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Pediculosis, Emergency Medicine

Basics

Description

- Pediculus corporis (body louse): - Associated with poverty, poor hygiene, and overcrowding - Live in clothing and transfer to human host for feeding - Can live up to 30 days off of human - Related to bed bugs

- Examine hair for adult lice and nits: - Nits are cemented on hair shafts and are not easily removed - Head lice and pubic lice infestation is confirmed by differentiating nits from scales, hair casts, and other easily brushed-off artifacts - Empty nits are not diagnostic of active infection

- Pubic lice: - Occasional urticaria with typical flare/wheal formation - May infest eyelashes and scalp in children - Characteristic bluish macules (maculae ceruleae) appear infrequently on trunk and thighs - Prefer the perineum and pubic areas - Inguinal adenopathy

- All agents require reapplication in 7 " 10 days if further adult lice or nits noted - Remove nits with fine-toothed comb - Examine all members of household; treat infested individuals - Change clothing and machine wash and dry (using hot cycles) all clothing, towels, linens, and headgear: - Vacuum floors and furniture - Wash combs and brushes in hot water for 10 " 20 min or coat with pediculicide for 15 min and wash

- Pubic lice: - Topical pediculicide applied to hairy areas of chest, axilla, and groin - Remove nits with fine-toothed comb - Treat sexual contacts simultaneously - Wash and dry bedding and clothing using hot cycles - Treat eyelash involvement with topical petrolatum twice daily for 9 days

- Pediculicides: - Permethrin 1% cream rinse (Nix): Apply to scalp and hair, rinse after 10 min; reapply in 7 " 10 days if needed - Pyrethrin/piperonyl butoxide (Rid): Apply to scalp and hair, wash after 10 min; repeat in 7 " 10 days; avoid in patients with ragweed allergies - Benzyl alcohol lotion 5% (Ulesfia lotion): Apply to scalp and hair, wash off after 10 min; repeat in 7 days - Mercuric oxide ophthalmic ointment 1%: Use for louse infestation of eyelids: Apply QID for 14 days

  • Infestation by organisms that live in close association with host
  • Bites are painless
  • Signs and symptoms result from host response to saliva and anticoagulant injected during feeding
  • Transmitted by direct contact and fomites (inanimate objects)
  • Head lice are transmitted by head-to-head contact:
  • Head lice are more common in children and females
  • Pubic lice are transmitted by sexual contact
  • Obligate human parasites cannot survive away from hosts >7 " 10 days

Etiology

Infestation by:

  • Pediculus capitis (head louse):Most commonAll socioeconomic groups
  • Pediculus corporis (body louse):Associated with poverty, poor hygiene, and overcrowdingLive in clothing and transfer to human host for feedingCan live up to 30 days off of humanRelated to bed bugs
  • Phthirus pubis (pubic or crab louse)

Pubic lice may also indicate sexual abuse in children

Diagnosis

Signs and Symptoms

History

  • Head lice:DandruffPruritusOften asymptomatic
  • Body lice:PruritusExcoriation particularly at belt lines or seams of clothing
  • Pubic lice:Intense pruritus, worse at night

Physical Exam

  • Examine hair for adult lice and nits:Nits are cemented on hair shafts and are not easily removedHead lice and pubic lice infestation is confirmed by differentiating nits from scales, hair casts, and other easily brushed-off artifactsEmpty nits are not diagnostic of active infection
  • Scalp and posterior neck erythema, scaling, and excoriated papules:May lead to pyoderma, posterior cervical lymphadenopathy, and bacterial superinfection
  • Body lice are observed only in very heavy infestation; infestation is confirmed by finding nits in clothing seams:Linear excoriations of neck and trunkPus or serum stains on clothing
  • Pubic lice:Occasional urticaria with typical flare/wheal formationMay infest eyelashes and scalp in childrenCharacteristic bluish macules (maculae ceruleae) appear infrequently on trunk and thighsPrefer the perineum and pubic areasInguinal adenopathy

Essential Workup

  • Careful history and physical exam
  • Universal precautions

Diagnosis Tests & Interpretation

Lab

  • Nits may be visualized under low-power microscopy along hair shafts. They are <1 mm long:Fluorescent under Wood lamp
  • Mature lice are 3 " 4 mm long
  • Pubic louse ¢ ¼1 mm long but wider body than head or body louse

Imaging

No imaging indicated

Differential Diagnosis

  • Scabies
  • Contact or allergic dermatitis
  • Seborrheic dermatitis
  • Bed bugs (Cimicidae)

Treatment

Pre-Hospital

Maintain universal precautions

Initial Stabilization/Therapy

Not applicable for routine cases

Ed Treatment/Procedures

  • Oral antihistamines and topical steroids may help pruritic symptoms of all lice infestations
  • Head lice:Topical pediculicidal agents:Permethrin 1% cream rinse (Nix) is a reasonable agent; it has low toxicity and cost and is ovicidal; however, resistance is becoming more commonPyrethrin (Rid) also has low toxicity but is less effectiveAll agents require reapplication in 7 " 10 days if further adult lice or nits notedRemove nits with fine-toothed combExamine all members of household; treat infested individualsChange clothing and machine wash and dry (using hot cycles) all clothing, towels, linens, and headgear:Vacuum floors and furnitureWash combs and brushes in hot water for 10 " 20 min or coat with pediculicide for 15 min and washTemperature >131 °F (55 °C) for >5 min kills eggs, nymphs, and mature lice
  • Body lice:Wash and dry bedding and clothing using hot cyclesApply topical pediculicide cream or lotions from chin to toes
  • Pubic lice:Topical pediculicide applied to hairy areas of chest, axilla, and groinRemove nits with fine-toothed combTreat sexual contacts simultaneouslyWash and dry bedding and clothing using hot cyclesTreat eyelash involvement with topical petrolatum twice daily for 9 days

