Testing overview
- inspection
- wet and comb hair, remove tangles
- examine under strong light with magnifying glass
- use fine-toothed comb (teeth 0.2 to 0.3 mm apart)
- insert comb near crown at scalp
- comb entire head systematically at least twice
- examine comb after each stroke
Treatment overview
- topical procedures
- optimal pediculicide dependent on local resistance patterns
- universal retreatment recommended in 7 to 10 days if live lice seen
- permethrin 1% applied to towel-dried hair, leave for 10 minutes then rinse
- FDA approved in adults and children ≥2 months old
- recommended by AAP as treatment of choice for head lice
- malathion 0.5% lotion applied to dry hair, then after 8 to 10 hours washed off with shampoo
- FDA approved in adults and children ≥6 years old
- recommended when permethrin resistance suspected
- benzyl alcohol lotion 5% lotion applied for 10 minutes
- FDA approved in patients ≥6 months old
- ivermectin 0.5% lotion applied to dry hair for 10 minutes
- FDA approved in patients ≥6 months old
- other topical treatments
- dimethicone 4% lotion
- spinosad 0.9% topical suspension (FDA approved in patients ≥4 years old)
- pyrethrins with piperonyl butoxide applied to dry hair for 10 minutes
- lindane no longer recommended for use as pediculicide
- occlusive agents may be effective including
- melaleuca plus lavender oil
- coconut plus anise oil
- petroleum jelly
- nit removal
- evidence limited and inconsistent
- nit-removal combs do not appear to be effective adjunct to topical pediculicide
- “no-nit” policies for return to school
- discouraged by AAP and APHA
- may be required for reentry to school or day care based on local regulations
- oral medications
- not approved by FDA for treatment of head lice
- options may include
- trimethoprim-sulfamethoxazole 5 mg/kg twice daily
- oral ivermectin 400 mcg/kg twice 7 days apart
- pediculicide considered effective if lice dead or slowly moving 8 to 12 hours after treatment
Other management
- physical nit removal (evidence for effectiveness limited and inconsistent)
- nit-removal combs do not appear to be effective adjunct to topical pediculicide
Desiccation
- blowing hot air through custom-built hair dryer for 30 minutes reported effective
- desiccation with regular blow-dryer not recommended (due to potential spread)
Treatments not recommended
- head shaving (effective but distressing)
- flammable or toxic substances such as gasoline or kerosene products
- nit-loosening agents (such as vinegar, vinegar-based products, acetone, bleach, vodka, and WD-40)
- topical spray (dyes nits bright pink)
Follow-up
- confirm treatment success 1 to 2 days after final application of pediculicide
- if moving lice of all sizes present, resistance
- if only 1 adult-size louse present, re-infestation
- re-treat with different pediculicide if re-infestation occurs within 1 month
Causes of treatment failure
- misunderstanding/noncompliance instructions
- inappropriate instructions from product/clinician
- misdiagnosis
- inappropriate product used
- failure to re-treat recommended interval
- live eggs not removed
- acquired resistance to pediculicide
- treatments to consider if proven resistance or active infestation documented include
- benzyl alcohol 5% of age > 6 months
- malathion 0.5% if age >24 months
- manual removal via wet combing or occlusive method (such as petroleum jelly or suffocation product) for younger patients, with 2 to 4 treatment cycles
Complications
- secondary bacterial skin infection due to scratching (rare)
Prognosis
- pruritus may persist 7 to 10 days after effective treatment
- current resistance rated unknown
- most children with nits but no active lice do not develop lice
- re-infestation may be common
Contacts of index cases
- screen all household members
- treat if live lice or nits identified within 1 cm of scalp
- consider treating family members who share a bed with index case even if no live lice found
School attendance
- do not restrict children from school due to lie, due to low risk of contagion within classrooms
Dr. Drabkin is a senior clinical writer for DynaMed (www.ebscohost. com/dynamed), a database of comprehensive updated summaries covering more than 3,200 clinical topics, and assistant clinical professor of population medicine at Harvard Medical School.
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