pedikulosis

Pediculosis and PhthiriasisPediculosis and Phthiriasis

Pediculus humanus capitis Pediculus humanus capitis

( head lice)( head lice)

Pediculus humanus corporis Pediculus humanus corporis

(body lice)(body lice)

Phthirus pubis (pubic lice)Phthirus pubis (pubic lice)

PediculosisPediculosis

Head lice are most commonly found in Head lice are most commonly found in school children, with the most vulnerable school children, with the most vulnerable age being 4-11 years oldage being 4-11 years old

No significant sex differencesNo significant sex differences Do not discriminate rich or poor Do not discriminate rich or poor Do not have any preference towards dirty Do not have any preference towards dirty

or cleanor clean

PrevalencePrevalence Pediculosis has a worldwide distributionPediculosis has a worldwide distribution In epidemiologic school surveys in different In epidemiologic school surveys in different

countries found to be :countries found to be : 15% in France (Combescot, 1990),15% in France (Combescot, 1990), 33.7% in Australia (Speare and Buettner, 1999),33.7% in Australia (Speare and Buettner, 1999), 40% in Taiwan (Fan et al., 1991) 40% in Taiwan (Fan et al., 1991) 28.3% in the U.K. (Downs et al., 2000)28.3% in the U.K. (Downs et al., 2000) USA : has risen steadily over the last 3 decades USA : has risen steadily over the last 3 decades

(Guenther, L, Medscape)(Guenther, L, Medscape)

MorphologyMorphology and life cycle and life cycle Fam : Pediculidae, Fam : Pediculidae,

ordo : Anoplura ordo : Anoplura

Class : InsectaClass : Insecta Consist of head, thorax and abdomenConsist of head, thorax and abdomen 3 pair of legs, with claw (to 3 pair of legs, with claw (to cling to and cling to and

crawl through human hair) , wingless crawl through human hair) , wingless

A permanent ecto-A permanent ecto-

parasiteparasite blood-sucking insects blood-sucking insects Die after 10 days Die after 10 days

starvationstarvation Incomplete Incomplete

metamorphosismetamorphosis

Eggs : laid at the base of hairs, about ½ -Eggs : laid at the base of hairs, about ½ -inch from the scalpinch from the scalp

A female louse can lay as many as 5 - 6 A female louse can lay as many as 5 - 6 eggs each day (50-100 eggs in its lifetime)eggs each day (50-100 eggs in its lifetime)

The eggs attach to the human hair with a The eggs attach to the human hair with a material like super gluematerial like super glue

Eggs hatch after 7-10 days. Eggs hatch after 7-10 days. 

Morphology and habitatMorphology and habitat

P.humanus P.humanus capitiscapitis

P.humanus P.humanus corporiscorporis

Phthirus pubisPhthirus pubis

Live on Live on human hairhuman hair

clothing and clothing and beddingbedding

Pubic hair, eye Pubic hair, eye lash, moustache lash, moustache and beard and and beard and armpitarmpit

Difficult to differentiate: Difficult to differentiate: muscle of the thorax of muscle of the thorax of P. P. humanus corporishumanus corporis clearly clearly seenseen

Rounded body Rounded body (crab louse)(crab louse)

Phthirus pubis ( crab louse)

Pathogenesis & symptoms Pathogenesis & symptoms

P.humanus P.humanus capitiscapitis

P.humanus P.humanus corporiscorporis

Phthirus Phthirus pubispubis

Asimptomatic, Asimptomatic, itching, itching, papules. papules. Scratching : Scratching : secondary secondary infectioninfection

- plica - plica palonicapalonica

Itching/ Itching/ pruritus pruritus

(play role as (play role as vector of vector of epidemic epidemic typhustyphus, trench fevertrench fever, louse borne louse borne relapsing relapsing fever)fever)

• Itching/ Itching/ pruritus pruritus

at pubic areaat pubic area• eggs on eye eggs on eye lash can disturb lash can disturb eye visioneye vision

Source: Logical Image (Skin sight)

Pediculosis corpoPediculosis corporisrisPhthiriasis

DiagnosisDiagnosis

Evidence of eggs/nits, nymph or Evidence of eggs/nits, nymph or

adults adults

Favourite places : behind the ears / at the Favourite places : behind the ears / at the

nape of necknape of neck

‘‘Detection combing’ Detection combing’

Source: DermAtlas (www.stanford.edu)

TreatmentTreatment

Head lice :Head lice : Combing Combing and manual and manual

TreatmentTreatment

Insecticide :Insecticide : Shampoo/ lotion / mousse of Shampoo/ lotion / mousse of

permetrin 1%, benzen permetrin 1%, benzen hexachloride, pyrethrioid basedhexachloride, pyrethrioid based

Can be repeated after 10-14 daysCan be repeated after 10-14 days Cutting hair if neededCutting hair if needed

Treatment (cont’d)Treatment (cont’d)

Pediculosis humanus corporis: change Pediculosis humanus corporis: change and wash clothing frequentlyand wash clothing frequently

Body lice : bedding should be Body lice : bedding should be fumigatedfumigated

Pubic lice : as recommended for head Pubic lice : as recommended for head licelice

EpidemiologyEpidemiology Transferred from person to person Transferred from person to person

through comb, mats, bedding through comb, mats, bedding Phthirus pubisPhthirus pubis : : sexual activitysexual activity P.humanus corporisP.humanus corporis : mostly in : mostly in

cool climate; poor personal cool climate; poor personal hygiene hygiene