatched lice are killed. Detection combing should usually be
done two or three days after finishing treatment, and again another seven days
after that, to check for any live head lice.
Always check the pack or leaflet to see if a
product is suitable for you, particularly if you're pregnant or breastfeeding,
or your child has head lice and is less than two years of age. Your pharmacist can recommend a suitable treatment
and advise you how to use it correctly if necessary.
Wet combing
Wet combing involves removing head lice with a special fine-toothed comb. It is suitable for everyone and is relatively inexpensive.
A number of lice removal combs are available to
buy. Combs with flat-faced teeth spaced 0.2-0.3mm apart are best for removing
head lice, although combs with smaller gaps can be used to remove eggs and nits
(egg cases) after treatment.
The comb may come with instructions outlining how to use it. A commonly used method is described below:
- Wash
the hair with ordinary shampoo and apply plenty of conditioner.
- Use
an ordinary, wide-toothed comb to straighten and untangle the hair.
- Once
the comb moves freely through the hair without dragging, switch to the
louse detection comb.
- Make
sure the teeth of the comb slot into the hair at the roots, with the edge
of the teeth lightly touching the scalp.
- Draw
the comb down from the roots to the ends of the hair with every stroke,
and check the comb for lice each time – remove lice by wiping the comb
with tissue paper or rinsing it.
- Work
through the hair, section by section, so that the whole head of hair is
combed through.
- Do
this at least twice to help ensure you haven't missed any areas, until no
more lice are found.
Repeat this procedure on days five, nine and
13. Detection combing should be done on
day 17, to check for any live head lice.
Treatments not recommended
The following treatments are not recommended because they're unlikely to be effective:
- products
containing permethrin
- head
lice "repellents"
- electric
head lice combs
- tree
and plant oil treatments, such as tea tree oil, eucalyptus oil, and
lavender oil
- herbal
remedies.
There is also no need to stay off work or school or
wash clothing and laundry on a hot wash, as this is unlikely to be useful.
Source: NHS Choices