Links to other pages within Patient UK which are related to this topic:
Experience | Leaflets | Patient+ | Guidelines | Weblinks | News | Products | Other
Print options:   Other options:   Bookmark and Share

This is a PatientPlus article. PatientPlus articles are written for doctors and so the language can be technical. However, some people find that they add depth to the articles found in the other sections of this website which are written for non-medical people.

Lice are blood-sucking insects and specific parasites of human beings. Lice are 1-3 mm long and have three pairs of legs that end in powerful claws. Pubic lice are slightly smaller than head lice and body lice. The female lives for 1-3 months but dies when separated from the host. The female louse lays up to 300 eggs, called nits, during her lifetime. These nits are less than 1 mm in diameter and, when viable are opalescent. The nits hatch 6-10 days after laying, giving rise to nymphs that become adults in 10 days. 3 species of lice have adapted to live on humans:

  • Head louse (Pediculus humanus capitis) - see separate article on Head Lice
  • Body louse (Pediculus humanus)
  • Crab (or pubic) louse (Pthirus pubis) - see below
Body lice

Epidemiology

  • There are hundreds of millions of cases of pediculosis worldwide.
  • Pediculosis and scabies may coexist in the same individual.
  • Body lice are associated with poor socioeconomic conditions, with infestation occurring mainly when clothes are not changed or washed regularly. Therefore homeless populations are predominantly affected.1
  • Pediculosis is usually caused by contact with an infested person.

Presentation

  • Patients usually present after discovering lice or nits.
  • Many lice infestations are asymptomatic.
  • Pruritus is accompanied by excoriations that can become infected secondarily and papules linked to bite reactions.
  • Diagnosis is based on seeing eggs (nits), nymphs or mature lice. Observing lice is difficult. Nymphs and mature lice, despite being unable to hop or jump, can move rapidly through dry hair. The use of a magnifying glass assists with diagnosis.
  • Mature lice are 3-4 mm long. Nits are much smaller (about 1 mm). The pubic louse is about the same length as the head or body louse but has a wider body.
  • Body lice can be found in any area of the body, although they tend to avoid the scalp, except at the margins. Nits are laid in the host's clothing and are not usually not found on the hair as with head lice and pubic lice. Body lice and eggs are found in clothing seams.1
  • Chronic infestation often leads to post-inflammatory pigmentation.1

Investigations

  • Unlike dandruff and hair root sheath casts, nits are cemented to the hair and are difficult to remove.
  • Nits are fluorescent under a Woods light.

Management

  • Bed linens and clothes must be systematically decontaminated.
  • Thorough washing of the body with soap followed by application of pyrethroids (permethrin, phenothrin) or malathion for 8-24 hours.
  • Outbreaks require delousing of people with 1% permethrin dusting powder, basic sanitation, and hygiene to assure changes of clean clothing, washing of the body, and sometimes shaving.
  • Antibiotics are needed to treat louse-borne infectious diseases.
  • Treating clothing with permethrin may prevent infestation.

Complications

Prognosis

  • Treatments are very effective in killing nymphs and mature lice but less effective in killing eggs.
  • Appropriate therapy produces a cure in more than 90% of cases.

Prevention

  • To prevent reinfestation, treat contacts of the patient at the same time as the patient.
  • Washing combs and brushes reduces reinfestation.


Pubic lice
  • The pubic louse (Pthirus pubis) is 'crab' shaped, grey-brown in colour, and about 2 mm in length.2 The female lays eggs (smaller than a pinhead) on the hair shaft, near to the body. The eggs hatch after about 7 days. The empty eggshells (nits) are tightly attached to the hair and cannot be brushed off.

Epidemiology

  • Common among young adults.2
  • Pubic lice are transmitted by close body contact, which can be from sexual contact or from close family contact (e.g. from an infested beard or chest).
  • Pubic lice in children may be an indication of sexual abuse.

