How to eliminate head lice, scabies

Originally published in The Ottawa Citizen September 7, 2004

Original Title: The heebee jeebee itch

With the beginning of the school year, cold viruses, potential allergens and other infections are ready to greet our children at the door.Although we handle these situations well, the anxiety meter reaches a crescendo when we face those nefarious villains: scabies and head lice (Pediculosis).

Mention that your child has head lice and watch your friends and family members slowly back away from you, start scratching their heads or bodies and run for the nearest door.

What can parents and schools do to prevent and treat these infestations? Where do they come from and how do infestations occur?

Let us enter heebie-jeebie territory.

Head lice (Pediculus humanus capitis) are one of three types of lice that live only on humans. The other two are pubic lice (Phthirus pubis or crabs) and body lice (Pediculus humanus corpus). Contrary to popular belief, these insects do not fly, jump or hop from person-to-person, nor are they related to poor hygiene and low socioeconomic status.

Head-to-head contact is the primary mode of transmission, although sharing hats, combs and brushes can do so as well. Three- to 11-year-old children are most susceptible, especially girls because of their social behaviour.

The infestation can start two or more weeks prior to the development of the allergic reaction and itch (due to the louse’s saliva). Children will frequently scratch their heads once the bugs have set up shop.

Detecting lice can prove difficult because they move rapidly. Indeed, many will see the lice eggs or nits — tiny oval-shaped blobs that stick out at an angle from the hair shaft. Nits can be confused with normal skin flakes or dandruff. Dandruff is brushed off the hair shaft whereas nits are glued in place.

Finding nits does not mean there is an active infestation. If microscopic examination of the nit shows it contains an embryo or you find at least one louse, then there is an active colony. All family members must be examined for lice under this circumstance.

Eradication of head lice includes a combination of mechanical removal of nits with a nit comb or brush, substances to asphyxiate them, certain antibiotics and/or an insecticide. The insecticides are toxic to the louse’s nervous system.

Solvents such as formic acid and white vinegar will dissolve the cement that holds the eggs on the hair shaft, enabling easier removal of the nits. Although it may create a bit of a mess, applying olive oil and wearing a shower cap for six hours per day for four consecutive days may kill the lice and nits. Using petrolatum (Vaseline) on eyelashes produces good results.

The treatment of choice is usually an insecticide such as permethrin (Nix or Rid shampoo). It is safe and effective, it can be used even by those who are pregnant. Suspect insecticide resistance if lice are found alive 24 to 48 hours after treatment. Your doctor will recommend another agent.

Given that lice survive for only a day if separated from the human host, a simple wash of recently worn clothes is all that is required. Vacuum the furniture, toys and other household objects. A complete scrub-down is unnecessary.

The scabies mite (Sarcoptes scabiei) shares some of the head louse’s characteristics: it is a human parasite and is transmitted by direct contact. However, it can survive up to four days away from its human host on clothing, bedding and upholstered furniture. Contact with any of these infested objects can result in the bug’s transmission.

It will burrow into the underarms, elbow creases, waist, groin, buttocks and feet to lay its eggs. These areas become intensely itchy from the louse’s excrement and a bumpy red rash can develop. Skin damage (excoriations) occurs from the intense scratching. Infants may demonstrate larger sores or bumps on their skin and have head and neck involvement.

Adults and children older than five years of age can use a five-per-cent solution of permethrin. After a bath or shower, the cream is applied from the neck down to cover the entire body surface. It is washed off after eight to 14 hours. One application has a cure rate of about 90 per cent. Although generally safe for use by pregnant women, breastfeeding should be delayed or halted until all residual cream is washed off the skin.

Treatment failures should be assessed by your doctor.

Itching and discomfort can continue for up to four weeks after treatment. Leftover pieces of the mites will remain buried under the skin until the skin regenerates and sloughs the debris away. Antihistamines can help treat the itch.

All clothes, linens, towels, and upholstered furniture used in the previous four days must be decontaminated or the cycle of infestation may recur.

More information can be found at .

© Dr. Barry Dworkin 2004

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