Fear and anger -- these are some common emotions that occur when a loved one is diagnosed with head lice. But these emotions are often greater than the health impact that head lice causes. Yes, they are annoying; but they do not transmit disease and, with proper treatment, can be eliminated.
Also called Pediculus humanus capitis, head lice are small, wingless insects found on the heads of people. A head louse (head lice is plural) has three pairs of legs located directly behind the head. The legs end in sharp claws that are designed for feeding and allow the louse to hold on tightly to hair or clothing. The head louse is the largest of the three types of lice (the pubic louse, or crab louse, is the smallest).
When a person is infested with lice (whether it is head lice,
body lice, or
pubic lice), the condition is known as pediculosis.
Having head lice is quite common. However, there are no reliable data on how many people become infested in the United States each year. While anyone can get head lice, it is more common in children. It is also more common in girls.
One common myth is that personal hygiene or cleanliness in the home or school affects the chances that a person will get head lice. This is not true.
How Are They Transmitted?
Head lice are highly contagious. Direct head-to-head contact with an already infested person is the most common way that the spreading of head lice occurs. They may also be spread through contact with infected clothing, combs, or bedding.
Head lice are quite active and can travel quickly, which explains why they are transmitted so easily. But head lice are not long-distance travelers, and they do not do well away from the host. Although adept at moving from hair to hair, they cannot jump or crawl very far (from the floor to someone's head, for example).
The three forms of head lice are:
- The egg (also called a nit)
- The nymph
- The adult.
The Nit
Nits are head lice eggs. They are very small (about the size of a knot in thread), hard to see, and are often confused for dandruff or hairspray droplets. They are oval and usually yellow to white in color. Nits take about one week to hatch. Once hatched, they are white or clear in color.
Nymph
The nit hatches into a baby head louse, called a nymph. It looks like an adult head louse, but is smaller. To live, the nymph must feed on blood.
The Adult
The adult louse is about the size of a sesame seed, has six legs, and is tan to grayish-white in color. Adult lice can live up to 30 days on a person's head. To live, adult lice need to feed on blood. If the louse falls off a person, it dies within two days.
Head lice feed about five times a day. To feed, they pierce the skin with their sharp claws, injecting irritating saliva and then sucking the blood that flows out.
Signs and Symptoms of Head Lice
The most common symptom of head lice is itching. This is because the head lice saliva causes an allergic reaction. Keep in mind, however, that not everyone with head lice will have symptoms.
Head lice can be anywhere on the scalp, but are most commonly seen behind the ears and on the back of the head near the neckline. When looking at the scalp, very few head lice are usually seen. This is because they move rather quickly. However, there are usually many nits (lice eggs) at the base of the scalp.
Head lice is diagnosed by looking closely through the hair and scalp for nits, nymphs, or adults. Finding nits within a ¼ inch of the scalp confirms that a person is infested and should be treated. If you only find nits more than a ¼ inch from the scalp (and don't see a nymph or adult louse), the infestation is probably an old one and does not need to be treated.
The first thing to know about getting rid of head lice is that there are many options. The second thing to know is that there are no guarantees that these treatments will be 100 percent effective -- data from clinical trials are not available for all treatment options.
To get rid of head lice, you must do two things: kill the live lice on the head, and remove all the nits (eggs) from the hair. This involves three necessary treatment steps:
Treating head lice is a long process that can take up to 21 days. It is not necessary for a child to miss school once treatment begins.
