Pubic lice

• Alternative Names

  Pediculosis - pubic lice; Lice - pubic; Crabs

• Causes, incidence, and risk factors

  Pubic lice are known as Phthirus pubis. Lice infestation is found mostly in adolescents.

  Transmission generally occurs during sexual activity. However, it also can occur through physical contact with contaminated objects such as toilet seats, sheets, and blankets. Some women have gotten pubic lice while trying on bathing suits at a store.

  Other types of lice include:

  • Body lice (Pediculus humanus corporis)
  • Head lice (Pediculus humanus capitis)

  Risk factors include:

  • Being sexually active
  • Having multiple sexual partners
  • Having sexual contact with an infected person
  • Sharing bedding or clothing with an infected person
• Symptoms
  • Eggs (nits) or actual adult lice may be seen
  • Itching in area covered by pubic hair (often gets worse at night)
  • Skin reaction that is bluish-gray in color
  • Sores (lesions) in the genital area due to bites and scratching
• Signs and tests

  An examination of the outer genital area typically reveals small gray-white oval eggs (nits) attached to the hair shaft. It may also reveal adult lice. The health care provider might also see scratch marks or signs of an infection such as impetigo.

  Because pubic lice may cause an eye infection (blepharitis) in young children, their eyelashes should be examined with a high-powered magnifying glass for evidence of lice.

  Adult lice may be easily identified under the microscope. Their crab-like appearance is the reason that pubic lice are referred to as "the crabs."

• Treatment

  Pubic lice are best treated with a prescription wash such as Elimite or Kwell:

  • Thoroughly work the shampoo into the pubic hair and surrounding area for at least 5 minutes.
  • Rinse well.
  • Comb the pubic hair with a fine-toothed comb to remove eggs (nits). Applying vinegar to pubic hair before combing may help loosen nits, but the hair should be dry when applying the shampoo.

  A single treatment is all that is usually needed. If another treatment is recommended, it should be done 4 days to 1 week later.

  Over-the-counter medications for the treatment of lice include Rid and Nix. Malathione lotion is another treatment option.

  While you are treating pubic lice, wash all clothing and linens in hot water. Items that cannot be washed may be sprayed with a medicated spray or sealed (suffocated) in plastic bags and not used for 10 - 14 days. It is important for all intimate contacts to be treated at the same time.

  People with pubic lice should be evaluated for other sexually-transmitted diseases at the time of diagnosis.

• Expectations (prognosis)

  The proper treatment, including thorough cleaning, should get rid of the lice.

• Complications

  The constant scratching and digging can cause the skin to become raw, and secondary infections may develop.

• Calling your health care provider

  Call for an appointment with your health care provider if:

  • You or your sexual partner has symptoms of pubic lice
  • You try over-the-counter lice treatments and they are not effective
  • Your symptoms continue after treatment
• Prevention

  Avoid sexual or intimate contact with infected people. If you are sexually active, use safe sex practices to avoid getting lice.

  Good personal hygiene is always recommended. If possible, avoid trying on bathing suits while you are shopping. However, if you must try them on, be sure to wear your underwear. This may prevent transmission.

• References

  Jacobson CC, Abel AA. Parasitic infestations. J Am Acad Dermatol. 2007;56:1026-1043.

Review Date: 12/2/2009

Reviewed By: A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz. Previously reviewed by Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network (10/11/2008).