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TRANSCRIPT
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Focus Session U031:
Infestation Situations: Updates on Bothersome Bugs
Raegan D. Hunt, MD, PhD
Assistant Professor of Dermatology & Pediatrics
Chief, Pediatric Dermatology
Texas Children’s Hospital
Baylor College of Medicine
Raegan Hunt, MD, PhD
Focus Session U031 : Infestation Situations: Updates on Bothersome Bugs
DISCLOSURESPfizer: Advisory Board – Consulting Fee
DISCLOSURE OF RELATIONSHIPS WITH INDUSTRY
Educational Objectives
Diagnose skin infestations and insect bite reactions more effectively
Describe emerging treatment resistance trends among mites and insects that cause dermatologic disease
Develop effective treatment plans for skin infestations
“Secret” Objectives
Disgust you with “creepy crawly” photos
Make you itch!
Compel you to check the hotel room mattress frame!
Head lice: pediculosis capitis
• CDC estimates 6‐12 million head lice infestations annually in the US• Most headlice infestations are among ages 3‐11 years
• More common among girls than boys
• Estimated economic burden of lice • ~ $1 billion/ year (2004)
• Other impacts of head lice infestation• Scalp itch and irritation• Secondary infection associated with scratching• Missed school/work• Social disruption• Embarrassment
“Social Media Lice”: Selfie Spread?
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Head lice
http://www.liceremovallosangeles.com
“The Days of Our Lice”Lice
~ 100 eggs per pair
The “Facts of Lice”
• Head lice die in 1–2 days without feeding
• Nits die within a week and cannot hatch if they are not near scalp
Hygiene recommendations• Machine wash and dry
• clothing and bed linens worn 2 days before treatment
• Seal un‐washable items in plastic bag for 2 weeks
• Soak combs and brushes in hot water (≥ 130°F) for 5 minutes
• Vacuum floor and furniture around where infested person sits/sleeps
• Counsel patients not to share hair accessories
The “Infestation Situation”
Super Head Lice Head Lice
Vs.
Gellatly KJ, et al. J Med Entomol, Mar 2016.
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Pediculosis capitis: “Super lice”
Red states: 100% of tested lice resistantOrange states: 50‐90% of tested lice resistantYellow state: 0 % of tested lice resistantWhite states: data not analyzed yetBlue states: data not collected yet
• Pyrethroid resistant
• “over the counter” treatments ineffective
Yoon, et al. American Chemical Society, August 2015.
Pyrethroid resistant head lice
• Knockdown resistance (kdr) mutations• Point mutations in α‐subunit gene of voltage‐sensitive sodium channel (VSSC) are functionally responsible for the nerve insensitivity
• 138 lice collection sites in 48 U.S. states from 2013 – 2015
• Not tested: Alaska, West Virginia
• 132/138 sites (95.6%) had a mean % resistance allele frequency (RAF) of 100%
• Five sites (3.7%) had intermediate values• Only a single site had no mutations (0.0%)‐ Michigan
• Forty‐two states (88%) had a mean % RAF of 100% Gellatly KJ, et al. J Med Entomol, Mar 2016
Over the counter: lice treatments
Pyrethroids
• Pyrethrins• Pyrethroid extracts from the chrysanthemum flower• Not ovicidal; repeat treatment on day 9• Avoid use in people allergic to chrysanthemums or ragweed
• Approved ages ≥ 2 years
• Permethrin lotion 1% • synthetic pyrethroid
• similar to naturally occurring pyrethrins• Not ovicidal; repeat treatment on day 9• Approved ages ≥ 2 months
Malathion lotion 0.5%
• FDA approval 1999• Organophosphate pesticide
• Inhibits cholinesterase activity
• Partially ovicidal• Single application + nit combingadequate for most patients
