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Headlice and Scabies Danae Bixler, MD, MPH Infectious Disease Epidemiology.

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Presentation on theme: "Headlice and Scabies Danae Bixler, MD, MPH Infectious Disease Epidemiology."— Presentation transcript:

1 Headlice and Scabies Danae Bixler, MD, MPH Infectious Disease Epidemiology

2 Lice

3 Objectives Understand – Diagnosis – Standard therapy regimens – Life cycle and implications for treatment – Resistance – Alternative therapies – Reasons for treatment failure – Management of the environment

4 Challenges of Diagnosis Pediatrics, 2002; 110:638-643 ( Gold standard = live louse Travel 6-30 cm/min. Viable eggs Within 1 cm of scalp Develop eyespot Confusion Dandruff Scabs Dirt Other insects

5 Characteristics of Presumed Headlice Specimens Submitted for Identification Pediatr Infect Dis J, 2000; 19:689-693. IdentityN% Lice (trophic forms or live/dead/hatched eggs36459.3 Other arthropods (springtails, book lice, beetles, mites, caddisflies, thrips, bedbugs) 335.4 Debris (dandruff, fibers, dirt, scabs, epidermal matter) 21635.2 Knotted hair10.2 TOTAL614100.1

6 Accuracy of Headlice Diagnosis by Profession Pediatr Infect Dis J, 2000; 19:689-693. DiagnosticianNumber of Submissions Number of Subjects with Evidence of: Extinct and/or active Infestation Active Infestation Relative20473.047.1 Nurse18970.431.7 Self9217.412.0 Physician4216.711.9 Teacher1485.750.0

7 OTC Pediculocides (Safe) (CDC; Pediatrics, 2007; 119:965-974; Pediatrics, 2002; 110:638-643; Mayo Clin Proc, 2004; 79:661-666) GenericBrandConsiderations Pyrethrins + piperonyl butoxide A-200 Pronto R&C Rid Triple X Paralysis of live lice Retreat in 9-10 days Tx failure may be common (resistance) Do not use in ragweed / chrysanthemum allergic Permethrin lotion 1% Nix Paralysis of live lice May kill newly hatched lice for several days after treatment Retreat in 9-10 days Tx failure may be common (resistance) Not approved age < 2 years Conditioners / dilution reduce effect

8 Prescription Pediculocides (CDC; Pediatrics, 2007; 119:965-974) GenericBrandConsiderations Malathion lotion 0.5% Ovide Pediculocidal and partially ovicidal Retreat if live lice are present @ 7-9 days Can be irritating / avoid contact with eyes Flammable Age 6 and older Do not use if pregnant or nursing Lindane shampoo 1% -- Paralysis of louse Neurotoxicity Do NOT use in persons weighing less than 110 lbs, elderly, pregnant or nursing women … Single use / 4 minute application time

9 Life Cycle Considerations Am J Manag Care. 2004; 10:S264-S264 Period of vulnerability to pediculocides All first-line agents act on louse neurological system ‘Eyespot’ = developed nervous system Perfect ovicide / pediculocide At day 0 kills eggs>4 days old, nymphs and adults Second treatment at day 7. Eyespot Egg laid Egg Hatches 4 days3-8 days8.5-11 days Egg-laying adult

10 Life Cycle Considerations (2) (CDC: Am J Manag Care. 2004; 10:S264-S264) 3 molting cycles after hatching Third instar nymph most resistant Freshly molted nymph most susceptible Exposed nymph can molt / receive sublethal dose Pediculocide persistence => resistance 7-8 days 3-4 days

11 Ranking of Pediculocides (2000) (Am J Manag Care, 2004; 10:S264-S268) Malathion 0.5% (OVIDE) Undiluted permethrin 1% (Nix) Diluted permethrin 1% Pyrethrin (A-200) Pyrethrin (RID) Lindane AAP recommended

12 Arch Dermatol, 2002; 138:220-224

13 Alternative Agents Pediatrics, 2002; 110:638-643 Crotamiton (10%) – Prescription lotion – FDA licensed for scabies – Effective when applied for 24 hours in a single study – No safety data

