- Diseases, Disorders & Conditions
Battling a Prehistoric Menace- Head Lice in Children
What are head lice ?
Head lice, (pediculus humanus capitis), are small, wingless insects that are approximately 2.5-3.5 millimetres in length. These tiny parasites live, eat and breed on the hair and skin of the human scalp. Head lice are often mistakenly called 'nits' but this actually refers to the eggs laid by the lice. Head lice are one of three types harboured by humans- The other two are body lice and pubic lice. Head lice infestations appear to be on the rise as these parasites continue to outwit their human hosts.
Head lice most likely co-evolved with people and have actually been recovered from prehistoric mummies. As such, lice are now used in the field of archeogenetics (the study of the human past through DNA). The mitrochondrial DNA of female lice can be isolated and used to determine migration patterns of ancient humans. These tiny, wingless insects are also excellent examples of evolution. Over time, their six powerful legs have developed to grasp hair shafts and take up residence on their host's scalp.
Head live do not spread disease but simply live among human hairs and feed on tiny amounts of human blood drawn from the scalp. The insects cannot actually jump or fly but rather roam the scalp by moving between hair shafts with their strong claws. Female lice lay around six to eight eggs a day close to the scalp which is their food source. These eggs appear as small, whitish flecks, often seen behind the ears and towards the nape of the neck. Appearance of these nits is often the first tell tale sign your child has head lice.Once laid, these eggs hatch within seven to ten days, thus beginning the cycle of infestation.
A magnified image of head lice.
How are head lice spread ?
As head lice are unable to fly or jump, they must come in to close contact with another host in order to spread. A mature female louse can lay three-four eggs per day, multiplying to over one hundred per month. Although tiny, the average speed movement of a louse has been calculated at at 3.75 inches per second. This is equivalent to 18.75 feet in one hour and approximately 450 feet per day- Over the length of a entire football field ! If your child sits or lies next to a person with head lice there is a high chance they will become infected. This explains why head lice infestations occur most frequently in school children because in these types of environments children tend to be in close personal contact. Sharing a hairbrush, comb or hat can also lead to cross infestation. Head lice will spread very quickly spread through a whole class room so it is very important to diagnose and treat an infestation as quickly as possible.
Unfortunately there is still a great deal of misunderstanding and stigma attached to head lice and it can often be quite a distressing experience dealing with a lice infestation. However, head lice are referred to as 'equal opportunity' parasites as they do not discriminate on the basis of gender, hair colour, ethnicity or socio-economic status. Approximately ten-twelve million Americans will become infected with lice on a yearly basis. A head lice infestation has nothing to do with your child's personal hygiene or the cleanliness of your home.
How do I know if my child has head lice ?
The most common sympton is an itchy scalp so if you see you child itiching their head, particularly around the ears and the nape of the neck, check to see if there are any live lice or eggs present. This itchiness is actually a reaction to the saliva the lice excrete whilst feeding on the scalp. Children may also experience a rather uncomfortable feeling of something crawling over their head. However, there are some cases where a child has no obvious symptoms so it is important to check their head very carefully to see if lice or nits are present, especially if there has been a report of an outbreak in the class.
How do I treat my child ?
Fortunately, once detected, a head lice infestation is reasonably easy to treat and there are several ways you can do this:
1. Wet comb-conditioner technique to detect and remove.
This technique involves applying a thick layer of conditioner to your child's hair and then combing the conditioner through the hair with a fine tooth comb. This will remove any lice and eggs but it needs to be repeated daily for around ten to fourteen days until no lice or eggs are found. This is a reasonably painstaking process, hence the term 'nit picking', and it only has a forty percent success rate. Petroleum jelly, olive oil and mayonnaise are also used to suffocate the lice before combing them out but the success of these treatments is questionable.
2. Over the counter shampoos and lotions.
There are many chemical treatments in the form of shampoos, lotions and mousses that you can buy over the counter. Unfortunately there is a high degree of resistance to many of these commercial lice treatments and none can claim to have a 100 % success rate in ridding your child of lice and preventing a re-infestation. As such, you may need to try several products before being satisfied with the results. These chemical treatments are essentially insecticides that have been approved for human use. The active ingredients in these treatments include permethrin, pyrethrin, marathon and bioallethrin/piperonyl butoxide.
These products are designed to be applied to hair once lice are detected and then a follow up treatment is normally required seven-ten days after to kill any lice that may have hatched. If your child is under the age of two you should not use medicated lice treatments on them.
3. Natural treatments
If the idea of applying an insecticide to your child's scalp concerns you, there are several herbal treatments available that are showing some promise but, again, none can claim to have a 100 % success rate. These treatments use a combination of herbal extracts such as tea tree, eucalyptus, lavender and peppermint oils and are designed to either kill head lice or repel them.
How can I prevent reinfestation
Fortunately head lice are rarely transferred through clothing, hats, furniture or bedding and they can only survive up to a day away from the human host. Lice do not breed on animals, bedding, furniture, carpets, clothes or soft toys as their life cycle must be completed on the human head. As such, there is no need to spend a great deal of time and effort trying to rid your house of lice.
However, if you want to be confident your home is completely 'lice free', it is recommended you vacuum carpets and any furniture wash all bed linen and clothing that has recently been worn by anyone in the home with lice in very hot water, ( at least 130 degrees Fahrenheit, 54.4 Celsius), followed by twenty minutes in the hot cycle of the dryer. For items that can't be washed, (such as hats and soft toys), place them in a sealed plastic bag for three days or in the freezer for a couple of hours.
Keep long hair tied back or in plaits, especially whilst at school. Carry out weekly hair and scalp checks when lice are present at school and do not share hats, hairbrushes, combs and pillows. There is some evidence to suggest applying hair spray prevents lice attaching to the hair shaft and spraying a mixture of water and tea tree, peppermint or lavender oil to the hair may act as a deterrent.