Pediculosis (Lice)

Clinical Case

Case 1

  • 15-year-old healthy female high school student
  • No significant past medical history
  • Review of systems is noncontributory
  • Presents for management of 6 weeks’ history of an intensely pruritic eruption on the scalp and neck
  • Recent history of a louse infestation outbreak on school athletic team
  • Denies recent travel, new cosmetics for hair or skin

Initial evaluation

  • Healthy appearing female teenager
  • Scattered erythematous macules and excoriated papules on the neck; several lice and egg casings are noted in the scalp hair
  • No evidence of superinfection is present
  • Complete skin and hair examination does not reveal additional sites of infestation
  • Diagnosis: head lice
  • Recommend permethrin 1% lotion applied on days 0, 7, and 15 for 10 minutes to clean, non-conditioned, towel-dried hair
  • Topical triamcinolone 0.1% lotion applied b.i.d. to the scalp and posterior neck to alleviate pruritus
  • Follow-up in 9 days

Follow-up evaluation

  • Several lice, eggs, and nits noted, raising concern for permethrin-resistance
  • Malathion 0.5% is prescribed (day 0 and repeat application on day 9)
  • Follow-up in 2 weeks (no evidence of lice infestation is found)