The tiny grey bugs called head lice that lay their even tinier white eggs (called nits) on hair shafts cause distress way out of proportion to their size! Many a distressed parent calls their pediatrician or runs into the doctor’s office asking for help with this common problem (6 to 12 million infestations a year in the United States). Let’s see if we can save you a trip.
Most importantly, lice do not spread disease. They are in this sense not a health risk to your child. They are also not a sign of being unclean! Given these facts it is sad that our collective over reaction to them causes many lost hours of work, wages and school and cost our country an estimated one billion dollars annually. Not to mention many, many hours of parental time spent treating and cleaning up after these yucky little creatures.
We will start first some bug facts:
- Lice are 2-3mm long (about the size of a sesame seed), gray-colored, move quickly and avoid light. They are therefore difficult to see.
- Nits are white eggs firmly attached to hair shafts near the skin and are easier to see because they are white and there are usually very many of them. Sometimes people mistake dandruff or lint for nits – you can tell the difference by trying to shake or flick them off – eggs stay stuck to the hair. Also, nits more than one cm from the scalp are unlikely to be viable – they are usually empty eggcases.
- The adult female louse lays about 10 eggs a day. These nits hatch into lice in about 1 week.
- Off the scalp, nits can’t survive over 2 weeks and cannot hatch at temperatures lower that human body temperatures.
- Adult lice survive 3-4 weeks on the scalp or less than 24 hours off the scalp.
- Lice crawl. They cannot hop or fly. Usually you get infested by direct contact with the head of an infected person and more rarely by using that person’s belongings (hats, combs, etc.). It is uncommon to get lice from sharing gear and a child should never be asked to not wear protective head gear (like batting helmets) for fear of sharing lice.
People who have hair lice usually have itchy scalps. However with a first time case of head lice the person may not develop itching for 4-6 weeks. Sometimes people get a red rough rash, worsened by scratching. They should not have oozing, pus, scabs or open sore areas – this may represent a different infection and they should be examined and treated by a doctor. Otherwise lice should be treated at home using over-the-counter medicines.
Time to treat:
- The first medical treatment should be with an over-the-counter crème rinse with permethrin 1% (sold under the brand name Nix) or pyrethrin (sold under the brand name Rid). The package directions must be followed very carefully to be sure they work and re-treatment should be done on day 9 for the highest effectiveness. To use the most common treatment – Nix (1% permethrin):
- First wash the hair with a non-conditioning shampoo, do not use a conditioner (it interferes with the medicine) and then towel dry.
- Apply a full bottle (two if very long or thick hair) to damp hair and work it through down to the scalp.
- Leave it on a full 10 minutes and then rinse off. It is best to rinse the hair in the sink not shower or bath to avoid contact with the skin.
- Don’t wash the hair with shampoo until 2 days after lice treatment
- Avoid hair conditioners before treatment and for 2 weeks afterwards
- If this is unsuccessful your doctor may suggest trying additional medicines that could include Malathion 0.5%, Benzyl alcohol 5%, Ivermectin or Sulfamethoxazole-Trimethoprim. However these prescription medicines have more associated risks and side effects than permethrin or pyrethrin so should only be tried after careful use of these first-line treatments.
- Itchiness will continue for several days after treatment and can be calmed with over-the-counter antihistamines taken by mouth or hydrocortisone cream rubbed on itchy areas of the scalp.
- Non medical treatments can be used by people who wish to avoid medicines or use together with the medicines. These include:
o applying oils or petroleum jelly (Vaseline) overnight under a showercap. A recent study showed that the use of petroleum jelly was more effective than other home agents including vinegar, isopropyl alcohol, olive oil, mayonnaise, melted butter.
o Another study showed success (96% cure rate) with the use of Cetaphil cleanser. This was applied to the hair, dried on with a hair dryer, left on overnight, and washed out the next morning. This was repeated once per week for 3 weeks.
o Heat drying has also been recommended by some. The LouseBuster is a custom-built machine that uses one 30-minute application of hot air to dry out the lice. Although studies have shown the machine works well it is expensive. A regular blow-dryer should not be used in an attempt to accomplish this result, because investigators have shown that wind and blow-dryers can cause live lice to become airborne and, thus, potentially spread to others.
- Shaving the head is of course, the most effective “treatment” but not one many people actually want to try! It should certainly not be used if shaving is upsetting to your child.
- After treatment to kill the lice and nits many people suggest combing out any remaining nits. Although this has been a longstanding recommendation, recent studies do not show that doing so does not improve results! Nit removal is done with a nit comb and should be targeted at removing the nits closest to the scalp those within 1 cm. Nit picking s slow, difficult and tedious. However, many a parent has commented that the time spent quietly talking one on one with their child became surprisingly enjoyable!
- Everyone in the household should be checked and if live lice or nits close to the scalp are found they should be treated. It seems smart to treat anyone who shares a bed with the person who has lice even if no lice are found on the family member
Time to clean:
- Here the most important point is that you do not need to go overboard! Live nits are unlikely to hatch at room temperatures and even if they did, they would need to find a source of blood for feeding within hours of hatching to survive. So follow a few tips for cleaning but, don’t exhaust yourself!
- Bedding and hair care items used by the infested person need to be cleaned. Only items that have been in contact with the head of the in the 24 to 48 hours before treatment should be cleaned, given the fact that louse survival off the scalp beyond 48 hours is extremely unlikely. Washing, soaking, or drying items at temperatures greater than 130°F will kill stray lice or nits. Furniture, carpeting and car seats can be vacuumed.
- Things that cannot be washed can be bagged in plastic for 2 weeks, a time when any nits that may have survived would have hatched and died.
After treatment your child should return to school. This year the American Academy of Pediatrics stated that school “no nits” policies should be abandoned; No child should be allowed to miss valuable school time because of head lice.
So, in summary let’s go back over a few important points:
- Lice are seriously icky! However, they do not carry disease and are harmless to your child. This makes it very important that the treatments for lice are also harmless and our reaction to the lice is as calm as possible.
- The bugs and nits do not live well off of our heads so, cleaning attempts should not be excessive. Your child did not get lice because they are dirty or your house is unclean!
- Treatment should in most cases start with the over-the-counter medicine called Nix. Any treatment should be done carefully according to directions and repeated in the specified time.
- Kids should not be kept out of school because of lice.