• Apply to dry hair• Leave on 8‐12 hours then rinse
• May be irritating
• Flammable
• Approved for ≥ 6 years of age• Malathion resistance reported among head lice in UK
Spinosad 0.9% topical suspension
• FDA approved 2011
• Biochemical insecticide produced by soil bacteria
• bacterial species Saccharopolyspora spinose• Found in crushed sugar cane
• Neurotoxic to lice• Targets nicotinic acetylcholine receptors of the insect nervous system resulting in hyperactivation
• Ovicidal
• Apply to dry hair, leave on scalp 10 min
• Effective as a single application on dry hair without nit combing
• Re‐treatment typically not needed (re‐treat if live lice seen in 1 week)
• Approved for children ≥ 6 months
Ivermectin lotion 0.5%
• FDA approval 2012• Neurotoxic to lice
• Activates glutamate‐gated chloride channels in nerves• Death by cell hyperpolarization and paralysis
• Not ovicidal• Kills nymphs! (newly hatched lice) • Apply to dry hair, leave on 10 min then rinse• “nit picking optional”• Typically effective as a single application on dry hair without nit combing
• Approved for children ≥ 6 months
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Benzyl alcohol lotion 5%
• FDA approved 2009• Non‐neurotoxic pesticide• Aromatic alcohol
• Kills lice via asphyxiation
• Not ovicidal• Apply to dry hair, leave on 10 min
• Nit comb
• REPEAT treatment on day 9
• Approved for ages 6 months‐ 60 years
Meinking TL, et al. Pediatr Dermatol. 2010 Jan‐Feb;27(1):19‐24
Benzyl alcohol lotion 5%
Hair length Volume needed for treatment
Active ingredient Class/mechanism Ovicidal? RetreatmentNeed?
Potential side effects/FDA approval
Cost (approximate)
Malathion 0.5% lotion
Organophosphate “Partially Yes” Not“usually” *
‐Flammable! (8‐12 hours on scalp)‐Irritating!Approved age ≥ 6 years
$221.70 (60 ml)
Spinosad 0.9% suspension
Antimicrobial biochemical produced by soil bacteria; neurotoxic to lice
YES! NO! * Approved ≥ 6 months $246.10 (120 ml)
Ivermectin 0.5% lotion
Anti‐parasitic; neurotoxic to lice
No, but kills nymphs
NO! * Approved ≥ 6 months $297.60 (120 ml)
Benzyl alcohol 5% lotion
AlcoholNot a neurotoxic pesticide
No YES Approved ≥ 6 months $ 181.30 (8 fl oz bottle)‐ may need 1‐6 bottles depending on hair length
Pyrethrins Pyrethroid extract from crysanthemum
No YES Avoid if allergic to chrysanthemums or ragweedApproved ≥ 2 years
$6‐16 (60‐120 ml)
Permethrin 1% lotion
synthetic pyrethroid similar to naturally occurring pyrethrins
No YES Approved ≥ 2 months $8‐14 (60‐120 ml)
Lindane 1% shampoo/lotion
Organochloride No YES Black Box warningSecond line due torisk of neurotoxicity
$125 (60 ml)
More Natural Approaches?
Nit pickingProfessional nit picking
• Cost range ~$75‐100/hour
• Estimated 3 total treatments needed
• Treatments ~1‐1.5 hours each
• Estimated minimum: $225 AND 3 hours of “family time”
• “Louse calls”• Discrete in‐home concierge nit‐picking
• Some Health Flex savings accounts cover nit picking
Home nit picking
• Instructions for families on Headlice.org hosted by the
National Pediculosis Association (non‐for profit)
• Modern male head lice have smaller claws compared to ancient specimens
• Nit picking practices may have resulted in selective advantage to smaller grip
Nunez H, et al. Micron. 2017 Apr;95:31‐34.
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AirAllé® Lice Treatment
• Heated air• Cooler temperature and faster flow than blow drier
• Estimated 1 hour treatment• 30 minutes with device
• 30 minutes of nit picking
• One treatment needed
• Cost approximately $170
• FDA approved for ages ≥ 4 years
FDA approved device for lice treatment Essential Oil Alternatives?
