During a visual exam for head lice , the hair on the head is parted with the fingers so that the scalp can be seen. You or the doctor uses a louse comb and looks for tiny live lice[about 3 mm (0.12 in.) to 4 mm (0.16 in.) long, or the size of a sesame seed]. If you are checking your child or someone else for lice, it may be helpful to use a handheld magnifying glass or have another person help you. The doctor may use a special light called a Woods lamp in a darkened room to see the lice better.
- Lice move quickly to avoid light, so they may be difficult to see.
- Eggs (nits) are small and white or light brown. They are usually found on the hair shaft close to the scalp. They do not slide up and down the hair shaft.
- If eggs are found farther from the scalp, the person may have been infested with lice for some time. If the eggs have already hatched, the empty egg cases may appear white.
Body lice and their eggs may be seen in the seams of clothing. They are usually not found on the body, although there may be small, red bumps on the skin where the lice have bitten. The lice look like large head lice and may be up to 4 mm (0.16 in.) long.
Why It Is Done
People with itching in areas of the body that are commonly infested with lice-the scalp, pubic area, or armpits-or people who have close contact with a person who has lice should do a self-exam or have someone help them look for lice and eggs.
Seeing lice or their eggs is enough to diagnose a lice infestation. Treatment is always needed to get rid of the lice.
What To Think About
People who have pubic lice are strongly encouraged to seek testing for other sexually transmitted infections.
Primary Medical ReviewerJohn Pope, MD - Pediatrics
Specialist Medical ReviewerSusan C. Kim, MD - Pediatrics
Current as ofSeptember 9, 2014