Overview
Also known as pediculosis or ‘nits’, head lice is a common infection in children caused by the parasite Pediculus humanus capitis.
The lifecycle of a head louse has 3 main stages:
- Louse eggs (ova) – oval-shaped, translucent, and may appear similar to dandruff:
- They hatch within 7 days, leaving behind empty shells that turn white but are attached to hair – this is what ‘nits’ often describes
- Nymphs – baby lice that are pinhead-like in appearance and white and mature after 7-10 days
- Adult head lice – around 3 mm long (similar size to a sesame seed) and are tan-grey
Head lice are completely dependent on the scalp for warmth, and nutrition from blood.
Transmission
Head lice cannot jump, fly, or swim, or be transmitted via pets. They require head-to-head contact.
Epidemiology
- Most common in children aged 4-7 years old, but can happen at any age
- More common in girls than boys
Diagnosis
Head lice can lead to itching. Its diagnosis is made by combing wet or dry hair with a fine-toothed comb.
Management
Overview
If live lice are found, treatment options include malathion, wet combing, or dimeticone.
Household contacts do not require treatment unless they have head lice.
School exclusion is not necessary.
Prognosis
- If untreated, head lice infestation may persist and lead to complications such as a pruritic rash on the neck and behind the ears (due to a hypersensitivity reaction to louse faeces), excoriation, and secondary skin infection (e.g. impetigo) due to scratching.
