Head lice on blond hair appear paler than those on black or brown hair. All head louse life stages are found in the hair near the scalp. They are prevalent on the back of the neck and behind the ears. Head lice are rarely found on eyelashes or other hairy parts of the body. In severe infestations the hair may become matted as a result of exudates from louse bites.
Head lice can survive three to four days once dislodged from the host.
Head lice are transferred from one infested person to another through physical contact and the communal use of combs, hair brushes, head apparel, towels, bedding, and personal clothing. This insect is generally associated with unclean environments where inadequate bathing occurs or clothes are shared. The body louse lives on clothing that comes in close contact with the human body, such as the waistline and crotch of trousers, shirt armpits and collars, and underwear. This insect visits the human body only to obtain a blood meal. The life cycle of the body louse is similar to that of the head louse in many aspects.