بسم الله الرحمن الرحيم Head Lice By: Rawan Ghniemat 2013

Cause: Head lice are small wingless insects (Pediculus humanus capitis) that live on and suck blood from the scalp.

Infestation may remain unnoticed for several weeks until an allergic response to lice saliva begins to cause intense itching, or perhaps until parents are alerted to an epidemic at their child’s school. Adult lice may live for up to several weeks.

Methods of transmission: Infection is spread by direct head-to-head contact, and possibly by transfer through contact with infected hairbrushes, hats, pillows, etc., although lice cannot survive for long away from the scalp.

Incidence: Most occur in school student. The condition is most common in children aged 4–11 years and is more common in girls than boys; anybody can be infected, however. The length or state of cleanliness of the hair makes little difference to the likelihood of becoming infected.

Signs and symptoms: 1.The most common sign is head scratching. 2.Skin redness around the back of the neck and above the ears. The lice can be identified by direct examination using comb then looking at hair through a magnifying glass. The lice appear as tiny brownish gray spot that are difficult to see, But the whitish silver eggs are more likely to seen than the lice.

Skin redness around the back of the neck:

Treatment: There are three steps in treating hair and body lice : 1.Treat the lice and nits by pediculicide agent. 2.Control the symptoms of itching. 3.Clean the environment of potential lice and nits.

insecticides (pediculocides) are used for the eradication of head lice,in presentations including aqueous lotions, a shampoo and a cream rinse. Head lice can also be removed by a mechanical method – wet combing or ‘bug busting’ – without the use of any chemical-based preparations.

Pediculosis agent: OTC product : 1.Pyrethrin with piperonyl butoxide. 2.Permethrin. 3.Dimethicone. Prescription : 1.Malathion. 2.Lindane.

 Pyrethrin with piperonyl butoxide : Safe and effective for head and pubic lice. Pyrethrin is derived from the flowers of chrysanthemum. It is necessary to reply the Pyrethrin within 7-9 days of first application.  Piperonyl butoxide : enhances the pediculicide effect of pyrethrin by suppressing the oxidative degradation mechanisms of the lice. Thus the contact time of pyrethrin is increased.

Direction for use : Apply the product, undiluted, to until it is entirely wet. Allow the product to remain on the head for 10 min. Rinse through with warm water. Dry the area. Comb hair with fine toothed comb to remove the dead lice and eggs.

S/E : 1.Contact dermatitis. 2.Allergic reactions ( allergic rhinitis, asthmatic attack ) because it is derived from chrysanthemum.

 Permethrin : The synthetic version of pyrethrin. It is rapidly absorbed across the insect cuticle and exert their action on the sodium channels of louse nerve axons, causing initial excitement and then paralysis. It is indicated for the treatment of head lice only.

Administration : Permethrin is available as a cream rinse. It is applied after the hair has been shampood. The hair is towel-dried, and cream rinse is applied in sufficient quantity to coat the scalp and hair fully. The preparation is rinsed off after 10 minutes and the hair wet combed. permethrin cream rinse is avoided in pregnancy and during breastfeeding.

Trade names : 1.ZEHU ZE (teva) 2.Lice nock (jepharm) 3.Tic tac (BJP).

 Dimethicone: Derived from polydimethylsiloxane. Inert, non toxic and non flammable. Dimethicone makes hair shiny. Dimethicone is silicon oil,which coats and smothers the lice causing their death either by suffocation or dehydration. Hedrin : ( dimethicone 4% )

Malathion: Malathion is an organophosphorus compound. It is a potent cholinesterase inhibitor, preventing the breakdown of acetylcholine and interfering with neuromuscular transmission in the head louse, paralysing it and preventing it from feeding. Malathion is oil-soluble and is absorbed by a process of passive diffusion through the lipid coat of both insect and egg; achieving a lethal dose depends on the concentration of the product and the duration of contact. It is safe for use at low concentrations.

Administration: Aqueous solutions are rubbed gently into the scalp until all the hair and scalp is thoroughly moistened; application should extend to the neck area and behind the ears. Treatment failure often occurs because the insecticide does not reach all of the scalp. The solution is left on for 12 hours, usually overnight, and the hair is then shampooed in the normal way. The hair should be combed with a fine-toothed comb while it is still wet, to remove dead and dying lice from the scalp. A second application after 7 days is recommended to kill any lice emerging from eggs that may have survived the initial treatment.

There are no contraindications to the use of malathion, apart from known sensitivity. Preparations are not contraindicated in pregnant or breastfeeding women, although manufacturers recommend caution. Malathion preparations may affect permed, coloured or bleached hair. The only reported side-effect is very rare skin irritation.

Products: Aqueous lotions (0.5%) – Derbac-M liquid. – Quellada M liquid. Both products are licensed for use in patients aged from 6 months.

Piperonyl Butoxide 2.0% w/w, Malathion 0.25% w/w, Permethrin 0.5%w/w

Product selection points : There is no clear evidence that any one insecticidal pediculocide is significantly more effective than another. Dimethicone lotion appears to be effective and safe for use for everyone. Two applications of pediculocide 1 week apart is now recommended as standard treatment. * Head-lice products should not be used for prophylaxis, as they are usually not effective and their use in this way encourages the development of resistance.

 OTC treatment failure : 1.Failure to follow product instructions. 2.Non compliance with nit removal. 3.Head – lice drug resistance.

 Facts about head lice: Hygiene and hair length are not contributing factors. Head lice don’t fly and jump from person to person Head lice don’t carry other disease. Head lice cannot be contracted from animals. Hair does not fall out as a consequence of infestation. Head lice infestation can occur at any time of year.

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