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LICE – IDENTIFICATON & TREATMENT. Pediculosis Capitis - head lice infection or infestation Pediculosis Capitis - head lice infection or infestation Pediculosis.

Dec 27, 2015



Lorraine Fisher
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  • Pediculosis Capitis - head lice infection or infestation Pediculosis Corporis - body lice - usually associated with poor socio-economic conditions i.e. homeless infrequent change of clothing/poor hygiene

  • TransmissionUsually head-to-head contactCan be contracted through the sharing of brushes, hats, scarves, coats, bedding/linens, etc. Obligate human parasite (a parasite organism that cannot complete its life cycle without dependence on its host) cannot be transferred through pets/animals

  • Life CycleMature female can lay 3 6 eggs/day and live for about 1 monthEggs hatch within 6 10 days, maturity reached after another 10 days nits may survive up to 3 weeks after removal from the host


  • Most commonly affects children 3 11 years of age but anyone can be affectedCommon to have outbreaks at schools, dormitories, etcPrevalence - Female > MaleLikely many unreported due to stigma attached to infectionLice prefer a clean environmentFacts

  • Approx. 1 3 mm longFlatWingless 3 sets of legs - insect

  • Signs & SymptomsMost often found on the warmer areas of the head behind the ears & back of head & neckItching common, especially at nightExcessive scratching can cause inflammation and secondary bacterial infectionLice lay eggs or nits, cemented, close to the base of the hair shaftEyelashes (rarely) may be involved as well

  • IDENTIFICATIONLive lice may be detected, but they move very quickly, and shy away from light so detection of live lice may be difficult advantageous to use 2 people to check the infected person - many of those infected will have < 10 organisms present Lice appear sluggish away from the warm scalpUsually 24 hour survival off the host Some recent data suggest for up to 55 hours

  • IDENTIFICATION OF NITSImportant to distinguish nits from other possibilitiesDandruff, residues from gels/lacquers can look like nitsRecent, viable un-hatched eggs are creamy-yellow and very close to the scalp while older nit shells are further away from the scalp and white in colourOval in shape, slightly smaller than a sesame seed, never irregular in shape, fuzzy, or encircle the hair

  • TREATMENTA NIT REMOVAL COMB IS AN EFFECTIVE SCREENING TOOLManual removal may be the most important step, and it is possible to treat head lice with this method alone

  • TREATMENTMainstay of treatment insecticides

  • Lice and other arthropods are killed by these medications blocking nerve impulses causing paralysis and death of the parasite

    Products should be applied to clean, dry hair in sufficient quantity to saturate the hair/scalp (especially behind the ears and the nape of the neck) and left on for 10 minutes, then rinsed.Other treatments, petroleum jelly, kerosene, Tea-tree oil and others are either ineffective or unsafe

  • Nit or egg removal should follow with a fine-toothed nit comb. Soaking the hair and wrapping the scalp with a 50/50 solution of vinegar and water for at least 15 minutesMachine wash (hot) and dry all hats, scarves, coats, bedding, if possible, and dry in dryer on the hot settingFor articles that cannot be cleaned this way, dry clean or seal up in a plastic bag for one week

  • The nit comb, as well as other combs, brushes, barrettes, etc can be soaked in rubbing alcohol for 1 hourClean house room by room by thorough vacuuming (rugs, furniture, floors)All close contacts should be thoroughly screened and treated only if necessaryAfter treatment, person should be checked regularly for any evidence of lice or nitsRe-treatment may be necessary and alternate agents may have to be used - resistance

  • Itching, redness, and inflammation may persist for several days after successful treatment and may not necessarily mean re-application is required

    Even the presence of live organisms several hours after treatment does not indicate that the treatment was unsuccessful; often these parasites take several hours to die after exposure to treatment

  • ALTERNATE TREATMENTElectric battery-powered comb zaps lice Some success Price - $50

  • Centers for Disease Control and Prevention. Parasitic disease information: head lice infestation. Division of Parasitic Diseases. Hansen RC, et al. Guidelines for the treatment of resistant pediculosis. Contemporary Pediatrics 2000 Aug:S1-10. Hipolito RB, Mallorca FG, Zunia-Macaraig ZO, et al. Head lice infestation: single drug versus combination therapy with one percent permethrin and trimethoprim/sulfamethoxazole. Pediatrics 2001;107(3):p.e30. Burson, SC, Permethrin-Resistant Head Lice Pharmacist'sLetter 1999;15(11):151116 Clinical Pharmacology


    ********** Fine-toothed nit comb - make sure all nits are removed or the treatment may fail! 15 minutes of soaking will help dissolve the cement the louse uses to attach the nit to the hair shaft and will facilitate easier removal Plastic bag - wool items, stuffed animals, etc.*After treatment - especially 7 10 days after treatment, as by this time any remaining viable nits may have hatched *Check for evidence of infestation by carefully examining the scalp and the use of a nit comb re-treatment after one week is sometimes required*