Rosen & Barkin's 5-Minute Emergency Medicine Consult (516 page)

Pubic lice may also indicate sexual abuse in children

DIAGNOSIS

• Head lice:
  
  • Dandruff
    
  • Pruritus
    
  • Often asymptomatic
    
• Body lice:
  
  • Pruritus
    
  • Excoriation particularly at belt lines or seams of clothing
    
• Pubic lice:
  
  • Intense pruritus, worse at night
    

• 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
    
• 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 trunk
    
  • Pus or serum stains on clothing
    
• 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
    

• Careful history and physical exam
  
• Universal precautions
  

• 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 ∼1 mm long but wider body than head or body louse
  

No imaging indicated

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

TREATMENT

Not applicable for routine cases

• 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 common
      
    • Pyrethrin (Rid) also has low toxicity but is less effective
      
  • 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
      
  • Temperature >131°F (55°C) for >5 min kills eggs, nymphs, and mature lice
    
• Body lice:
  
  • Wash and dry bedding and clothing using hot cycles
    
  • Apply topical pediculicide cream or lotions from chin to toes
    
• 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
    

• Antipruritics:
  
  • Diphenhydramine: 25–50 mg PO (peds: 5 mg/kg/d) q6h
    
  • Hydroxyzine: 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 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
    

• Pediculicides:
  
  • Ivermectin 0.5% lotion (Sklice): Apply to dry hair and scalp and rinse after 10 min
    
  • Spinosad 0.9% suspension (Natroba): Apply to dry hair and rinse after 10 min; repeat in 7 days if necessary
    
  • Ivermectin tablets (Stromectol): 200–400 μg/kg PO once; repeat in 7–10 days later
    
    • Use 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

Extensive bacterial superinfection; systemic hypersensitivity reaction with cardiorespiratory compromise

• 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
  

• 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
  

• 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 common
  
  • 2nd-line agents are more expensive
    

• 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

• 132.0 Pediculus capitis [head louse]
  
• 132.1 Pediculus corporis [body louse]
  
• 132.9 Pediculosis, unspecified
  

BASICS