In the beginning, children who have head lice may not notice the lice at all aside from experiencing vague scalp irritation. The lice are easiest to spot at the neckline and behind the ears.
The adult louse feeds on blood by biting into the scalp every four hours or so. A lice infestation can be asymptomatic for two months before itchiness of the scalp occurs.
Itchy papules develop and these often become infected from scratching, resulting in infection of the scalp. The lymph nodes at the back of the head and in the neck are frequently enlarged. The eyelids can also be involved.
In adolescents, pubic and axillary hair may be infested.
Other symptoms of head lice include:
- A tickling sensation like something is crawling in your hair
- Intense itching that causes red bumps due to an allergic reaction to the saliva that lice inject while feeding
- Lice nits that resemble tiny buds which can be mistaken for dandruff
The doctor will diagnose head lice by using a special light, called Wood's light under which the nits appear pale blue.
Using a fine-toothed comb is also another effective way of identifying head lice. Stroke it from the crown of your head downward over the scalp at least twice.
However, finding nits this way doesn't mean that there is a live active infestation. The best way to identify an infestation is if you find a live louse.