Lice, also known as pediculus capitis are parasites  that live externally on warm-blooded hosts such as birds, and humans. These insects can feed on the skin anywhere in the body, including the head, neck, and arms. They prefer warmer areas, so are often found on the head, especially the back of the head and the area behind the ears. If you often experience a crawling sensation on your scalp, your hair could be infested with this insect. The bites will be evident on an infested scalp as small reddish or pink bumps. Avoid scratching the bites as it may cause bleeding and can lead to infections.
Children are more susceptible to get infested  with head lice, and it is often transferred to the heads of other children living in the same area. This insect can live up to thirty days on the scalp and requires special hair care treatment to get rid of. Contrary to popular belief, having head lice isn’t caused by poor personal hygiene or an unclean living area. Also, this parasite does not carry bacterial or viral infectious diseases, but the bites can become infected if left untreated.
This parasite is easily spread by coming in contact with an infested hair. In rare cases, sharing hair products like combs and brushes can also transfer lice from head to head. Getting rid of head lice  isn’t as easy as getting rid of other insects because their feet have special features that make it easy to hold onto human hair for long periods.
In some cases, the host may have an allergic reaction to lice bites, causing intense itching for up to seven or ten days even after getting rid of the parasite. Steroid creams are most effective to alleviate this symptom. Calamine lotion is a topical treatment for lice-related itching and severe itching, antihistamine pills have proved effective.