Lice and nits can be identified when an affected individual experiences itchiness on certain parts of the body where lice are commonly found, such as on the scalp; nits (the insects' eggs) may be visible on hair shafts or strands. Determining whether someone has head lice is not easy, which is why it may be a good idea to contact a health care provider to verify the situation before treatment can begin, according to Mayo Clinic.
Head lice usually attach on the human scalp and feed on blood from their host. It is difficult to see these insects since they avoid light and hide under human hair. However, closely examining the hair on the head of a person suspected to have the insects may reveal the insects, especially if they have multiplied in number.
Another way to know whether a person's hair may be infested is by observing whether they display symptoms of itchiness around the ears, head and neck. It is these parts of the body that the insects bite when sucking blood from the host, which causes the affected individual to experience an itchy sensation.
Close observation of the hair may also reveal nits or eggs attached to the shafts or strands of hair. School-going children and their caregivers are at the greatest risk of infestation, according to Medicine Net.