Q: We’ve barely started the school year, but there’s already been a letter sent home about students with lice! What do I do if my child gets lice, and how can I prevent it in the first place?
A: Ah, what better way to greet back-to-school than that old friend of the child, head lice!
This bug is named Pediculus humanus capitis and is very common in younger school-aged children. In fact, some estimates from the Centers for Disease Control suggest that there are likely 6-10 million infestations every year, and there are only about 40 million school-aged kids in the US! Is your head itching yet? It seems that white children are the most likely to get head lice, and girls are more likely than boys. It is not clear why this is, but may be related to hair styles and hair structure.
Lice are passed from human to human, mostly from head-to-head contact. Lice don’t fly through the air, jump off of dogs to humans, and actually are not usually passed from inanimate objects like a comb or hat. They are not as “catchy” as people give them credit for being. In fact, the newest American Academy of Pediatrics guidelines suggest that school districts should not exclude children from school due to lice and that “no nit” policies should be eradicated.
These 2-3 millimeter bugs live on the scalp and plant eggs on the hair shaft at the base. As the hair shaft grows, the egg grows out from the scalp, and even after the egg is empty the case often stays on the hair shaft. Because of this you can time when there was an active infection by seeing how far off the scalp the nits are on the shaft and knowing how fast hair grows.
Treatment of lice can be difficult, time-consuming, and frustrating. The methods are basically physical treatment methods and pediculocidal methods that stop the infection by poisoning the bugs. A basic method is nit and lice combing. This not only helps with diagnosis by helping you see lice or nits as you comb it out, but it also helps decrease the number of eggs on the hair. Other treatment methods essentially smother or physically kill the live lice. These treatments usually are applied and left on the hair overnight, then washed out in the morning. Lice can hold their breath for a long time, which is why they don’t die during showers or baths, so the suffocating material has to be left in the hair overnight. Mayonnaise, olive oil, and Eucerin cream are examples of things that are used for this. Gasoline should never be applied to children’s heads to kill lice, though this is something that was done by some people in the past.
Finally, there are a variety of medications that can be used to kill the lice. The most common one is 1% permethrin cream that is available over the counter. Other options include topical higher concentrations of permethrin, malathion, ivermectin and then oral antibiotics and oral ivermectin. Remember that hair lice are a nuisance and irritant, but they are not dangerous — so be sure all treatments you try are also safe and not dangerous.
Dr. Mike Steiner is a pediatrician in the division of General Pediatrics and Adolescent Medicine at UNC and North Carolina Children’s Hospital.