Head Lice

Presented by: LEE KIAN CHOY

Introduction  It’s an ectoparasites that feeds on blood and sensitive toward the light  Mostly occurs in school-aged (5-11 y.o) children (girls more prevalent than boys)  Infection are commonly characterized by pruritis caused by feaces antigen or

lice’s saliva (weeks to develop)

 Chronic scratching can lead to excoriation can lead to secondary bacterial

infection

 Nits are normally found in behind ears and neck

Life-Cycle of Head Lice: Able to live up to one month on human heads but can

only survive for up to 2 days away from human An adult female can produce an average of 56 eggs once fertilized Eggs will hatched in 7-10 days of incubation (1cm from scalp) Hatchlings will molts 3 times (9-12 days) to become an adult

Mode of Transmission: Mostly by close contact as head lice are unable to

jump or fly, hence, they clawed/trapeze their way to others hair Example of transmission route: a)Making social contacts (parent-child interaction) b)Shared combs, brushes, towels, clothing, beds and

closets

Note: Head to head contact is by far the most common route of transmission

Insecticide Treatment:

 Permethrin: causes electrochemical abnormalities across the

membranes of excitable cells, leading to sensory hyperexcitability, incoordination and collapse

 Caution: hypersensitivity towards permethrin (chrysanthemums)

: if there is wound on the head : child < 2 y.o (safety has not been demostrated)  pregnancy (category B)  Direction to use: Wash the hair with normal shampoo rinse and

towel dry until the hair is still slightly damp. Apply permethrin to the hair and scalp (avoid contact with eyes). Leave for ten minutes, then wash out thoroughly with water and towel dry. Use a fine toothed plastic comb to remove nits. One application is usually sufficient to kill those lice. To ensure complete eradication examine the scalp after seven to ten days and reapply to clear hatchlings

Insecticide Treatment:

 Pyrethrin: disrupt nerve impulse transmission in lice resulting in

paralysis and death (additional of piperonyl butoxide ONLY potentiate pyrethrin activity)

 Caution: hypersensitivity towards permethrin (chrysanthemums)

: if there is wound on the head : child < 2 y.o (safety has not been demostrated)  pregnancy (category B)  Direction to use: Wash the hair with normal shampoo rinse and

towel dry until the hair is still slightly damp. Apply pyrethrin to the hair and scalp (avoid contact with eyes). Leave for ten minutes, then wash out thoroughly with water and towel dry. Use a fine toothed plastic comb to remove nits. One application is usually sufficient to kill those lice. To ensure complete eradication examine the scalp after seven to ten days and reapply if necessary.

Insecticide Treatment:

 Malathion (lotion): Irreversible cholinesterase inhibitor which is vital

for nerve impulse transmission  Caution: contain flammable alcohol (avoid heat)

: not recommended for kids < 2 y.o : hypersensitivity towards insecticides  pregnancy (category C)  Direction to use: Apply lotion to dry hair & wash hair after 8-12

hours. Use fine-tooth comb to remove dead lice, repeat the procedure after 7 days

Insecticide Treatment:

 Benzyl alcohol 5% lotion: act by closing their respiratory

spiracles results in asphyxiation  Caution: if there is wound on the head

: child less than 6 months old : hypersensitivity towards insecticides  pregnancy (category B)  Direction to use: Apply lotion to dry hair, using enough to

completely saturate scalp and hair (avoid contact with eyes); rinse off with water after 10 min; repeat treatment in 1 wk

Insecticide Treatment:  Gamma Benzene Hexachloride 0.1%: stimulates nervous

system of parasite, causing seizures and death  Caution: if there is wound on the head

: not safe to be used in children : history of seizures  pregnancy (category C)  Direction to use: Apply to dry hair and surrounding areas (avoid

contact with mouth or eyes); allow to set for 4 min, then lather for 4 min and rinse; repeat after 7 days when necessary

Manual Treatment: 10 Day Hair Conditioner Treatment a)Apply plenty of conditioner until saturated and comb

with normal hair comb to remove tangle b)Section the hair to four direction (forward, backward, left & right) with fine-tooth nit comb (one section at a time) c) Wipe the comb with tissue paper and look out for lice or nits (rinse hair after combing) d)Repeats steps above every other day for 10 days e)Check reinfestation once a week for four weeks after the 10 days treatment

Practice Points: 

The following individual should NOT use insecticide head lice treatment: a)Baby under 2 years of age b)Patient with insecticide allergies c) Scalp hypersensitivity d)Pregnant/breast feeding women All insecticides does NOT 100% eradicate head lice

eggs

Wet combing with vinegar can help in removing eggs

that are attached to the hair

Note: Home remedy such as vaseline, mayonnaise & suffocationbased pediculicide lotion has been advocated but insufficient scientific research has been done

Self-Management:  Check among family members to ensure others are not

affected & treat concurrently if affected

 Comb and hair comb/brush should be treated

concurrently with pediculicides or soak in hot water

 Bedding should be laundered in hot water and dry clean  Isolate school-aged children from attending school until

they are properly treated

 Avoid over treating the head lice which can cause

resistance

Note: Disinfecting the furniture is NOT necessary

Self-Management: Prevention: To avoid re-infection of head lice make sure affected family members are treated Comb the hair with hair gel or tie long hair together  Remind child of school age to avoid head to head

contact Shaving the hair can be considered as the most direct

way of eradicating head lice (cosmetic unacceptable)

Thank You

Reference:

http://www.public.health.wa.gov.au/cproot/473/2/He

http://emedicine.medscape.com/article/785248-over

http://pediatrics.about.com/cs/conditions/a/head_lice Australian Medicines Handbook (2007)