Head Lice Lawrence Pike

Introduction Head lice are one of the most common human ectoparasites They do not carry serious diseases In many cases they do not cause symptoms

Symptoms Many patients are asymptomatic, the lice and nits only being detected by careful examination of the scalp. Pruritus is a common symptom. Excoriations may lead to impetigo and furunculosis. Head lice infestation usually starts above the ears and around the hair line. They are rarely found in eyelashes or eyebrows. The live lice and nits are usually visible to the naked eye, but a magnifying glass may help. The duration of infestation may be estimated by the distance from the scalp surface to the nit on the hair shaft (the hair grows about 5mm per week).

Signs Head lice infestation usually starts above the ears and around the hair line. They are rarely found in eyelashes or eyebrows. The live lice and nits are usually visible to the naked eye, but a magnifying glass may help. The duration of infestation may be estimated by the distance from the scalp surface to the nit on the hair shaft (the hair grows about 5mm per week)

Causes Social status means nothing to lice. They are common amongst children and infection has nothing to do with dirty living. Head lice cannot fly, jump or swim but are spread by clambering from head to head. Anyone with hair can catch them.

Detection Head lice are well camouflaged and hide when disturbed by combing. If few in number they can be difficult to detect. To check for lice, comb the hair regularly while wet with a fine-tooth comb. Use a conditioner to make combing easier.

Self Care Do not use any form of treatment unless you find a living, moving louse. There are two treatment options:

Self Care Lotions using insecticides Check all close family/ friends by the “wet combing” method and treat anyone who is found to have lice at the same time, to prevent re-infection. Ensure you have enough lotion to treat all those affected and follow the instructions on the packet carefully.

Self Care The “Bug Busting” treatment method This aims at systematic removal of live lice by combing through the hair and physically removing any lice found. Success depends largely upon adopting a painstaking approach – as described in the “Bug Busting” kit available from some pharmacies, and by mail order from Community Hygiene Concern (Helpline: 0208341 7167)

Self Care, which is best? A recent study suggested that insecticide lotion was more effective than “bug busting”.

Self Care Alcoholic preparations work best If paying for prescriptions then treatment may be cheaper OTC. If pregnant - try “bug busting” If asthma, eczema or areas of broken skin on the scalp? – use aqueous preparations

Alcoholic Preparations Malathion 0.5% in alcoholic base Rub 0.5% preparation into dry hair and scalp, allow to dry naturally, remove by washing after 12 hours, repeat once at interval of 7 days. 50ml per person Phenothrin 0.2% in basis containing isopropyl alcohol 69.3% (Full Marks lotion) apply to dry hair, allow to dry naturally; shampoo after 2 hours, comb wet hair

Aqueous preparations Malathion 0.5% in aqueous base Rub 0.5% preparation into dry hair and scalp, allow to dry naturally, remove by washing after 12 hours, repeat once at intervals of 7 days. Phenothrin 0.5% in an aqueous basis (Full Marks liquid) apply to dry hair, allow to dry naturally; shampoo after 12 hours or next day, comb wet hair

Bug Busting This requires the use of a plastic detection comb and hair conditioner. The methods typically involve meticulous combing with the detection comb (probably for at least 30 minutes each time) over the whole scalp at 4-day intervals for a minimum of 2 weeks.

Transmission Transmission of head lice requires close contact Head lice can only survive for 48 hours off the scalp. The eggs can survive for up to 10 days off the scalp, but will not hatch at room temperature. Transmission can occur directly via close contact, or indirectly via hats, combs and brushes or scarves. Soft toys and blankets are also vehicles for transmission in schools. Epidemics often sweep through classrooms. It is sensible to inspect the hair of classmates and family members if infestation is found.

Head Lice References: Prodigy, BNF and NHS Direct 2002