Medication

First Line

  • Antipruritics:Diphenhydramine: 25 " 50 mg PO (peds: 5 mg/kg/d) q6hHydroxyzine: 25 mg PO q8h (peds: 12.5 mg/dose q6h)
  • Pediculicides:Permethrin 1% cream rinse (Nix): Apply to scalp and hair, rinse after 10 min; reapply in 7 " 10 days if neededPyrethrin/piperonyl butoxide (Rid): Apply to scalp and hair, wash after 10 min; repeat in 7 " 10 days; avoid in patients with ragweed allergiesBenzyl alcohol lotion 5% (Ulesfia lotion): Apply to scalp and hair, wash off after 10 min; repeat in 7 daysMercuric oxide ophthalmic ointment 1%: Use for louse infestation of eyelids: Apply QID for 14 days

Second Line

  • Pediculicides:Ivermectin 0.5% lotion (Sklice): Apply to dry hair and scalp and rinse after 10 minSpinosad 0.9% suspension (Natroba): Apply to dry hair and rinse after 10 min; repeat in 7 days if necessaryIvermectin tablets (Stromectol): 200 " 400 ¼g/kg PO once; repeat in 7 " 10 days laterUse if 1st-line agents (Nix, Rid, Ulesfia) are not tolerated or effective
  • Antihistamine:Cetirizine (Zyrtec): Age >12 yr, 5 " 10 mg PO (peds: 6 " 11 yr, 5 " 10 mg PO; 2 " 5 yr, 2.5 mg PO) daily
  • Nix is Class B and probably safe in lactation
  • Rid is Class C and probably safe in lactation
  • Ulesfia is Class B but should read package insert; safety unknown in lactation
  • Ivermectin is Class C with safety unknown in lactation
  • Spinosad is Class B but should read package insert for specifics; safety unknown in pregnancy
  • Nix can be used in children >2 mo
  • Rid can be used in children >2 yr
  • Ulesfia can be used in children
  • Ivermectin can be used in children >6 mo
  • Spinosad can be used in children >4 yr

Follow-Up

Disposition

Admission Criteria

Extensive bacterial superinfection; systemic hypersensitivity reaction with cardiorespiratory compromise

Discharge Criteria

  • Mild-to-moderate infestation with absence of significant superinfection or hypersensitivity reaction
  • Children may return to school after initial treatment if repeat therapy is administered in 7 " 10 days
  • Pubic lice are often associated with sexually transmitted diseases; prudent screening is recommended

Follow-Up Recommendations

  • Re-evaluation is necessary to observe if treatment has been successful
  • Case management and/or social services may be required if concern for child well-being

Pearls and Pitfalls

  • Diagnosed by direct visualization
  • Most of the topical agents need to be reapplied in 7 " 10 days because unhatched eggs are not killed
  • Clothing and bedding must be washed and dried at a high heat to eradicate the infestation
  • Lindane is no longer recommended
  • Resistance to Nix and Rid is increasingly more common2nd-line agents are more expensive

Additional Reading

  • Benzyl alcohol lotion for head lice. Med Lett Drugs Ther. 2009;51:57.
  • Chosidow O, Giraudeau B. Topical ivermectin " a step toward making head lice dead lice? N Engl J Med. 2012;367:1750 " 1752.
  • Frankowski BL, Bocchini JA Jr, et al. Head lice. Pediatrics. 2010;126:392 " 403.
  • Gunning K, Pippitt K, Kiraly B, et al. Pediculosis and scabies: Treatment update. Am Fam Physician. 2012;86:535 " 541.
  • Ivermectin (Sklice) topical lotion for head lice. Med Lett Drugs Ther. 2012;54:61 " 63.

Codes

ICD9

  • 132.0 Pediculus capitis [head louse]
  • 132.1 Pediculus corporis [body louse]
  • 132.9 Pediculosis, unspecified
  • 132.2 Phthirus pubis [pubic louse]
  • 132.3 Mixed pediculosis infestation
  • 132 Pediculosis and phthirus infestation

ICD10

  • B85.0 Pediculosis due to Pediculus humanus capitis
  • B85.1 Pediculosis due to Pediculus humanus corporis
  • B85.2 Pediculosis, unspecified
  • B85.3 Phthiriasis
  • B85.4 Mixed pediculosis and phthiriasis
  • B85 Pediculosis and phthiriasis

SNOMED

  • 20848007 Infestation by Pediculus (disorder)
  • 81000006 Pediculosis capitis (disorder)
  • 25188002 Pediculosis corporis (disorder)
  • 71011005 Infestation by Phthirus pubis (disorder)
  • 91566005 Mixed pediculosis