The most common type of bug found on the human scalp is head lice. Head lice are a parasitic insects that feed off human blood and can be transmitted via contact with other people. The parasites are found throughout the world, but are most common among school-age children.
Adult head lice can infect other people when they come into contact with infected clothing, bedding or furniture. The adults lay eggs, referred to as nits, which then hatch to continue the infestation. Some symptoms of a head lice infestation include itching of the head and scalp, sores on the head and difficulty sleeping.