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Head lice

Pediculosis capitis - head lice

 

Head lice are tiny insects that live on the skin covering the top of your head (scalp). Head lice may also be found in eyebrows and eyelashes.

Lice can be spread by close contact with other people.

Causes

 

Head lice infect hair on the head. Tiny eggs on the hair look like flakes of dandruff . However, instead of flaking off the scalp, they stay in place.

Head lice can live up to 30 days on a human. Their eggs can live for more than 2 weeks.

Head lice spread easily, particularly among school children. Head lice are more common in close, overcrowded living conditions.

You can get head lice if:

  • You come in close contact with a person who has lice.
  • You touch the clothing or bedding of someone who has lice.
  • You share hats, towels, brushes, or combs of someone who has lice.

Having head lice causes intense itching, but does not lead to serious medical problems. Unlike body lice, head lice never carry or spread diseases.

Having head lice does NOT mean the person has poor hygiene or low social status.

 

Symptoms

 

Symptoms of head lice include:

  • Very bad itching of the scalp
  • Small, red bumps on the scalp, neck, and shoulders (bumps may become crusty and ooze)
  • Tiny white specks (eggs, or nits) on the bottom of each hair that are hard to get off

 

Exams and Tests

 

Head lice can be hard to see. You need to look closely. Use disposable gloves and look at the person's head under a bright light. Full sun or the brightest lights in your home during daylight hours work well. A magnifying glass can help.

To look for head lice:

  • Part the hair all the way down to the scalp in very small sections.
  • Examine the scalp and hair for moving lice and eggs (nits).
  • Look at the whole head in the same way.
  • Look closely around the top of the neck and ears (the most common locations for eggs).

Both children and adults should be treated right away if any lice or eggs are found.

 

Treatment

 

Lotions and shampoos containing 1% permethrin (Nix) often work well. You can buy these medicines at the store without a prescription. If these products do not work, a health care provider can give you a prescription for stronger medicine. Always use the medicines exactly as directed. Using them too often or in the wrong way can cause side effects.

To use the medicine shampoo:

  • Rinse and dry the hair.
  • Apply the medicine to the hair and scalp.
  • Wait 10 minutes, then rinse it off.
  • Check for lice and nits again in 8 to 12 hours.
  • If you find active lice, talk to your health care provider before doing another treatment.

You also need to get rid of the lice eggs (nits) to keep lice from coming back.

To get rid of nits:

  • You can use products that make the nits easier to remove. Some dishwashing detergents can help dissolve the "glue" that makes the nits stick to the hair shaft.
  • Remove the eggs with a nit comb. Before doing this, rub olive oil in the hair or run the metal comb through beeswax. This helps make the nits easier to remove.
  • Metal combs with very fine teeth are stronger and work better than plastic nit combs. These metal combs are easier to find in pet stores or on the Internet.
  • Comb for nits again in 7 to 10 days.

When treating lice, wash all clothes and bed linens in hot water with detergent. This also helps prevent head lice from spreading to others during the short period when head lice can survive off the human body.

Ask your provider if people who share bedding or clothes with the person who has head lice need to be treated as well.

 

Outlook (Prognosis)

 

Most of the time, lice are killed with the proper treatment. However, lice can come back if you do not get rid of them at the source.

 

Possible Complications

 

Some people will develop a skin infection from scratching. Antihistamines can help ease itching.

 

When to Contact a Medical Professional

 

Call your provider if:

  • You still have symptoms after home treatment.
  • You develop areas of red, tender skin, which could signal an infection.

 

Prevention

 

Never share hair brushes, combs, hair pieces, hats, bedding, towels, or clothing with someone who has head lice.

If your child has lice, be sure to check policies at schools and daycare. Many places do not allow infected children to be at school until the lice have been completely treated.

Some schools may have policies to make sure the environment is clear of lice. Cleaning of carpets and other surfaces often helps prevent spread of all types of infections, including head lice.

