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Pediculosis (Lice)

para>Lindane: FDA black box warning of severe neurologic toxicity (use only when first-line agents have failed). The National Pediculosis Association strongly advises against using lindane at all.

GENERAL MEASURES

  • Head lice: Clean items that have been in contact with the head of the infected individual within 48 hours.
  • Wash all bedding, towels, clothes, headgear, combs, brushes, and hair accessories in hot water (60 °C).
  • Vacuum furniture and carpets
  • Seal any personal articles that cannot be washed in hot water, dry cleaned, or vacuumed in a plastic bag and store for at least 2 weeks.
  • Examine and treat household members and close contacts concurrently.
  • Insecticide sprays are not necessary.
  • Pubic lice: Avoid sexual activity until both partners are successfully treated.
  • Nit and egg removalRemove eggs that are within 1 cm of the scalp to prevent reinfestation.After treatment with shampoo or lotion, eggs and nits remain in the scalp or pubic hair until mechanically removed. Hair conditioner facilitates nit removal.Eggs and nits are best removed with a very fine nit comb.

Pediatric Considerations

  • Avoid synergized pyrethrin and permethrin in infants <2 months of age. Avoid benzyl alcohol, topical ivermectin, and spinosad in children <6 months of age; and avoid malathion in children <2 years of age.
  • Lindane: not recommended in patients <50 kg

Pregnancy Considerations

Permethrin, synergized pyrethrin, malathion, spinosad, and benzyl alcohol are pregnancy Category B. Lindane and topical ivermectin are Category C.

ADDITIONAL THERAPIES

  • For "difficult to treat " cases of head lice, oral ivermectin 400 ¼g/kg (not approved by the FDA for lice), given twice at a 7-day interval, is superior to topical 0.5% malathion lotion (4,5)[B]
  • Ivermectin: 200 ¼g/kg PO repeated in 10 days or 300 ¼g/kg PO repeated in 7 daysShould not be used in children <15 kg; pregnancy Category CNot approved by the FDA for lice
  • Dual therapy with 1% permethrin and oral trimethoprim/sulfamethoxazole (TMP/SMX) only for cases of multiple treatment failures or suspected cases of lice-related resistance to therapy (TMP/SMX is not approved by the FDA for lice).
  • Permethrin 5% cream (Rx) is not FDA approved for lice and is unlikely to be effective for lice that are resistant to 1% cream rinse (1)[B].

COMPLEMENTARY & ALTERNATIVE MEDICINE

Head lice

  • Dry-on, suffocation-based pediculicide: Cetaphil lotionApply thoroughly to hair, comb, dry with hair dryer, shampoo after 8 hours.Repeat once a week until cured, up to a maximum of three applications.Not approved by the FDA for lice
  • Dimethicone 4% lotion: Apply to hair for 8 hours; repeat in 1 week (not approved by the FDA for lice).
  • No home remedies (e.g., vinegar, isopropyl alcohol, olive oil, ylang ylang oil, mayonnaise, melted butter, and petroleum jelly) have been proven effective to treat head lice infestations.
  • Herbal shampoos and pomades have not been evaluated in clinical trials and are not approved by the FDA for lice.
  • Lavender oil and tea tree oil have been implicated in triggering prepubertal gynecomastia in boys and should not be used to treat lice.
  • Electronic louse combs have not proven effective and are not approved by the FDA.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Children may return to school after completing topical treatment, even if nits remain in place. No-nit policies are not necessary.

Patient Monitoring

Drug resistance should be suspected if no dead lice are observed in 8 to 12 hours after treatment.

PATIENT EDUCATION

  • National Pediculosis Association: http://www.headlice.org/
  • CDC: http://www.cdc.gov/parasites/lice/
  • http://www.guideline.gov/content.aspx?id=46429&search=lice

PROGNOSIS

  • With appropriate treatment, >90% cure rate
  • Recurrence is common, mainly from reinfection or treatment nonadherence. Resistance to synthetic pyrethroids is increasing.

COMPLICATIONS

  • Poor sleep due to pruritus
  • Persistent itching may be caused by too frequent use of the pediculicide.
  • Missed school; social stigma
  • Secondary bacterial infections
  • Body lice can transmit typhus and trench fever.

REFERENCES

11 Devore CD, Schutze GE. Head lice. Pediatrics. 2015;135(5): e1355 " e1365.22 Burgess IF. Current treatments for pediculosis capitis. Curr Opin Infect Dis. 2009;22(2):131 " 136.33 Gunning K, Pippitt K, Kiraly B, et al. Pediculosis and scabies: treatment update. Am Fam Physician. 2012;86(6):535 " 541.44 Chosidow O, Giraudeau B, Cottrell J, et al. Oral ivermectin versus malathion lotion for difficult-to-treat head lice. N Engl J Med. 2010;362(10):896 " 905.55 Feldmeier H. Treatment of pediculosis capitis: a critical appraisal of the current literature. Am J Clin Dermatol. 2014;15(5):401 " 412.

ADDITIONAL READING

  • Cole SW, Lundquist LM. Spinosad for treatment of head lice infestation. Ann Pharmacother. 2011;45(7 " 8):954 " 959.
  • Durand R, Bouvresse S, Berdjane Z, et al. Insecticide resistance in head lice: clinical, parasitological and genetic aspects. Clin Microbiol Infect. 2012;18(4):338 " 344.
  • Pariser DM, Meinking TL, Bell M, et al. Topical 0.5% ivermectin lotion for treatment of head lice. N Engl J Med. 2012;367(18):1687 " 1693.

SEE ALSO

Arthropod Bites and Stings; Scabies

CODES

ICD10

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

ICD9

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

SNOMED

  • 81000006 Pediculosis capitis (disorder)
  • 25188002 Pediculosis corporis (disorder)
  • 71011005 Infestation by Phthirus pubis (disorder)
  • 414618002 louse infestation (disorder)
  • 187211004 Mixed pediculus infestation

CLINICAL PEARLS

  • School-based no-nit policies are not necessary because empty nits may remain on hair shafts for months after successful eradication.
  • Proper product application is essential; consider improper product application when assessing treatment failure.
  • Prevalence of resistant infestations is increasing, so if no dead lice are observed in 8 to 12 hours after treatment, suspect resistance and use an alternative agent.
  • Routine retreatment on day 9 is recommended for nonovicidal products (permethrin and synergized pyrethrin).
  • With all treatment options, reinspect hair after 7 to 9 days and, if live lice are detected, repeat treatment on day 9.