The diagnosis of head lice infestation is best made by finding a live nymph or adult louse on the scalp or hair of a person. Because adult and nymph lice are very small, move quickly, and avoid light, they may be difficult to find. Use of a fine-toothed louse comb may facilitate identification of live lice.
To confirm a case of head lice, you need to find live lice. Children can have a few nits without actually having a case of head lice. Usually children have no more than 10 to 20 live lice.
Infestation timeline
So if you look on the scalp and see no visible adult lice and several small nits, it's likely that you've caught lice in the earlier stages and had them for less than 2 weeks. Nits and nymphs: 1.5 to 2 weeks. If you see nits and small, moving lice, you've likely had lice for 1.5 to 2 weeks.
Itching on the areas where head lice are present is the most common symptom. However, it may take up to 4 to 6 weeks after lice get on the scalp before the scalp becomes sensitive to the lice saliva and begins to itch. Most of the itching happens behind the ears or at the back of the neck.
Not everyone feels lice moving around on their scalp, but some people do. Dr. Garcia says that most of her patients say they “don't feel anything,” but others may get a creepy, tickling sensation as lice move around their head.
The oval-shaped eggs often look yellow or white but may be the same color as your hair. They are found on the first 1-2 inches of hair shaft closest to the scalp (not the end) and are hard to remove. You may confuse them with dandruff or flakes from hairspray build-up. Head lice nits usually hatch in 8 to 9 days.
Doctors call head lice eggs nits. They are small, are 0.8 to 0.3 millimeters (mm) in size, and appear as oval- or teardrop-shaped eggs. Their color may range from white, yellow, tan, or brown, so they may be hard to see. Eggs look darker when alive and pop between the fingernails.
You can get body lice similarly from clothing or from close physical contact with a person who has them. Head lice are more common in younger children because they require even more physical contact for transmission. Usually, you would have to be in head-to-head contact with a person who has lice.
They are small, oval-shaped, usually a yellowish-white color, and are firmly attached to the sides of hair shafts. The terms can be confusing because some people only use "nits" to refer to empty egg casings while "lice eggs" is used for eggs that can hatch (viable eggs).
Typically, 10–15 head lice are found. The number of lice often depends on personal hygiene, for example, how often the person bathes, shampoos, or changes and washes his/her clothing.
They bite anywhere they are feeding on the head, but they are particularly fond of the back of the head and the area behind the ears because this is a warmer area of the scalp. The bites often appear as small reddish or pink bumps, sometimes with crusted blood. When scratched excessively, the bites can become infected.
Even if no one in our family shows signs of pediculosis, I itch. Known by psychologists as a “hysterical condition,” psychosomatic itching is nonetheless a “genuine physical affliction caused by emotional anxiety,” says San Francisco-based psychologist Juli Fraga. That means the problem is real.
Location: Lice lay eggs called nits while dandruff causes flaky skin. The two look similar, but close inspection reveals key differences. Nits stick to the hair while dandruff flakes, easily falling off of hair. While dandruff is visible on the scalp, lice lay eggs on hair, not the scalp.
Head lice survive less than one or two days if they fall off the scalp and cannot feed. Head lice eggs (nits) cannot hatch and usually die within a week if they do not remain under ideal conditions of heat and humidity similar to those found close to the human scalp.
You can find head lice on the scalp, neck, and ears.
Body lice live in your clothing and bedding and travel to your skin several times a day to feed on blood. The most common sites for bites are around the neck, shoulders, armpits, waist and groin — places where clothing seams are most likely to touch skin.
The peak season for lice infestation is August through October and again in January. Head lice are tiny parasitic insects that feed on human blood. Lice come in three forms: nits (eggs), nymphs (baby lice), and adults. Nits are white or yellowish-brown and about the size of a poppy seed.
Reliable data on how many people get head lice each year in the United States are not available; however, an estimated 6 million to 12 million infestations occur each year in the United States among children 3 to 11 years of age.
Lice are tiny, but you can still see them — though it's not always easy. An adult louse is grayish white or tan and about the size of a small sesame seed. Lice move fast, so you're actually more likely to see their eggs than the lice themselves. Louse eggs are called nits.
They are very small and will be a dark golden-brown colour if they are about to hatch or are white if the louse has already hatched and left the egg. If they are full then they will be plump and shiny. What does a dead lice egg look like? A dead lice egg will be white or grey.
What are the symptoms of head lice infestation? Symptoms include a tickling feeling of something moving in the hair, itching caused by allergic reaction to the bites, irritability, difficulty sleeping (head lice are most active at night), and sores on the head caused by scratching.
Females start laying eggs 1-2 days after maturity. Body lice live from 30-40 days and survive best at the body temperature of humans. A four to five degree rise in temperature is fatal for lice. They prefer cold environments where clothing layers provide a humid to dry gradient.
Repeat treatment every day or every other day for 2 weeks. Some lice eggs (nits) survive head lice treatments. The only way to be sure that lice won't come back is to pick out all nits. Nits left on the hair can hatch and cause a new case of head lice.