Clinical Notes : Dermatology

196. Body Lice infestation and bites

What is a louse ?

 

A louse (plural lice) is a small insect that lives on human hair and clothing and can just be seen with the naked eye. Lice are well camouflaged and reflect the colour of the surroundings.

The medical term for an infection or infestation with lice is pediculosis. 

Lice are ectoparasites that live on the human body.

They are wingless and have six legs on which are attached strong claws that they use to grasp on tightly to hair shafts or clothing fibres.

With their piercing mouthparts they puncture the skin to feed on human blood.

They also inject a saliva which causes itching.

 

Adult lice can’t live longer than 24 hours or so on nonhuman surfaces like carpets, hardwood floors, clothing, furniture, sports helmets, headphones, or hair accessories.

​Nits can’t live without a human host. They need the warmth of the scalp for incubation before they hatch. They need the nourishment they get from human blood as soon as they’ve hatched.

There are three types of lice that infest humans.

  • Pediculus humanus var. capitis – head lice

  • Pediculus humanus var. corporis – body lice

  • Phthirus pubis – pubic lice

 

Head lice, the most common infestation in humans, are colloquially known as cooties and their eggs are called nits.

Pubic lice are smaller than the other two species, and have a short body resembling a crab — hence the common name for pubic lice, 'crabs'.

 

What are body lice ?

 

Lice are insects that infest humans, causing a condition called pediculosis.

The proper name for the body louse is Pediculus humanus var. corporis.

 
 

How do you get body lice ?

Infestation with body lice is uncommon in comparison to head lice.

Body lice tend to infest people in extreme states of poverty or personal neglect, particularly when unwashed and wearing the same clothing for weeks-on-end.

The risk of catching body lice is increased in close, crowded living situations, such as in refugee camps and crowded buses/trains.

Shared bedding and/or clothing or very close contact with a person infested with lice can be the cause of body lice spreading.

 

Body lice have been responsible for spreading diseases such as rickettsial typhus.

What do body lice look like and where do the live ?

 

The body louse is larger than the head louse and is between 2 and 4mm in size.

The body louse is flat and white to grey in colour.

 

Body lice do not live on the body, they only crawl onto the body when they need to feed.

They can survive for up to 10 days away from the human body without a blood meal.

When they are not feeding they live and lay their eggs on the fibres of clothing, mainly close to the seams.

A female body louse can lay 10–15 eggs per day on clothing and on average, 20 adult female lice are usually found on a person with an infestation.

 

How do you get rid of body lice ?

Treating the body infested with lice is not usually necessary as the lice live on the clothing.

 

If the infestation is widespread and covers much of the body, insecticides used in the treatment of head lice may also used in the treatment of body lice.

Environmental measures are the focus of treating body louse infestations.

 

Laundering of clothing and bed linens using hot washes is essential to killing body lice and their eggs on clothing.

  • Hot washing and hot tumble-drying is effective in killing lice and eggs.

  • Ironing with a hot iron is effective.

  • Dry cleaning is also effective.

  • Sometimes a topical insecticide spray can be applied to clothing, especially the seams.

 

Regular hot washing of clothes and bathing has led to a decrease in incidence of body lice but during wartime and in some undeveloped countries the condition can still occur.

 

Household contacts and close friends should also be educated about hygiene and how to launder clothing and linen to prevent the spread of body lice and reinfestation.

 
 
 

Pubic lice

DermNetNZ  (CCPL)

Access

Permethrin is available in Ireland as Lyclear Creme Rinse and Lyclear Dermal Cream

Ivermectin is available in Ireland as Soolantra

The following meds are not available in Ireland :

Malathion

Phenothrin

Spinosad

 

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