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Headlice and Scabies

Headlice and Scabies. Danae Bixler, MD, MPH Infectious Disease Epidemiology. Lice. Objectives. Understand Diagnosis Standard therapy regimens Life cycle and implications for treatment Resistance Alternative therapies Reasons for treatment failure Management of the environment.

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Headlice and Scabies

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  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 DiagnosisPediatrics, 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 (cdc.gov)

  5. Characteristics of Presumed Headlice Specimens Submitted for IdentificationPediatr Infect Dis J, 2000; 19:689-693.

  6. Accuracy of Headlice Diagnosis by ProfessionPediatr Infect Dis J, 2000; 19:689-693.

  7. OTC Pediculocides (Safe)(CDC; Pediatrics, 2007; 119:965-974; Pediatrics, 2002; 110:638-643; Mayo Clin Proc, 2004; 79:661-666)

  8. Prescription Pediculocides(CDC; Pediatrics, 2007; 119:965-974)

  9. Life Cycle Considerations Am J Manag Care. 2004; 10:S264-S264 Egg laid Eyespot Egg Hatches Egg-laying adult 4 days 3-8 days 8.5-11 days 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.

  10. Life Cycle Considerations (2)(CDC: Am J Manag Care. 2004; 10:S264-S264) 7-8 days 3-4 days 3-4 days 3-4days • 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

  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 AgentsPediatrics, 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. Alternative Agents (2)Pediatrics, 2002; 110:638-643Mayo Clin Proc, 2004; 79:661-666. • 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

  15. Alternative Agents (3) Pediatrics, 2002; 110:638-643 • “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

  16. OtherPediatrics, 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 RemovalAm 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 RemovalBMJ, doi:10.1136/bmj.38537.468623.EO (published 5 August 2005) • 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 RemovalPediatrics, 2002; 110:638-643Skin 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 (cdc.gov)

  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

  28. Objectives • Understand • Scabies diagnosis • Treatment considerations • Environmental control • Outbreak management

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

  30. Scabies LesionsBMJ, 2005; 331:619-622. • Common: papules, vesicles, pustules, nodules • Diagnostic: burrows • Confusion: scratching, secondary infection, eczema

  31. Scabies LesionsCleaveland Clinic J Med, 2008; 75:474-478. • Papules • Excoriations • Burrows • Nodules

  32. Norwegian (Crusted) ScabiesClin Microbiol Rev, 2007; 20:268-279.

  33. Atypical ScabiesN Engl J Med, 2006; 345:1718-27.

  34. DiagnosisAm 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

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

  36. Scabicides (Prescription) (CDC, N Engl J Med, 2006; 354:1718-1727)

  37. Scabicides (Prescription)(CDC, N Engl J Med, 2006; 354:1718-1727)

  38. 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

  39. 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

  40. Environmental Management(CDC) • Insecticide sprays and fumigants NOT recommended • Mites do not survive more than 3 days away from human skin

  41. 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

  42. Dairyman’s Itch (Sarcoptesscabeivar. bovis)Clin Infect Dis, 2007; 45:352, 395.

  43. Summary

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