Lice are tiny greyish insects, about the size of a sesame seed and barely visible to the naked eye. They live on human heads, close to the root of the hair, and sometimes on the eyebrows. Lice can neither fly nor jump, and live about 20 to 30 days.
Lice are irritating but not dangerous. They do not spread diseases and are not the result of poor personal hygiene. Lice are most common in children in a school or day care setting.
Lice lay eggs called nits. Nits stick to hair strands and are difficult to remove. Live nits are a greyish white colour and look a bit like transparent, oily and swollen dandruff. They are usually located within 6 mm of the scalp and take 7 to 12 days to hatch.
Dead nits are white in colour and dry. They are most often located more than 6 mm from the scalp.