Presentation

  • The diagnosis is based on finding adult lice and/or eggs.
  • Itching is worse at night and may not develop for several weeks.
  • Pubic lice may be found in any coarse hair, such as moustaches, beards, axillary hair and around the margins of the scalp, as well as pubic hair. In prepubertal children, eyebrows and eyelashes are common sites of infestation.
  • Blue macules may be visible at feeding sites.
  • Minute dark-brown specks of louse excreta are sometimes seen on the skin and underwear.

Differential diagnosis

  • Seborrhoeic scales, small crusts of scratched dermatitis, and hair casts may look like nits but the can all be brushed off whereas nits are very adherent to hairs.
  • Clothing lice and head lice are slightly larger than pubic lice.

Management

  • Sexual contacts from the previous 3 months and close family contacts should be examined, and treated if infested. It is recommended that those affected and sexually active should have a full screen of sexually transmitted infections.
  • Patients should also be screened for associated sexually transmitted disease and treated as necessary.
  • Symptoms respond to a topical parasiticidal preparation. In order to kill those lice emerging from eggs that survived the first application, a second applications of insecticide is used 7 days later.
  • All hairy surfaces of the body should be treated, including the scalp, neck, ears, and face (paying particular attention to the eyebrows and any beard).
  • A different insecticide should be used if a course of treatment fails.
  • Alcoholic lotions are not recommended (cause irritation of excoriated skin and the genitalia).
  • Recommended treatment regimes include:3
    • Malathion 0.5%: apply to dry hair and wash out after at least 2 hrs but preferably, 12 hours, i.e. overnight. Aqueous malathion lotion is effective for crab lice of the eye lashes (unlicensed use).
    • Permethrin 1% cream rinse: apply to damp hair and wash out after 10 minutes.
    • Phenothrin 0.2%: apply to dry hair and wash out 2 hours later.
    • Eyelashes should be carefully examined for lice, but not treated unless necessary (with 1% permethrin or vaseline).
    • Removal of lice with forceps or application of vaseline (particularly for eyelash infestation in children) are alternative treatments.
  • Treatment of itch: antihistamines are of little help in treating pruritus but an oral sedating antihistamine at night may help with sleeping and so reduce scratching.
  • If treatment is ineffective, a different class of insecticide should be used for the second course of treatment. This reduces repeated exposure to the same insecticide and so reduces the development of resistance to the medication.1

Prevention

  • Shaving the infested areas does not provide protection from re-infestation because pubic lice need only a minimal length of hair on which to lay eggs.

Document references
  1. Chosidow O; Scabies and pediculosis. Lancet. 2000 Mar 4;355(9206):819-26. [abstract]
  2. Pubic lice, Clinical Knowledge Summaries (2007)
  3. Management of pediculosis pubis, British Association of Sexual Health & HIV (2008)
Acknowledgements EMIS is grateful to Dr Colin Tidy for writing this article. The final copy has passed scrutiny by the independent Mentor GP reviewing team. ©EMIS 2008.
DocID: 2991
Document Version: 22
DocRef: bgp24953
Last Updated: 21 Aug 2008
Review Date: 21 Aug 2010

The authors and editors of this article are employed to create accurate and up to date content reflecting reliable research evidence, guidance and best clinical practice. They are free from any commercial conflicts of interest. Find out more about updating.

Patient UK Hearing Impairment Survey

Patient UK are grateful to the 550 people who took part in this survey.
To see the results click here.
If you'd like to leave your feedback, please go to our interactive forum.

Links to other pages within Patient UK which are related to this topic:
Experience | Leaflets | Patient+ | Guidelines | Weblinks | News | Products | Other
Print options:   Other options:   Bookmark and Share
Want to search some more? Use the Google Search box below to search our site.

