Scabies and lice — How nice!

Just the words scabies and lice can start to make you itch, but with a little knowledge on your side these common creepy crawlies can be treated and prevented.

Scabies

Anyone can get scabies — an infestation of the skin caused by a mite. The female mite burrows into the top layer of the skin. This forms a slightly raised tunnel where the mite lays eggs and leaves waste. The mite is passed from person to person by skin contact or by sharing bedding, clothing, or other linens with a person who has scabies.

The most common symptom is an itchy rash. The rash usually itches most at night. It can appear anywhere on the body, but is usually on the hands, wrists, elbows, breasts, armpits, waistline, and groin. Persons who have never had scabies before usually notice symptoms about four to six weeks after contact with someone with scabies. Persons who have had scabies before may notice their symptoms sooner, often within a few days to one week. Elderly persons, persons in institutions, and persons whose immune system is weak may not feel itchy. 

It is possible to spread scabies from the moment of first contact until after all treatment is completed. Persons with symptoms should be checked and treated by their doctor as quickly as possible. Scabies is diagnosed by a doctor or nurse looking at the rash and/or by taking a scraping from the skin. If you are diagnosed with scabies, a medicated cream will be prescribed by your doctor. It is put on the skin, left on for several hours, and then washed off. You must put on clean clothes and use freshly laundered bed and bath linens. An oral medication may also be prescribed. Household members and other persons with skin-to-skin contact should be preventively treated.

Clothing, bedding, and bath linens used within the four days before the start of medication should be washed in a washer using hot water and dried using the hot dryer cycle. Clothing and other items that cannot be laundered should be stored in a closed plastic bag for one week. 

Head lice

Here are some facts about lice:

  • They do not transmit communicable diseases.
  • They do not jump or fly; they can only crawl.
  • The prevalence of head lice infestation is no different in individuals with long hair than in those with short hair. 
  • Head lice seldom occur on eyebrows or eyelashes. 
  • They infest persons from all socioeconomic levels, without regard for age, race, sex or standards of personal hygiene. 
  • Animals are not a source of human lice.
  • Children diagnosed with live head lice do not need to be sent home early from school; they can go home at the end of the day, be treated, and return to class after appropriate treatment has begun.
  • They are not usually spread by contact with clothing (such as hats, scarves, coats) or other personal items (such as combs, brushes, or towels). 

The diagnosis of a head lice infestation is best made by finding a live nymph or adult louse on the scalp or hair of a person. Because nymphs and adult lice are very small, move quickly, and avoid light, they can be difficult to find. Use of a magnifying lens and a fine-toothed comb may be helpful to find live lice. 

If crawling lice are not seen, finding eggs (also called nits) firmly attached within a 1/4 inch of base of the hair shafts strongly suggests, but does not confirm, that a person is infested and should be treated. Eggs (also called nits) that are attached more than 1/4 inch from the base of the hair shaft are almost always dead or already hatched. Eggs are often confused with other things found in the hair such as dandruff, hair spray droplets, and dirt particles. If no live nymphs or adult lice are seen, and the only eggs found are more than 1/4 inch from the scalp, the infestation is probably old and no longer active and does not need to be treated. If you are not sure if a person has head lice, the diagnosis should be made by their healthcare provider, local health department, or other person trained to identify live head lice.


Additional resources
The Centers for Disease Control and Prevention—Lice: Frequently asked questions
The Centers for Disease Control and Prevention—Scabies