Also known by their scientific name, Pediculosis capitis, head lice are tiny parasites that feed off the blood of the human scalp. About the size of a sesame seed, they must have a human host to sustain life, and pass from host to host through head to head contact or the sharing of personal belongings. Their eggs, known as nits, are small and whitish or yellowish in color and attach to the hair shaft near the scalp.

While head lice are often associated with intense itching, it may take several weeks before this symptom manifests. Early symptoms may include a sensation of movement on the scalp or red marks behind the ears and around the nape of the neck. When the lice bite into the scalp, the saliva causes an allergic reaction, which can then result in itching. Young children may also suffer irritability and sleeplessness.

Sorry, this entry is only available in European Spanish.

Head lice are not known to cause or transmit disease, but an infestation left untreated can result in open sores, which may lead to infection.

Unfortunately, no. Lice will continue to lay new nits and the infestation will only multiply. Even one bug left behind can launch a new infestation. This is why prompt, effective treatment is essential.