Lice are tiny wingless insects that live in the hairy parts of the human body. They are less than 1/8 inch long (2 to 3 millimeters), or about the size of a sesame seed. Lice that live in the hair on your scalp are called head lice.
Head lice bite the scalp to suck blood. They attach their eggs, called nits, to hairs. The nits hatch after several days, making more lice.
Lice are not dangerous and donâ€™t spread disease. However, their bites can cause itching and skin irritation.
How do I get head lice?
Lice can be passed from person to person through close body contact. Lice can spread from sharing personal items, such as combs, brushes, and hats. The lice can live up to 3 days away from the body, so you can get lice from clothing, bedding, sleeping bags, towels, or furniture. It is very common for schoolchildren to have head lice and pass them to other family members.
What are the symptoms?
The most common symptom is itching. The more lice you have, the more severe the itching. If there are only a few lice, you may have no symptoms.
Your skin may get red and irritated, especially if you are scratching your skin. You may have small, red, itchy bumps. Sometimes the areas that you have scratched can get infected.
Sometimes you may see the lice or nits. The nits look like tiny white dots attached to a hair, similar to dandruff. Unlike dandruff, the nits cannot be brushed or flicked off. They must be pulled off the hair with a fine-tooth comb or your fingers.
Head lice may also be in beards, eyebrows, and eyelashes.
How is it diagnosed?
Your healthcare provider will ask about your symptoms and medical history and examine you.
How is it treated?
Lice will not go away without proper treatment. Anti-lice products can be bought without a prescription and used to treat lice. Follow the directions on the package. Some products require a second treatment in 7 to 10 days, while others recommend repeating the treatment only if live lice are still found in the hair.
If a nonprescription product does not kill the lice, you may need a shampoo prescribed by your healthcare provider. Prescription shampoos contain medicines that may cause side effects. It is usually better to try one of the nonprescription products first.
If you are pregnant or breast-feeding, check with your healthcare provider before you use any type of anti-lice product.
If the lice are in your eyebrows or eyelashes, you will probably need to remove them carefully with your fingers. In some cases, your provider may prescribe medicine that is safe for use around the eyes.
After treatment with anti-lice medicine, the nits (eggs) will still be on your hair. You must remove all of the nits. Use a fine-tooth comb, tweezers, or your fingers to remove the nits. If you don’t remove all of the nits, it may be hard to tell if the treatment worked.
Check everyone living in your home and treat them if they have lice. Ask your healthcare provider to recommend the best treatment based on their ages and whether they are pregnant.
Clean combs and brushes by soaking them in hot water for at least 20 minutes.
You need to remove lice from your clothing, towels, and bedding. Machine wash all items that you used in the last 3 days before you started treatment. Use hot water to wash the items. After washing, use the hot setting on your clothes dryer for at least 20 minutes. Anything that cannot be washed this way needs to be dry cleaned. Clothing or other things, like stuffed animals or pillows, that may have lice but cannot be washed or dry cleaned should be sealed in a plastic bag for 2 weeks to kill the nits. Pets donâ€™t need to be treated because human lice do not affect animals.
How can I help prevent head lice?
Vacuuming the floor and the furniture used by anyone who had lice may help keep the lice from spreading. To help prevent head lice, donâ€™t share personal items such as combs, brushes, hats, scarves, and towels.
Lice can be very hard to prevent among small children who nap and play together. Because it is so hard to prevent the spread of lice among preschool and school-age children, lice should not be seen as a sign of poor health habits or failure by parents. The problem should just be dealt with in a calm and practical manner.
Developed by RelayHealth.
Adult Advisor 2015.1 published by RelayHealth. Last modified: 2014-06-02 Last reviewed: 2014-06-02
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.