Headlice

=Headlice=

What it is
Head lice, //Pediculus humanus// var. //capitis// are ectoparasites that feed exclusively on human blood. They cannot jump or fly and live their entire life (about a month) on the head of their host, often being concentrated towards the back of the head and behind the ears

Symptoms
//Most cases asymptomatic// - Pruritus, resulting from sensitisation to louse salivary or faecal antigens - Persistent scratching can cause the development of lesions which may give rise to secondary infections and/or swollen lymph glands.

Diagnosis of lice infestation should be made by observing a live louse on the scalp. This can be achieved by the [|‘conditioner and comb’] method: 1. Apply conditioner to dry hair aiming to cover each hair from root to tip with a layer of conditioner. 2. Detangle the hair using an ordinary comb. 3. Immediately comb the hair with a fine tooth comb. The best comb for this are combs with cylindrical metal teeth, not flat teeth. However, plastic nit combs with conditioner are also very effective at detecting and removing climbers with conditioner, but far less effective for eggs. 4. Wipe the conditioner off the fine tooth comb onto a paper tissue and look for lice and eggs. 5. Repeat the combing for every part of the head at least 5 times. 6. Also examine the comb for lice and eggs.

Head lice are 1-4mm in length (approximately the size of a sesame seed), and their colour ranges from nearly colourless (when they hatch) to reddish brown (after feeding).

How to Treat
//Only treat if headlice or eggs have been found//. //In theory, all lice and eggs are killed on a single application. However, studies suggest that some eggs survive, therefore a further application 7 days later is now recommended.//

Pyrethrins with piperonyl butoxide (e.g., Banlice Mousse and Pyrenel Foam). Pyrethrin is an insecticide and piperonyl butoxide potentiates its action by inhibiting its metabolism.

Permethrin e.g., Quellada Head Lice Treatment, Pyrifoam Lice Breaker (contain 1% permethrin) and Orange Medic Plus (contains 0.2% permethrin – this strength has not been evaluated for efficacy), is a synthetic pyrethroid with pediculicidal and ovicidal properties.

Maldison (malathion) e.g., KP 24, HL 7, is an organophosphate with pediculicidal and ovicidal activity. It is available as a 0.5% lotion and a 1% shampoo which may be used in conjunction with the lotion.

Non-drug treatment options include the 'bug-busting method' (wet combing), which involves combing wet hair with a fine toothed comb every 3-4 days for 2 weeks. This removes all the lice as they hatch and ensures that none reach maturity and lay the next generation of eggs. It has shown to have a cure rate of 38% compared with 78% for malathion. Children were nearly three times as likely still to have headlice afterwards.

Other advice
- Head lice do not prefer dirty hair and an infestation should not be seen as a reflection on personal hygiene, home environment or social status. - Prevention of lice using insecticides is not advocated. - Other people who have been in close contact should be traced and thoroughly checked - Parents need to be reassured that the presence of egg shells does not mean treatment failure. (Egg shells are not removed by using insecticides)

//It is believed that the surfactant not only triggers the immersion reflex by increasing the ability of the water to effectively coat the lice, thereby blocking their breathing apparatus, but it also covers the lice with a film or coating of surfactant which blocks their breathing apparatus upon evaporation of the solvents from the composition. Once dried, this film encases the louse, blocking its ability to breathe until the dried agent is removed, such as would typically occur by resolubilization.//
 * How conditioner 'stuns' headlice**

Additional Resources
[|Self-care Card - Headlice] [|Facts behind the Fact Card - Headlice and Scabies] [|JCU - Headlice] [|Better Health - Headlice: Treatment and Control] [|mydr.com.au - Headlice] [|Parenting and Child Health - Headlice] [|Health NSW - Treatment]: contains pictures of the 'comb and conditioner method' [|Driable Pediculostatic Agents]: highly detailed explanations about how conditioner stuns headlice