Lice: Most Common Questions

What are lice?

  • Lice generally refer specifically to the head louse, but there are also body louse, and pubic or crab louse. Going further, louse/lice will refer to the head louse/lice.
  • Unlike body lice and public lice, head lice are not a vector for disease transmission.
  • Lice are parasitic insects that life on the human scalp and feed on blood.
  • Lice are wingless and cannot fly, but have claws that are well adapted to clutching human hair.
  • Lice spend their entire life cycle which lasts about a month on human hair.
  • Lice lay eggs called nits on human hair

Who can get lice?

  • Anyone can get lice
  • Personal hygiene has no influence on the likelihood of catching lice.
  • Lice are more commonly found in school-aged children from 4-14.
  • Girls are 2 to 4 times more likely to catch lice, very likely due to their longer hair on average and the sharing of combs and brushes that come into contact with hair.

How is lice transmitted?

  • Lice are transmitted via direct hair to hair contact or via shared items that come into contact with hair such as combs, brushes, hats, coats, and headphones.
  • Lice can be transmitted by shared bedding or use of bed sheets.
  • Transmission via furniture is far less likely as lice depend on the human host for warmth as well as nutrition and cannot survive long without it.
  • Lice are not transmitted from or to pets. These insects are species specific, meaning that human head lice can only feed off human blood, and dog lice can only feed off dog blood.
  • Lice is transmitted more easily in public settings where the chance of physical hair contact is high such as elementary schools, daycares, and children's parties

What are the symptoms of a lice infestation?

  • Itching of the scalp and back of the neck (caused by immune reaction to lice saliva)
  • Itch may not be present for 2 to 6 weeks as the itch is not caused by lice directly but by the immune system responding to the lice's saliva and waste, and it takes time for the immune system to react.
  • The presence of nits (eggs) in the scalp. They are shaped like a flask and can be seen attached to the side of the hair shaft. They are most commonly seen around the neck area, scalp, and behind the ears.
  • The presence of adult lice. They can move relatively quickly on the hair and due to their small size, they can be difficult to identify.

How is lice treated?

  • Lice, while annoying, are not dangerous. With proper treatment, they can be completely removed within several weeks.
  • Anti-lice treatments are usually pesticides, but there are non-pesticide treatments that are also effective such as Resultz.
  • Anti-lice treatments should be applied as instructed, ensuring that sufficient quantities are used, and that the hard to reach areas such as the area behind the ears are reached.
  • Many lice treatments require a re-treatment at about 7 days after the initial treatment to ensure that all the lice are eradicated.
  • Lice combs are specialized fine combs that can isolate strands of hair and help remove lice and nits. Use metal combs as they are sturdier. We recommend brushing the hair with a solution made of 50% vinegar and 50% water to remove the nits easier. Pull the comb outward starting at the scalp and repeat, removing the nits in the process and repeat on a daily process.

How do I prevent lice from spreading in the household?

  • Stop direct head to head contact with the infested member. This is by far the most common method of transmission, and why it spreads among children through play.
  • Avoid sharing clothes that come into contact with the infested child's head. Common items that can spread lice include hats, coats, bed linen, towels, and pillow cases. These should be washed in hot water (at least 50 degrees Celsius) and dried in a hot drier.
  • Carpets are usually not a mode of transmission as lice cannot live long outside of the hair for long. However, it doesn't hurt to vacuum the carpets to reduce the off-chance transmission.

Are there any side-effects to lice treatments?

Most lice treatments are insecticides such as Pyrethrin or Permethrin which act on the lice's nerve system, rendering them unable to breathe. Outside of rare allergies (to Chrysanthemum flowers usually), these treatments do not have any adverse effects on people. Those who are pregnant should consult their doctors to ensure that there aren't any potentially adverse reactions to lice medication.