Social class and level of personal cleanliness are not predictors of infestation. Keeping hair short, brushing it or shampooing it have no effect on the likelihood of infestation. Symptoms are usually mild and may be absent. Itching is the main complaint, occasionally accompanied by excoriation and crusting. Rarely, a secondary bacterial infection and regional adenopathy may develop.
Diagnosis is made by careful inspection of the scalp.
The adult louse is 2 to 4 mm and grey and may be found near the hairline at the nape of the neck and behind the ears. They are firmly attached and cannot be easily removed, distinguishing them from normal hair scale. Once infestation with Pediculus capitis is diagnosed, treatment is required. There are a number of agents available. Although there is some preliminary evidence that it may work, there are no published studies of its efficacy.