Head lice are parasitic wingless insects that live in the hair and scalp of humans. Lice are not dangerous and they don't spread disease but they are contagious and can just be downright annoying. Though very small, lice can be seen by the naked eye. Their bites may cause a child's scalp to become itchy and inflamed. Persistent scratching may lead to skin irritation and even infection.
Head lice develop in three forms: nits, nymphs and louse. Louse and nits are easiest to detect at the neckline and behind the ears.
The eggs, called nits, are small like a dandruff flake. Nits are hard to see and are often mistaken for dandruff or droplets of hairspray. Nits are found firmly attached to the hair shaft. They are oval and usually yellow to white. Nits take about 1 week to hatch.
Nymphs are immature adult head lice. Nymphs mature into adults about 7 days after hatching. To live, nymphs must feed on blood.
An adult is called a louse and is about the size of a sesame seed. A louse has six legs and is tan to greyish-white. In persons with dark hair, adult lice will look darker. Adult lice can live up to 30 days on a person's head. To live, adult lice need to feed on blood. If a louse falls off a person, it dies within 2 days.
To see head lice, you need to look closely. Use disposable gloves and look at the person's head under a bright light. Full sun or the brightest lights in your home during daylight hours work well. A magnifying glass can also help. Part the hair all the way down to the scalp in very small sections, looking both for moving lice and nits.
Treat children and adults with lice promptly and thoroughly. Treatment is recommended if even one egg is found. Lotions and shampoos containing 1 percent permethrin (Nix) often work well. They can be bought at the store without a prescription. To use the medicine shampoo, first rinse and dry the hair. Then apply the medicine to the hair and scalp. After 10 minutes, rinse it off. Check for lice and nits again in one week and repeat the treatment if necessary. If these do not work, a doctor can give you a prescription for stronger medicine.