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Scabies

What is scabies?

Scabies is a condition caused by Sarcoptes scabiei var. hominis, a microscopic mite that infests the top skin layer of humans. Scabies is not a result of poor personal hygiene, but is contracted through skin-to-skin contact with someone who is infested. People with scabies usually have only 10 or 12 mites on their body. Scabies should only be diagnosed by a health care provider; misdiagnosis by lay people is common. 

Signs and symptoms

  • Initial symptoms consist of small itchy bumps, blisters, or pus-filled bumps that break when scratched
  • Intense itching may occur, particularly at night or after a bath
  • Commonly affected areas include the hands and feet, especially the webbing between digits, inner wrists, and armpits
  • Other areas of the body may also be affected
  • Tiny, raised, crooked, grayish-white, or skin-colored burrows may be seen in the skin

Incubation period

The incubation period is the time from the mite’s penetration and entry into the top skin layer until the time the person with the infestation develops symptoms. People who have never had scabies before may not develop symptoms until two to six weeks after they are infested. For people who have had scabies before, the incubation period is much shorter and can be as little as one to four days.

Contagious period and spread

  • Scabies is transmitted by direct, prolonged, physical contact (skin-to-skin) with a person with infestation or through contact with infested clothing or bedding. A person with infestation can spread the scabies mite before they show signs and symptoms. Mites cannot reproduce or survive without a human host, so objects like toys and desks are not important in the spread of scabies. 
  • People with infestation can spread the mites until the mites and eggs are destroyed by treatment. 

Public health reporting requirements

  • Individual cases are not reportable. 
  • The facility director, school nurse, or child care health consultant should be consulted for specific concerns. Consultation with the state or local public health agency is available. 

Control of spread

  • Refer suspected people with an infestation to a health care provider for diagnosis and treatment.
  • Close contacts of a person with infestation should be monitored for symptoms, or may be treated prophylactically.
  • The type and duration of contact will determine whether prophylaxis is needed. Sexual contacts are at high risk for infestation.
  • Environmental control measures
    • Scabies mites cannot live for longer than four days away from humans, thus mites in the environment will die in a few days if there is no host to feed on. 
    • Clothing and bedding used by a person with scabies in the three days before treatment is started should be laundered using hot water and the high-heat setting on the dryer.
    • Items from a person with scabies that cannot be laundered can be placed in a sealed plastic bag for at least four days. 
    • Carpets and furniture can be vacuumed. Do not use pesticides.

Treatment

  • Treatments for scabies are only available with a prescription. Anyone who suspects they have scabies should consult their health care provider for a diagnosis and prescription.
  • Itching is due to a reaction to the mite, its eggs, and its feces in the skin. Itching may increase and even continue for several weeks following a successful treatment as the mites die.
  • Mites can be resistant to treatment. A health care provider should be consulted if symptoms persist for more than three weeks after treatment. 
  • Family members and very close contacts should be treated at the same time as a child/student, even if no signs or symptoms are present.

Exclusion

  • Exclude children/students with scabies from the end of the program or school day until after treatment has started. 
  • Until the end of the program or school day, avoid any activity involving prolonged skin contact.

Role of teachers, caregivers, and family

  • Scabies affects people from all socioeconomic levels without regard to sex, age, or personal hygiene. Perceptions of social stigma and physical discomfort caused by scabies can affect a child’s ability to learn and perform in the school environment. 
  • Use and encourage good hand-hygiene techniques.
  • Use standard precautions when cleaning or touching open sores or lesions.