October 2003

I hope the school year has begun on a happy note for you and your children. Remember, you can always grab old copies of the “Pediatric Arts Gazette” including editions that are not on display. We are purchasing a new computer system for our office. Maybe this will make Gazettes available by e-mail. Stay tuned!

Dr. Barenfeld

Head Lice----------------------------------------------

Head lice have plagued humankind for at least 5,000 years. Lice were mummified with ancient Egyptian nobility and have been recovered from 2,000 year old tombs excavated from the Judean Desert. Since those early days, lice have been the cause of much embarrassment and misunderstanding, many unnecessary days lost from school and work, and millions of dollars spent on remedies.

Head lice infest 6 to 12 million persons in the U.S. every year, most of them school age children. An estimated $100 million is spent annually on treatment of louse infestations.

The adult louse requires the human scalp for food, warmth and shelter. It will not survive in any other environment. It is a six-legged, wingless parasite that feeds on human blood. They are cigar-shaped, about the size of a sesame seed. All socioeconomic groups are affected. Short or long, clean or dirty, any style coiffure will do for the louse! They are not affected by frequent brushing or shampooing. Girls do have a higher frequency of infestation but this has been attributed to girls’ tendency to play more closely with one another than boys do. Infestation is also less likely in African Americans because lice have a harder time adhering to their circular hair shafts. Head lice are not dangerous and do not carry disease. They cannot hop or fly. Transmission in most cases occurs by direct contact with the head of another infested individual. Much less often they can be spread by sharing of combs, brushes and hats of an infested individual. However, without a human host, lice will dehydrate and die within six to twenty hours.

Let’s take a quick look at the life cycle of the louse. I know you are all waiting with bated breath to hear this! Adult lice lay their eggs and attach them to the hair shaft close to the scalp with a quick-setting glue. The eggs and their shell casings are called nits. They are very difficult to see and remove. Empty nit casings are easier to see and appear white against darker hair. The eggs hatch in 10 to 14 days and are called nymphs. The nymphs feed, undergo three molts and become mature adults in about twelve days. Adults mate, lay eggs one to two days later and produce more than 100 eggs during their 30 day lifetime. Are we all feeling itchy by now? I took a Benadryl before I started writing!

Speaking of itching, this is the main symptom of lice infestation. Infections of the scalp sometimes occur due to scratching. However, keep in mind that by the time serious itching occurs, the infestation has probably been in place for at least one month. Many people have no symptoms and only know they have an infestation when somebody else sees it.

The gold standard for diagnosing head lice is finding a live louse on the head. This is difficult, as the insects tend to hide among the hair shafts in response to light or a disturbance in the hair. Ideally, an examination for lice should last for 3 to 5 minutes and be conducted in a well lit room. Part the hair and comb through in small sections using a fine-tooth comb. After each comb-through wipe the comb on a wet paper towel. Examine the scalp, comb, and paper towel carefully. A magnifying glass may be needed to tell the difference between dandruff or other hair debris and nits. Also, people who have an infestation usually have no more than a dozen lice in their hair at any one time. Finding nits is not diagnostic of infestation. Empty eggs are not proof of an active infestation and unhatched eggs may not contain living nymphs.

Treatment begins by identifying which members of the family are infested. Everyone with signs of infestation should be treated at the same time to prevent reinfestation from one family member to another. Only those with signs of definite infestation need to be treated. In general, there are three steps to treating head lice – kill the lice, comb out the nits, and prevent lice from spreading.

Pediculicides are shampoos used to kill head lice. The best ones are available in pharmacies without a doctor’s prescription. Pyrethrins are manufactured from natural extracts from the chrysanthemum. The most common product of this type is RID. The label warns against possible allergic reaction in people who are sensitive to ragweed, however, this is rare. The product is otherwise extremely safe. It should be applied to dry hair paying careful attention to proper instruction. Since some eggs may survive its use, these products should be applied a second time 7 to 10 days later. Permethrin (Nix) is a synthetic compound that will not cause allergic reactions in ragweed sensitive persons. The product is a cream rinse applied to hair that has been washed and towel dried. Nix will leave a residue on the hair that is designed to kill nymphs emerging from the eggs that were not killed during the initial shampooing process. Reapplication 7 to 10 days later is recommended if live lice are still seen. A stronger Permethrin product by prescription only (Elimite) can be used if resistance to the milder product is suspected.

Lindane (Kwell) is a prescription product that should no longer be used due to serious side effects, including severe seizures in children. Malathion (ovide) is a prescription product. Although highly effective, its high alcohol content makes it highly flammable and if ingested can be fatal. For these reasons it should be rarely used. Finally, reports indicate that applying a heavy layer of petroleum jelly, mayonnaise or olive oil and covering the scalp with a shower cap overnight kills lice, probably through suffocation. This is messy and difficult to rinse out of the hair. Resistance to pediculicides seems to be increasing, however the prevalence of resistance is not currently known.

Comb out the nits. This step is not really necessary but you and your child will feel better knowing that the nits are removed. It may also prevent your child from being misdiagnosed with an active infestation. Also many schools have a “no nit” policy such that your children will not be allowed back to school even with empty or dead nits in their hair. The American Academy of Pediatrics discourages such policies and further states that “no child should be allowed to miss valuable school time because of head lice.” Non-prescription products to loosen the nits and combs to remove them are readily available.

Prevent lice from spreading. You do not need to fumigate your house or throw out your child’s belongings. All clothing, towels, hats and bed linens should be machine-washed in hot water and dried on high heat if used in the two days prior to treatment. Dry-clean items that are not washable. Brushes and combs may be soaked in dish detergent and hot water for an hour then rinsed. Vacuum the floors, furniture and don’t forget the car seat. Stuffed animals should be washed as well. Wow, look at the time! Time for another dose of Benadyrl. Bye.