14 Trimethoprim-sulfamethoxazole – Oral agent not licensed for lice – Kills symbiotic bacteria in louse gut(?) – Increased efficacy with permethrin 1% Limited data Authors: consider in case of treatment failure – Rare side effects Ivermectin – licensed for scabies treatment – 200 µg orally ; repeat in 10 days – Neurological risk factors – Do not use in children < 15 kg – Topical formulation has also been tested Alternative Agents (2) Pediatrics, 2002; 110:638-643 Mayo Clin Proc, 2004; 79:661-666.

15 Alternative Agents (3) “Natural” agents – Limited efficacy data – No safety data Occlusive agents – E.g., petrolatum jelly, mayonaise – Limited or no data – Asphyxiation of lice versus mechanical removal – Repeat weekly for 4 weeks Pediatrics, 2002; 110:638-643

16 Other Pediatrics, 2004; 114: e274-e279; Skin Therapy Letter, 2006; 11(10) Nuvo (Cetaphil gentle skin cleanser) lotion – Apply lotion, comb out hair. Dry with a hand-held hairdryer. Shampoo in 8 hours. – Accepted by parents and children – 97% lice free after 3 treatments (parent-submitted samples) – 94% lice free at 6 months (parental report) – No control group

17 Other (2) Pediatrics, 2006; 118:1962-1970. 30 minute treatment with ‘Lousebuster’ – Operator combs hair and directs heat at the base of hair sections 80% lice mortality 10 of 11 subjects lice-free at 1 week Small numbers / no control group / limited follow up

18 Manual Removal Am J Manag Care, 2004; 10:S264-S268 Randomized trial; N= 95 Treated with permethrin Second treatment at day 8 if lice observed 1/3 given Licemeister comb and instructed in proper daily use

19 Manual Removal BMJ, doi:10.1136/bmj.38537.468623.EO (published 5 August 2005) AnalysisBug Buster kit (15 days)Pediculocide (5 days) Total# (%) curedTotal# (%) cured Participants with complete outcome data 5632 (57%)709 (13%) Intent to treat analysis 6232 (52%)719 (13%) Single-blind, randomized trial: Permethrin 1% or malathion 0.5% versus ‘Bug buster’ kit with no additional instruction Outcome = detection of live lice 5 days for pediculocide 15 days for “Bug Buster”

20 Challenges of Manual Removal Pediatrics, 2002; 110:638-643 Skin Therapy Letter, 2006; 11 ( Painful, tedious Operator-dependent May decrease Diagnostic confusion Need for additional treatment Prioritize removal of nits within 1 cm of scalp 1:1 vinegar:water wash

21 Transmission (CDC; Pediatrics, 2002; 110:638-643) Head-to-head contact Fomites – Hats – Hair-care items – Bedding Lice die within 24-48 hours off the scalp

22 Treatment Considerations / Environmental Interventions CDC, Pediatrics, 2002; 110:638-643 Treat – Infested person – His/her bedmate Evaluate household contacts and treat – Live lice or – Nits within 1 cm of scalp Wash (hot water 130°F) clothing, bedding, hair care products used within 48 hours.

23 Environmental Interventions (2) CDC, Pediatrics, 2002; 110:638-643 Vacuum furniture, carpet, car seats, etc. Non-washable items – Dry clean – Store in plastic bags for 2 weeks Do not use pediculide spray “Herculean cleaning measures are not beneficial.”

