1	What’s Eating You-Update on Head Lice and Scabies Bernard Cohen, M.D. Director of Pediatric Dermatology Johns Hopkins Children’s Center Dermatlas.org
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3	Head Lice Eating You? Social stigma Anxiety, paranoia Families spend $160,000,000/year Products range from $10-28/person/rx Most recommend 2 rx/person
4	Lice-Historical Perspective Lice in existence for several million years Documented in writing for sevaral thousand 560 species of blood sucking lice-only in mammals Insects in order Anoplura, only 2 genera infest humans: Pthirus, Pediculus 3 species in humans: P. humanus capitis, P. humanus humanus, Pthirus pubis
5	Head Lice-Historical Peersepctive Exodus 8:17 Aaron”stretched out his hand with his rod and smote the dust of the earth, and it became lice in men and beast.” Identified in Egyptian, N American Indian mummies Aztecs offered to gods Young women in Siberia threw at men as sign of affection Tonga-catching and eating of parents lice sign of respect Medieval Swedes used lice to select mayor
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12	Head Lice-Epidemiology Endemic in US, incidence ? Rising No area free-prevalence in schools <1%-40% All races x Afro-Americans, Africans not spared (adaptations of claws or egg laying anatomy in African organism?) Risk factors-brown, red hair; female?; length not factor Girls>boys>women>men Not vector for any serious infection (unlike body lice)
13	Head Lice-Problems With RX No Good studies of safety or efficacy Rx agents limited Variable ovicidal activity Treatment failures
14	Head Lice-Resistance? Numcuoglu KY, Hemingway J, Miller J, et al. Permethrin resistance in the head louse Pediculus capitis from Israel. Med Vet Entomol 1995;9:427-32 Burgess IF, Peock S, Brown CM, et al. Head lice resistant to pyrethroid insecticides in Britain. Br Med J 1995;311:752(letter)
15	Head Lice-More on Resistance Downs AM, Stafford KA, Harvey I, Coles GL. Evidence for double resistance to permethrin and malathion in head lice. Br J Dermatol 1999;141:508-11. Meinking TL et al. Are head lice becoming selective in their resistance. Arch Dermatol 2002;138:220-8.
16	Head Lice-Resistance Science Genetic mutations in human lice At least 2 different pathways Hemingway J, et al. Pyrethroid resistance mechanisms in the head louse P. capitis from Israel. Med Vet Entomol 1999;13:89-96. Lee SH, et al. Molecular analysis of Kdr-like resistance in permethrin resistant strains of head lice P. capitis. Pest Biochem Physiol 2000;66:130-43.
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18	Head Lice-Our Study Learned how to collect critters Bioassay for crawlers (knock down time) Technique for studying nits Infrastructure for accessing students Decreased sensitivity to various components of pediculicide Body louse model not adequate Further study necessary
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20	Approved Agents Permethrin 1% cream rinse (Nix) Few studies Residual effect Resistance Chrysanthemum allergy Pyrethrum with piperonyl butoxide (RID, A200) shampoo Few Studies No residue Resistance Ragweed allergy
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23	Approved Agents • Lindane 1% shampoo Poor ovicidal activity Safety issues in children Resistance • Malathion 0.5% lotion (Ovide) High ovicidal activity Poor cosmetic acceptability Flammable Residual effect
24	Unconventional Rx Q 3-4 day Nix 12-16 days Permethrin 5% cream Carbaryl 0.5% Petrolatum, hair gel Trimethoprim/sulfa Ivermectin Professional nit pickers
25	Possible New Rx Compounds that interfere with glue Compounds that repel female mites from laying eggs on hair shaft Agents that coat hair shaft and restrict oxygen transfer (Burkhard CN. J Am Acad Dermatol 2005;53:129-33)
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27	Harvard Panel-1999 Transmission at home No nit policy disruptive Home grooming and exams Second treatment Ovide best ovicidal but expensive, inflammatory
28	10 Rules for Lousy Schools Failure of effective agents Viable residual nits Reexposure (Elston, Cutis 1999) Enlist school nurse Examine for nits/lice Remove nits (Licemeister comb, Step 2, Vinegar) Attention to fomites
29	More Rules Repeat rx at 7-10 days Confirm nit free/fomite control Off-label agents for resistance Prevent resistance Rotate agents Remove nits Control fomites/contacts Multi-drug rx
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35	Scabies in Babies-Epidemiology All ages, races, socioeconomic groups May be lower in Afro-Americans Endemic and “epidemic” Chronic infestation in poor countries Widespread in N America, Europe
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38	Scabies-Etiology Sarcoptes scabiei var. humanis Class Arachnida Female .3 X .4 mm, secretes special substance Lays 3 eggs/day, hatch in 2-3 days, 3 nymph stages Female life span 4-6 wweeks, burrows @ .5-5 mm/day, lays up to 50 eggs Adult survives 24-36 hours off host Nymph survives 2-5 days off host Symptoms from host reaction
39	Scabies-Diagnostic Clues Insidious onset Noctural pruritus Consistent cutaneous eruption Pleomorphic lesions Epidemiology
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42	Scabies-Traditional Rx Permethrin 5% cream Sulfur ointment 2-5% Lindane 1% lotion and cream Crotamiton 10% lotion and cream
43	Scabies Rx-What’s New? Class of compounds from Streptomyces avermitilis avermectins Avermectin B1 modified to ivermectin Macrocyclic lactone similar to macrolides Good antihelminthic-used for sarcoptic mange and heart worms in pets Approved in US for human onchocerciasis
44	Scabies-Ivermectin (Meinking, Taplin. The treatment of scabies with ivermectin. N Eng J Med 1995;333:26-30) 2 groups one comprised of normal hosts and a second with HIV were treated with a single 200 ug/kg dose of ivermectin. Results suggest that this is a safe, easy, effective Rx for scabies. Comment: There were failures requiring reRx and combination Rx
45	Scabies-Ivermectin (Trujullo. Topical ivermectin: a new successful Rx for scabies. Pediatr Dermatol 2001;18:63-6) 6 complete families-12 adults, 20 1-10 yo 1% ivermectin solution in propylene glycol Applied twice in 1 week All cleared, no irritation Low cost effective Rx
46	Scabies-Ivermectin (Usha. A comparative study of oral ivermectin and topical permethrin in the Rx of scabies. J Am Acad Dermatol 2000;42(2pt2):236-30) 85 pts randomized to 200ugm/kg ivermectin v overnight application of permethrin F/U 1, 2, 4, 8 weeks Ivermectin 1 dose = 70% cure 2 doses = 95% Permethrin 1 dose = 97.8% cure
47	Scabies-Ivermectin Effective safe drug (but not as good as permethrin?) Useful in special circumstances (where hygiene is issue, pt incapacitated, no good support care) Two Rx of combination Rx probably necessary
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49	More on Ivermectin Use in treating head lice? Oral Rx may be effective Unreported open label S Am study shows that topical shampoo effecive against crawlers and nits Our experience with cutaneous larva migrans
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