Related pages in Patient UK

Your Experience (^ top of page)

 Please add your experience about this condition / medicine
 View Patient Experience for 'Pubic Lice' (2 there)
 Head Lice - Detection
 Head Lice - Full Overview
 Head Lice - Medicated Treatment
 Pubic Lice

 Head Lice
 Insect Bites and Infestations
 Scabies

 Guidelines on Pubic Lice

 Lice
 Pubic Lice

Recent related news items

 Bed bug infestations 'increasing'
 Bedbug cases on the rise in NY

All news by related topic

 Body Lice news
 Pediculosis news

Online Pharmacy

 Derbac M Liquid 200ml
 Derbac M Liquid 50ml
 Quellada-M Liquid

Medical equipment


Visit the Patient UK Medical Equipment shop

Books


Visit the Patient UK shop

Other - Useful resources (^ top of page)

Pictures, diagrams, photos, images, etc.
Evidence based medicine
Online textbooks and journals
UK Guidelines
Online Videos
Medline
Other good health sites

Want to search some more? Use the Google Search box below to search our site.

Advertisements











Disclaimer: Patient UK has no control over the content of any external links above. Inclusion does not imply endorsement by Patient UK.

Want to advertise on this site? Find out how >>

Clicking here will take you to the foot of this page where you'll find a list of Information Leaflets which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Support Groups which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Medicines & Drugs which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of diagrams which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of PatientPlus (detailed reference) articles which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of UK Guidelines which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of other selected websites which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Poems and Stories which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Operations and Procedures which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Online Videos which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find links through to our interactive forum.
Here you can follow a link to view existing patient experiences on this subject, or to add your own
Clicking here will take you to the foot of this page where you'll find links to news stories on this subject in our Online Newspaper
Clicking here will take you to the foot of this page where you'll find links to related products
Clicking here will take you to the foot of this page where you'll find links to other useful sources of information
Click here to open a printer-friendly version of this document, in a new window, together with the print dialogue box
Click here to open this document in PDF format
This will offer you the usual PDF options i.e. document navigation, search, zoom and formatted print
Note: this is the best way to print the document
Click here to listen to the MP3 audio recording of this document
Click here to download the audio recording of this document as a podcast, for listening to at your leisure
Click here to open our Dictionaries and Glossaries page
Click here to see related products in our Online Pharmacy
Note: this will open in a new window
Click here to add this page to a social bookmarking site of your choice
Click here if you want to find out more about social bookmarking. This link will take you to the Wikipedia explanation
Note: this will open in a new window
Clicking here will take you to the foot of this page where you'll find a list of Information Leaflets which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Support Groups which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Medicines & Drugs which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of diagrams which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of PatientPlus (detailed reference) articles which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of UK Guidelines which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of other selected websites which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Poems and Stories which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Operations and Procedures which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Online Videos which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find links through to our interactive forum.
Here you can follow a link to view existing patient experiences on this subject, or to add your own
Clicking here will take you to the foot of this page where you'll find links to news stories on this subject in our Online Newspaper
Clicking here will take you to the foot of this page where you'll find links to related products
Clicking here will take you to the foot of this page where you'll find links to other useful sources of information
Click here to open a printer-friendly version of this document, in a new window, together with the print dialogue box
Click here to open this document in PDF format
This will offer you the usual PDF options i.e. document navigation, search, zoom and formatted print
Note: this is the best way to print the document
Click here to listen to the MP3 audio recording of this document
Click here to download the audio recording of this document as a podcast, for listening to at your leisure
Click here to open our Dictionaries and Glossaries page
Click here to see related products in our Online Pharmacy
Note: this will open in a new window
Click here to add this page to a social bookmarking site of your choice
Click here if you want to find out more about social bookmarking. This link will take you to the Wikipedia explanation
Note: this will open in a new window
Click here to return to the home page
Click here to read our 'About Us' page
Go to the Emis Access website, where you can book an appointment with your GP, order a repeat prescription or view you medical record online.
Note: this will open in a new window
View and/or join in discussion about health, lifestyle and disease in our interactive forum.
Note: this will open in a new window
Visit our pharmacy product price comparison website
Go to our online newspaper for current medical news and commentary.
Note: this will open in a new window
Adverts on this site do not influence the medical content. Click to read more.
Adverts on this site do not influence the medical content. Click to read more.