• Eucalyptus oil ‐Leptospermum petersonii(EO/LP) blend showed superiority to pyrethrins and piperonyl butoxide
• LP‐ “lemon tee tree oil”
• EO/LP‐ twice as effective • (83% vs 36%, P < 0.0001)
• EO/LP‐ 100% pediculocidal with 1 application
• EO/LP‐ 100% of lice and eggs in vitro
• Adverse events: limited to transient burning, itching, stinging
Greive KA and TM Barnes, Australas J Dermatol. 2017 Mar 7.
Pediculosis capitis re‐“cap”
“Super head lice!” In about ½ of the states, head lice show 100% resistance to pyrethroids over the counter now
Several FDA approved head lice medications available Malathion 0.5% lotion Ivermectin 0.5% lotion Spinosad 0.9% suspension Benzyl alcohol 5% lotion
FDA approved head lice air treatment device AirAllé®
Human pediculosis
Head louse Body louse
Bonilla D, et al. PLoS Pathog 9(11): 2013
Body louse Pubic louse
Clinical Presentation- Body lice
• Uncommon infestation
• War, poverty, homeless populations
• Louse lives and lays eggs in fabric fibers, especially seams of clothing
• Urticarial papules develop as response to saliva injected with feeding
• Dry, scaly, lichenified skin with extensive infestation
• Can transmit infectious diseases
• Epidemic typhus
• Trench fever
• Relapsing fever
“Louse blouse”: body lice
Irizarry E, et al. Arch Dermatol. 2007 May;143(5):682.
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Body lice
http://www.aocd.org/resource/resmgr/ddb_high/pediculosis_corporis_1_high.jpg
•Treatment•Replace clothing
• Body lice live and lay eggs in the clothing• Only come to skin to feed
• Improved hygiene and living conditions• Access to regularly cleaned clothing• Spread by close human‐human contact
CDC
Pubic lice• Commonly called crab lice
• Easily transmitted during sexual activity
• Usually found in pubic hair but can occur on perianal, proximal thigh, axilla and course facial hair‐ including eyebrows and eyelashes
• Pruritus and crawling sensation in affected areas
• Macula cerulea‐ bluish macules in areas of lice bites
• Regional lymphadenopathy can occur
CDC
http://www.soc.ucsb.edu/sexinfo/sites/default/files/crabs.jpg
Pubic Lice: treatment
• Pubic area: Permethrin 5% cream overnight to affected hairy areas, repeat in 1 week
• Eyelashes/eyebrows: • Nit comb or manual removal (if few nits)• Ophthalmic‐grade petrolatum ointment (prescription) to the eyelid margins 2–4 times a day for 10 days• Yellow mercuric oxide 1%‐ 4x daily x 14 days• Pilocarpine 4% gel‐ twice daily for 10 days• Fluorescein eyedrops 20%‐ single application
• Consider oral ivermectin days 1 and 8 if topical therapy fails or extensive eyelash involvement (off label use)
Taplin D, Meinking TL. Infestations. In: Schachner LA, Hansen RC (eds). Pediatric Dermatology. 4th edn. Edinburgh: Mosby, 2011:1141–80
Micali and Lacarrubba. N Engl J Med 2015; 373:e35
Pediculosis Pearls
• Lice move by crawling- they CANNOT hop or fly!