24 School Interventions Pediatrics, 2002; 110:638-643 Use common sense: – Maintain confidentiality – Child can return to school when treated – Evaluate risk to other children Evaluation of children with head-to-head contact (?) Notification of parents (?) “No-nit policies” are discouraged

25 Treatment Failure

26 Treatment Failure Am J Manag Care, 2004; 10:S260-S263, Pediatrics, 2002; 110:638-643 Misdiagnosis? Nonadherence? Reinfestation? Appropriate product? Resistance? – Possible: Live lice present 2-3 days after treatment – Certain: Live lice present after 2 correctly applied treatments

27 “… one learns to live with the inevitability of lice in kids as one does with fleas in cats.” Br J Gen Pract, 2004; 54:643


29 Objectives Understand – Scabies diagnosis – Treatment considerations – Environmental control – Outbreak management

30 Typical Locations for Scabies Lesions Am Fam Physician, 2004; 69:341-8

31 Scabies Lesions BMJ, 2005; 331:619-622. Common: papules, vesicles, pustules, nodules Diagnostic: burrows Confusion: scratching, secondary infection, eczema

32 Scabies Lesions Cleaveland Clinic J Med, 2008; 75:474-478. Papules Excoriations Burrows Nodules

33 Norwegian (Crusted) Scabies Clin Microbiol Rev, 2007; 20:268-279.

34 Atypical Scabies N Engl J Med, 2006; 345:1718-27.

35 Diagnosis Am Fam Physician, 2004; 69:341-8, N Engl J Med, 2006; 354:1718-27, Clinical diagnosis (J Fam Pract, 2007) – Pruritis – Clinical lesions in at least two places Skin scrapings Punch biopsy Role uncertain – Epiluminescence microscopy – Noncomputed dermoscopy

36 Dermatologist vs. Generalist … Eur J Dermatol, 2005; 15:171-5.

37 Scabicides (Prescription) (CDC, N Engl J Med, 2006; 354:1718-1727) GenericBrandInformation Permethrin cream 5% Elimite Drug of choice Approved > 2 months of age Safe / effective Two applications one week apart may be necessary Crotamiton lotion 10% and Crotamiton cream 10% Eurax Crotan Approved in adults Safe Frequent failure

38 Scabicides (Prescription) (CDC, N Engl J Med, 2006; 354:1718-1727) GenericBrandInformation Lindane lotion 1% -- FDA approved for scabies Not first-line treatment Neurological side effects Don’t use to treat children, persons weighing less than 110 pounds, pregnant or nursing mothers … IvermectinStromectol Oral antiparasitic Not FDA approved for scabies Safe / effective (limited data) Reported effective for Norwegian scabies Two doses 2 weeks apart

39 Treatment Considerations (CDC, Arch Fam Med, 2000; 9:473-4) Treat – Infested person – Household and sexual contacts – Persons who have had skin-to-skin contact e.g., hugging / lifting Application (where): – Adults: neck to toes – Infants and young children: entire head and neck to toes

40 Treatment Considerations (2) (CDC, N Engl J Med, 2006; 354:1718-27) Application (how) – Apply to clean body – Leave on recommended time – Wash off and put on clean clothes Retreatment – Itching still present at 2-4 weeks – New burrows or pimple-like lesions continue to occur

41 Environmental Management (CDC) WhatUsed by WhomManagement Items used within 3 days: Bedding Clothing Towels Infested person Household and sexual contacts Persons with skin-to-skin contact Wash in hot water and dry in a hot dryer OR Dry clean OR Seal in a plastic bag for at least 72 hours Insecticide sprays and fumigants NOT recommended Mites do not survive more than 3 days away from human skin

42 Outbreaks Nosocomial: patients and staff Recommendations: – Contact precautions 24 hours after treatment 10 days after treatment of crusted scabies – Make a secure diagnosis Use a dermatologist Search for atypical cases – Identify infested persons Identify their contacts within 2-4 weeks … – Treat infested persons and contacts all at once Patients and staff

43 Dairyman’s Itch (Sarcoptes scabei var. bovis) Clin Infect Dis, 2007; 45:352, 395.

44 Summary ConsiderationHeadliceScabies DiagnosisLive lice Nits within one cm of scalp Burrows Pruritis Typical findings in two or more body sites MisdiagnosisCommon Drug of choicePermethrin 1% (malathion) Permethrin 5% TreatInfested persons and bedmates Infested persons and contacts Retreat10 days7 days or if pruritis continues at 2-4 weeks Treatment failureCommonContinued allergic reaction > resistance

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