Lots of words can cause parents of school-aged children to feel uneasy or a sense of panic, but which one can make their skin crawl? Lice. No parent wants to get the letter that begins with "Dear Parent/Guardian: There has been a case of reported head lice at _______."
If you have ever been the recipient of such a letter (I have, a few times!) or if you want to be prepared in case you ever are, then take a few moments to review the answers to the following common questions about these pesky creatures and how to deal with them efficiently and effectively.
What are lice?
Lice (Pediculus humanus capitis; singular, "louse") are wingless parasitic insects that spend their entire lives on the human scalp dining entirely on blood. Head lice can survive on a human host for about 30 days.
A female louse can lay 3 to 5 eggs daily. It takes 7 to 10 days for the eggs to hatch and another 7 to 10 days for a louse to mature and begin to lay its own eggs.
Infestation with head lice is most common among preschool and elementary school-age children and their household members (the first time I was introduced to lice was when my middle daughter was in grade 1. Her head was covered in bugs after a summer at camp. Yuck!) Although these insects do not appear to transmit any diseases, people can develop secondary bacterial skin infections as a result of scratching.
The Centers for Disease Control and Prevention notes that reliable data on head lice infestation is the United States is not available. However, it's estimated that up to 12 million infestations occur annually among kids ages 3 to 11 years.
What are the causes of infestation?
A common myth about these pests is that they are related to the cleanliness of individuals or their environment. In fact, head lice are typically spread by direct contact with the hair of an infected person. Such contact usually occurs at school (girls love to hug each other), home (snuggling with our kids), or while engaging in play or sports activities, slumber parties, and in playgrounds or camps.
Lice don't fly or leap from one child's head to another. However, if an infected child is huddled up next to another child while they are playing a game or coloring and their heads (and hair) touch, it is possible for the insects to move to the uninfected child.
In fact, these pests cling to hair with tenacity. In a series of experiments, lice-infested hair was placed in regular water, seawater, salt solutions and cholorinated water. The lice hung on for dear life. They cannot swim.
Infrequently, transmission of these insects occurs when infected kids share clothing or hair accessories. It also is not common for transmission to occur when using infested towels, lying on a bed, pillow, or couch of someone with lice, or sharing stuffed animals that have come into contact with someone with lice.
Here's what some of the scientists have found. In a study that involved more than 1,000 hats worn by children who (combined) had more than 5,500 lice on their heads, none of the hats had the pests. Experts reported that the risk of transmitting lice from toys, hairbrushes, and other hair accessories is minuscule.
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What are the symptoms of lice infestation?
The most common symptom of this infestation is itching, which is caused by a person's allergic reaction to louse saliva. Approximately 14 percent to 36 percent of people with head lice experiencing itching. Along with itching, many people with a lice infestation experience a head lice rash, which appears on the back of the neck. In some cases, the cervical lymph nodes become enlarged as well.
It typically takes 4 to 6 weeks for a reaction to the saliva to occur. If a child is infected again in the future, itching usually begins after just two days. Anyone who experiences an extremely heavy infestation could develop anemia.
How do you check for lice?
The most efficient and effective way to check for lice is to use a fine-toothed metal lice comb and some conditioner. First work some conditioner into your child's hair and then slowly pull the comb through the hair. Look for pepper-sized nits (head lice eggs), which can be brown or white and tightly attached to single hairs.
Be sure to make contact with the scalp, because that's where the live nits stay. They must be close to the scalp to survive. Hatched nits get no bigger than a sesame seed and they also stay close to the scalp in order to feed.
Visual inspection has and is still typically used to locate an infestation. However, research has suggested that visual inspection "underestimated the true prevalence of active infestation" and that the sensitivity of wet combing was "significantly higher than of visual inspection."
Where can these pests live?
Lice live and thrive on the scalp because they need blood in order to survive. Once away from the host, however, they rarely last for more than 24 hours.
Although it's commonly been believed that lice can live and thrive in your pillows, sheets, sofas, stuffed animals, hats, and hair accessories, researchers have not found this to be the case. In a 2016 review, the authors reported that while parents can clean hair brushes in hot soapy water, "the risk of transmission is negligible."
They also explained that "treatment of furniture upholstery and carpets is not necessary since the lice…only survive for a short time away from their host." You may be familiar with the recommendation to keep underwear, soft toys, and bed linens in a closed plastic bag for three days to kill the lice. The investigators noted that "this recommendation has no basis in science."
How do you treat an infestation?
No over-the-counter or prescription lice treatment is 100 percent effective. The safest and best way to treat lice is to do it manually by combing the hair every 1 to 2 days over a 10-day period and picking out the nits. It may sound a little yucky, but it works! Click here to learn all the details and some great tips.
You also can consider using one of the several natural, over-the-counter products. They include Lice B Gone, Lice R Gone, HairClean 1-2-3, and ClearLice. All are nontoxic. Other over-the-counter products typically contain pyrethrins (a natural extract of chrysanthemums) or permethrin, a synthetic similar to natural pyrethrins. High exposure to pyrethrins or permethrin can cause respiratory and nervous system problems.
Several prescription products are also available. They include malathion (which is flammable), ivermectin (headaches, nausea, skin irritation, confusion), spinosad (itching, red eyes, burning scalp), and lindane (itchy dry red skin, dizziness, drowsiness). Read more about lice treatments here.
Lice may make you queasy, but they are not contagious and can be eliminated with a little patience and daily care. If you get that letter from school—and we hope you never do—you will be prepared to fight off the little critters!