• Pets do not play role in transmission of human lice
• Consider sexual abuse if pubic lice in young or adolescent children
• Nits in hair alone do not indicate contagiousness
• “super lice” are common now; consider your local resistance data
• Large, live head lice: possible re-infestation• Head lice of different sizes: possible resistance
A mighty fine mite…
Stoffle NN, Cohen PR. Images in clinical medicine. Sarcoptes scabiei infestation. N Engl J Med. 2004;350:e20
Scabies • Highly infectious, pruritic and common parasitic infestation• Sarcoptes scabiei mite
• Human to human transmission
• Fertilized female mite burrows into epidermis depositing eggs and fecal pellets (scybala)
• Eggs hatch in several weeks, larvae grow into mites
• Delayed Type IV hypersensitivity occurs about one month after exposure
• Initial localized minor itching changes to severe, widespread pruritus
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Scabies: Clinical Presentation
• Pruritic papules on abdomen, hands, wrists, elbows, axilla, genitalia and interdigital web spaces
• Nodules can occur from exaggerated hypersensitivity reaction
• Children:
• Involvement of face and scalp seen more frequently than in adults
• Infants:
• Scaly papules and vesicles in occluded areas and palms, soles
• Eczematous eruptions of face, scalp and trunk
Dermoscopy: “hanglider or jet” at end of burrowDermnetnz.org
Crusted Scabies
• More severe and less common
• Compromised immunity or inability to scratch leads to massive mite infestation
• Individuals are highly contagious
• Can result in complications from secondary bacterial infection
Scabies: Diagnosis
• May be based upon clinical findings alone• Contact with persons with similar pruritic eruptions supports diagnosis
• Definitive diagnosis from microscopy• Scraping of non-excoriated burrow
• Mineral oil prep• Consider potassium hydroxide prep to help denature some
keratin
• Presence of mites, eggs or scybala confirm the diagnosis
Treatment: scabies
• Asymptomatic “carriers” in household are common• Treat entire household at same time
• Permethrin 5% cream overnight; repeat overnight in 1 week• Infants and elderly: head to toes (include scalp and face)• Others: neck to toes
• Sulfur (5‐10%) compounded in petrolatum x 3 consecutive nights
• Wash clothing, linens and towels used within the previous week in hot water and dry with high heat or store in a sealed bag for 10 days
• “post‐scabietic” pruritus may linger 2‐4 weeks after successful treatment
Scabies Pearls: Think scabies if….
• Severe nocturnal pruritus
• Multiple family members with same complaint
• Pruritus with interdigital web involvement
• Inflammatory nodules on genitals
• Vesiclopustules on acral skin in infants
• “Dermatitis” that fails treatment
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History
• No fever
• No pain
• + intense itch
• Early lesions start as “bumps”
• Has had episode like this about 1 year ago
• No mucosal involvement
Bullous arthropod bite reaction
Goodheart HP, MD. Goodheart's Photoguide of Common Skin Disorders, 2nd Edition. Philadelphia: Lippincott Williams & Wilkins, 2003
Diagnostic clues
• Very itchy
• Localized preferentially on extremities
• Happened before around 1 year ago (e.g. “the same season of year ”)
Bullous arthropod
Treatment recommendations
• Antihistamines
• Cool compresses
• Clobetasol 0.05% oint applied twice daily to pruritic areas on extremities
Prevention
• Protective clothing
• Insect repellant
Bullous arthropod
Cannot distinguish the offending insect from skin findings
• Mosquitos• Fleas• Ants• Bed bugs• Black flies• Midges
Bullous bite reaction to bed bugs
Leverkus M, et al. Bullous Allergic Hypersensitivity to Bed Bug Bites Mediated by IgE against Salivary Nitrophorin. Journal of Investigative Dermatology (2006) 126, 91–96
Bullous arthropod bite reaction
• Bullous arthropod bite reactions have been noted in CLL
• 10 cases• Bullous reaction to an arthropod bite
• Reaction may be secondary to the underlying lymphoproliferative disorder
(Rosen, LB et al, JAAD, 1986, 943–950)
Mayes RC, et al, Am J Trop Med Hyg. Sep 2010; 83(3): 447
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Bullous Insect Bite Reaction Pearls:
• Itchy!
• History of recurrence annually with season change
• Mostly on exposed skin, extremities
• Parents find diagnosis hard to accept
• Treatment: Antihistamines, Clobetasol oint, cool compresses
• Prevention: protective clothing, insect repellant
• In adults, consider underlying diagnosis of CLL
THANK YOU