What are the Most Common Signs of Head Lice?

The most common signs of head lice include the appearance of lice eggs, or nits, on the hairs on a person's head. Other signs of head lice include an itchy scalp and live lice on the head. The lice may also be on a person's neck and ears.

Unhatched nits, one of the most obvious signs of head lice, are small yellow or brown specks attached to a hair shaft. Adult lice tend to lay the nits near a person's scalp, as heat from the head keeps the eggs warm. After hatching, the nits are whitish and may resemble dandruff. Unlike dandruff, nits cling to the hair and cannot be easily brushed away.

The appearance of full-grown lice and baby lice, or nymphs, are other common signs of head lice. Lice and nymphs are very small but can still be seen by the human eye without magnification. Adult lice are usually about the size of a sesame seed and can grow up to 0.125 inches (0.318 cm). Nymphs are much smaller but become full grown within a week of hatching. Lice have six legs and are a gray color, though they can look darker on dark-haired people.

An itchy scalp and redness are other signs of head lice. Lice feed on blood, which they get by biting into a person's scalp. Usually, the saliva from the lice causes an allergic reaction, which makes the skin on the scalp feel itchy.

Children are more likely to get a head lice infestation than adults and are more likely to be unable to control the scratching. Excessive scratching can irritate the skin on the scalp, causing redness and bumps to appear. In some cases, the skin can become infected with bacteria if a person scratches too much.

Head lice can be treated by washing the hair and scalp with an over-the-counter shampoo. The shampoo contains a medication that kills the lice and their nits. In some cases, lice have become resistant to the medicine in over-the-counter products. If that is the case, a person may need to use a prescription shampoo or cream.

Medicated shampoo isn't recommended for very young children, and some adults and older children may wish to avoid it as well. Another way to remove lice and nits is to carefully comb through the hair. A metal comb should be used, as it will effectively pull the nits off of the hair shaft.