Medicine & USMLE

Pediculus humanis and Phthirus pubis (Lice)

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Parasites
  1. Giardia lamblia
  2. Toxoplasma gondii
  3. Entamoeba histolytica
  4. Cryptosporidium
  5. Naegleria fowleri
  6. Trypanosoma brucei
  7. Plasmodium Overview
  8. Plasmodium Disease (Malaria)
  9. Babesia
  10. Trypanosoma cruzi
  11. Leishmania
  12. Trichomonas vaginalis
  13. Enterobius vermicularis (pinworm)
  14. Ascaris lumbricoides (giant roundworm)
  15. Strongyloides stercoralis (threadworm)
  16. Ancyclostoma and Necator
  17. Trichinella spiralis
  18. Trichuris trichiura (whipworm)
  19. Toxocara canis
  20. Onchocerca volvulus
  21. Loa loa
  22. Wuchereria bancrofti
  23. Taenia solium
  24. Diphyllobothrium latum
  25. Echinococcus granulosus
  26. Schistosoma
  27. Clonorchis sinensis
  28. Sarcoptes scabiei (Scabies)
  29. Pediculus humanis and Phthirus pubis (Lice)

Summary

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Key Points

  • Pediculus humanus (head lice)/Phthirus pubis (pubic lice)
    • Characteristics
      • Blood-sucking lice
    • Transmission
      • Head lice
        • Hair-to-hair contact
        • Common among households with  infected children, crowded living quarters
      • Pubic lice
        • Close physical or sexual contact
    • Presentation
      • Intense pruritus with excoriations
        • Crawling sensation
      • Eyelash infection
        • Can cause conjunctivitis
        • Can be caused by both species
      • Pediculus humanus infests scalp and neck
      • Phthirus pubis infests pubic and perianal regions
    • Pathogenesis
      • Females lay nits (eggs) that are attached to the hair
        • Nits > 1 cm away from hair shaft may indicate an old, not active, infection
    • Diagnosis
      • Examine by wet combing hair with a fine-tooth comb
        • Visual inspection of base of hair for nits or (less commonly) live bugs
    • Treatment
      • Permethrin
      • Nit combing (after shampooing with permethrin)