 

 

References

Devore CD, Schutze GE; Council on School Health and Committee on Infectious Diseases. Head lice. Pediatrics . 2015;135(5):e1355-65. PMID: 25917986 www.ncbi.nlm.nih.gov/pubmed/25917986 .

Diaz JH. Lice (pediculosis). In: Bennett JE, Dolin R, eds. Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases . 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 294.

Elston DM. Arthropods and leeches. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 359

Habif TP. Infestations and bites. In: Habif TP, ed. Clinical Dermatology . 6th ed. Philadelphia, PA: Elsevier; 2016:chap 15.

Kliegman RM, Stanton BF, St Geme JW. Arthropods bites and infestations. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016:chap 668.

 
  • Getting rid of lice in the home

    Animation

  •  

    Getting rid of lice in the home - Animation

    Can you get rid of lice in the home without washing everything in sight? Watch this video to find out.

  • Head lice - illustration

    Head lice infect the scalp and hair and can be seen at the nape of the neck and over the ears. Head lice spread easily and quickly but do not carry disease as other lice do.

    Head lice

    illustration

  • Nit on human hair - illustration

    This photograph shows a "nit" or tiny white egg sack attached to the shaft of a human hair. (Image courtesy of D. Scott Smith, MD, MSc, DTM&H)

    Nit on human hair

    illustration

  • Head louse emerging from egg - illustration

    This is a photograph of a head louse emerging from an egg. Head lice have become an increasing problem in schools and day care centers. Some grade schools have started programs to examine children for head lice.

    Head louse emerging from egg

    illustration

  • Head louse, male - illustration

    Pediculus humanus var. capitis

    Head louse, male

    illustration

  • Head louse - female - illustration

    Pediculus humanus var. capitis

    Head louse - female

    illustration

  • Head louse infestation - scalp - illustration

    This is a close-up picture of lice egg sacks (nits) on the hair. They cling to individual hair shafts. (Image courtesy of the Centers for Disease Control and Prevention.)

    Head louse infestation - scalp

    illustration

  • Lice, head - nits in the hair with close-up - illustration

    This photograph shows the "nits" or tiny white egg sacks attached to the hairs. Schools often insist that these be entirely removed before a child returns to school.

    Lice, head - nits in the hair with close-up

    illustration

  • Getting rid of lice in the home

    Animation

  •  

    Getting rid of lice in the home - Animation

    Can you get rid of lice in the home without washing everything in sight? Watch this video to find out.

  • Head lice - illustration

    Head lice infect the scalp and hair and can be seen at the nape of the neck and over the ears. Head lice spread easily and quickly but do not carry disease as other lice do.

    Head lice

    illustration

  • Nit on human hair - illustration

    This photograph shows a "nit" or tiny white egg sack attached to the shaft of a human hair. (Image courtesy of D. Scott Smith, MD, MSc, DTM&H)

    Nit on human hair

    illustration

  • Head louse emerging from egg - illustration

    This is a photograph of a head louse emerging from an egg. Head lice have become an increasing problem in schools and day care centers. Some grade schools have started programs to examine children for head lice.

    Head louse emerging from egg

    illustration

  • Head louse, male - illustration

    Pediculus humanus var. capitis

    Head louse, male

    illustration

  • Head louse - female - illustration

    Pediculus humanus var. capitis

    Head louse - female

    illustration

  • Head louse infestation - scalp - illustration

    This is a close-up picture of lice egg sacks (nits) on the hair. They cling to individual hair shafts. (Image courtesy of the Centers for Disease Control and Prevention.)

    Head louse infestation - scalp

    illustration

  • Lice, head - nits in the hair with close-up - illustration

    This photograph shows the "nits" or tiny white egg sacks attached to the hairs. Schools often insist that these be entirely removed before a child returns to school.

    Lice, head - nits in the hair with close-up

    illustration

Self Care

 

    Tests for Head lice

     

       

      Review Date: 2/15/2016

      Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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