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

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

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

Accuracy of Headlice Diagnosis by Profession Pediatr Infect Dis J, 2000; 19: DiagnosticianNumber of Submissions Number of Subjects with Evidence of: Extinct and/or active Infestation Active Infestation Relative Nurse Self Physician Teacher

OTC Pediculocides (Safe) (CDC; Pediatrics, 2007; 119: ; Pediatrics, 2002; 110: ; Mayo Clin Proc, 2004; 79: ) 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

Prescription Pediculocides (CDC; Pediatrics, 2007; 119: ) GenericBrandConsiderations Malathion lotion 0.5% Ovide Pediculocidal and partially ovicidal Retreat if live lice are 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

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 days days Egg-laying adult

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

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

Arch Dermatol, 2002; 138:

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

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: Mayo Clin Proc, 2004; 79:

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:

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

Other (2) Pediatrics, 2006; 118: 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

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

Manual Removal BMJ, doi: /bmj 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”

Challenges of Manual Removal Pediatrics, 2002; 110: Skin Therapy Letter, 2006; 11 (cdc.gov) 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

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

Treatment Considerations / Environmental Interventions CDC, Pediatrics, 2002; 110: 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.

Environmental Interventions (2) CDC, Pediatrics, 2002; 110: 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.”

School Interventions Pediatrics, 2002; 110: 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

Treatment Failure

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

“… 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

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

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

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

Scabies Lesions Cleaveland Clinic J Med, 2008; 75: Papules Excoriations Burrows Nodules

Norwegian (Crusted) Scabies Clin Microbiol Rev, 2007; 20:

Atypical Scabies N Engl J Med, 2006; 345:

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

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

Scabicides (Prescription) (CDC, N Engl J Med, 2006; 354: ) 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

Scabicides (Prescription) (CDC, N Engl J Med, 2006; 354: ) 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

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

Treatment Considerations (2) (CDC, N Engl J Med, 2006; 354: ) 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

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

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

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

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