Lice are wingless, tiny, parasitic insects that feed themselves on human blood. They can be very easily spread — especially by school-going children — by sharing belongings and close personal contact.
Head lice are found mostly behind the ear and on the back of the neck. Although lice can’t fly or jump, they can spread easily from one person to another through head-to-head contact or by sharing clothing or personal items (such as a hairbrush, hat, or a towel). Contrary to a famous myth, getting head lice has nothing to do with personal hygiene.
Adult female lice lay six to nine eggs per day on your scalp, and they spread from there. Lice have three forms. Nits, or eggs are laid onto the shaft of the hair. The eggs that are less than 5-6 millimeters from the scalp hatch mostly. These eggs are usually attached to the hair by sticky secretions from the female louse.
The eggs hatch within a week, producing a nymph. These nymphs then go through three successive growth spurts. During these stages, they molt until they become adults.
Adult lice are nearly the size of a sesame seed, and sometimes it is difficult to see them because they can be of any color from brown to white to tan.
Lice usually feed on human blood four to five times a day. They use their mouthparts to bite the skin and then secrete a substance to block clotting.
It is important to note that anyone can get lice infestations; however, some people are at a higher risk of getting lice.
- Nits, or lice eggs –They’re tiny– about half the size of a pinhead. It is hard to see them. The oval-shaped nits often look white or yellow, but may have the same color as your hair. Nits attached at the first 1-2 inches of hair shaft near the scalp are very hard to remove, but those at the end of the hair come off quite easily. You may confuse these tiny eggs with flakes from hairspray build-up or dandruff. Head lice eggs usually hatch in 7 to 9 days. When they hatch, they leave behind transparent shells that remain attached to the hair shaft and appear more grayish.
- A nymph– It is a baby louse. It’s the one that hatches from the nit. It feeds on your scalp blood and continues to grow for 9 to 12 days. Nymphs (as well as adult lice) avoid light and move quickly. Mites begin to appear in your scalp and hair, on your skin, and on any other thing that comes in contact with your head. Itching might not start at that time.
- Adult lice – These are about the size of a sesame seed, 2-3 millimeters long. They’re grayish white or tan. The color can be darker or lighter, depending on your hair color. Adult lice contain six legs with claws at their ends that allow them to hold your hair firmly. Typically, adult head lice can live 30 days within your head. If they fall off from your head, they die within 1 to 2 days.
1Types Of Lice
Lice are of three types:
The head louse is a grayish-white parasite about 2-3 mm in length. A female louse lives for about one month. During this period, she produces about seven to 10 eggs (“nits”) each day and attaches them firmly to the shaft of hair close to the scalp. These grayish-white nits, resembling dandruff, are attached to a water-insoluble, cement-like substance that makes it difficult to remove them. After seven to ten days, these oval-shaped nits (eggs) hatch as nymphs and become adult lice in 10 days.
The most common form of lice infestation is head lice. A report states that several million people in the world are infested each year. Children aged 3-10 years in daycare centers, preschool, and elementary school are more likely to get lice. Lice can affect all socioeconomic classes. Girls are more prone to lice infestation, but personal hygiene or hair length is not predictive factors. African Americans usually don’t get a lice infestation due to their unique hair characteristics.
Head-lice spread mostly via direct head-to-head contact. Sharing caps, headphones, combs/brushes, and pillows are notorious ways to spread head lice. The louse dies due to severe dehydration within two days if they do not feed on their human host. Therefore, contact with couches and carpeting is less commonly considered as a route of transmission. Mostly lice infestations do not cause any symptoms (i.e., they are asymptomatic). However, sometimes symptoms are present, like itching of the neck, scalp, and behind the ears is the most common symptom. Severe scratching may give rise to secondary skin infections (such as impetigo) and enlargement of the lymph nodes of the various regions of the scalp and neck.
The diagnosis is made by demonstrating nits or adult lice. Nits are mostly examined using a black light (“Wood’s light”) that causes them to appear as pale blue objects stuck to the hair shafts and the scalp. Running a fine-tooth comb through the hair will also demonstrate nits and adult lice.