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Why do people get scabies?

Scabies is a common skin condition caused by microscopic mites called Sarcoptes scabiei. These mites burrow into the top layer of human skin and lay eggs, causing an extremely itchy rash to develop on the skin.

What is scabies?

Scabies is an infestation of the skin by the human itch mite Sarcoptes scabiei. The microscopic scabies mites burrow into the upper layer of the skin and lay eggs. The body reacts to the mites with an intense itchy rash.

The scabies mites are very small, about the size of a pinhead, and can only be seen under a microscope. They spread easily through skin-to-skin contact and by sharing towels, bedding or clothing with someone who has scabies.

What causes scabies?

Scabies is caused by an infestation with the Sarcoptes scabiei mite. This tiny mite burrows into the top layer of human skin and lays eggs. The eggs hatch into larvae in 3-4 days, and the larvae move onto the skin surface. Once mature, the mites burrow back into the skin and the cycle repeats.

The presence of the mites and their waste products under the skin trigger severe itching and a pimply red rash. The rash typically appears a few weeks after initial infestation as a reaction to the eggs, mite secretions and feces.

How do you get scabies?

Scabies is contagious and spreads quickly in crowded conditions where there is frequent skin-to-skin contact between people. You can get scabies from:

  • Touching the skin of a person with scabies
  • Sexual contact with an infected person
  • Sharing towels, bedding or clothing with someone who has scabies
  • Prolonged skin-to-skin contact, like holding hands
  • Contact with items like furniture or clothing that have scabies mites on them

Scabies mites can only survive for 24-36 hours off a human host. However, brief contact with an infested person or item can allow the mites to crawl onto your skin and cause an infestation.

Who is at risk of getting scabies?

Anyone can get scabies, but certain populations are more at risk:

  • People in crowded living conditions: Prisons, nursing homes, extended care facilities, group homes, dormitories
  • Sexual partners of infected persons
  • Children in childcare settings and schools
  • Healthcare workers in direct contact with infected patients
  • People with weakened immune systems like the elderly, HIV/AIDS patients, cancer patients on chemotherapy
  • Impoverished communities with lack of access to healthcare and overcrowding
  • Homeless populations

Younger children and the elderly are especially vulnerable to complications from scabies infestations.

Signs and symptoms of scabies

The most common signs and symptoms of scabies include:

  • Intense itching, especially at night. Itching can occur all over the body or just in certain areas.
  • Rash on the skin, typically appears as small red bumps or blisters, and is often located between the fingers, on wrists and elbows, around the waist, in armpits, on the buttocks, genitals and nipples of women.
  • Soreness and skin irritation from constant scratching.
  • Crusty sores may form when blisters pop and ooze.
  • Burrows visible as tiny raised greyish-white or skin-colored lines on the skin surface.
  • Small clusters of bites, called nodules, in creases of skin.

In babies and young children, the rash may appear on the head, neck, palms and soles.

How is scabies diagnosed?

Doctors can often diagnose scabies based on the appearance and distribution of the characteristic rash. However, confirmatory tests may be done, including:

  • Microscopic examination – Scrapping some skin flakes and examining them under a microscope can reveal the presence of mites, eggs, or mite fecal matter.
  • Skin biopsy – Removing a small piece of skin for analysis can definitively diagnose scabies mites if present.

Doctors will also ask about potential exposure to scabies and symptoms in close contacts like family members.

Risk factors for developing scabies

Certain factors increase a person’s risk of getting scabies. These include:

Risk Factor Explanation
Crowded living conditions Scabies spreads quickly between people in close physical contact. Prisons, nursing homes, shelters, etc. are high risk.
Young children Children are prone to infection in daycares, schools and households.
Sexual contact Scabies easily spreads through skin-to-skin sexual contact with an infected partner.
Weakened immunity People with weakened immune systems are more susceptible to complications.
Healthcare workers Frequent contact with infected patients puts them at higher risk.
Impoverished communities Overcrowding and lack of access to healthcare contributes to spread.
Homelessness Difficulty maintaining hygiene and overcrowded shelters increase risk.

Complications of scabies

While scabies itself is rarely dangerous, scratching the rash can lead to complications like:

  • Bacterial skin infection – Breaks in the skin from scratching allow bacteria to enter and cause infections.
  • Abscesses or boils may form from deep bacterial infections of hair follicles.
  • Cellulitis, a potentially serious bacterial infection of the deeper layers of skin.
  • Permanent skin discoloration from injury caused by scratching.
  • Skin thickening and scarring from chronic scratching.

People with weakened immune systems are vulnerable to widespread crusted scabies, where mites and thick crusty sores cover large areas of the body. This is more difficult to treat and can increase mortality.

How to prevent getting scabies

You can reduce your risk of getting scabies through these preventive measures:

  • Avoid skin-to-skin contact with someone who has scabies.
  • Avoid sharing clothes, bedding, towels with infected people.
  • Wash clothes, towels and bedsheets used by infected people in hot water and dry in high heat dryer.
  • Disinfect furniture, mattresses and other potentially contaminated surfaces.
  • Practice good hygiene with frequent bathing and handwashing.
  • Avoid sexual contact with infected partners until fully treated.
  • Carefully follow treatment regimen to eliminate mites.
  • Be cautious when in contact with high-risk populations like homeless shelters, prisons, nursing homes, etc.

Treatment for scabies

Scabies is treated with medications that kill scabies mites and their eggs. Treatment options include:

  • Permethrin cream – Applied from the neck down and washed off after 8-14 hours. Often requires a repeat application 1 week later.
  • Ivermectin tablets – Taken orally, then repeat dose after 1-2 weeks. Especially useful for crusted scabies.
  • Other topical creams like lindane, crotamiton, benzyl benzoate may also be prescribed.
  • Oral antihistamines like Benadryl can help manage itching.
  • Antibiotics if secondary skin infection develops.
  • All close contacts should also be treated at the same time to prevent reinfestation.

It may take several weeks for symptoms to fully resolve, even after successful mite eradication. Supportive treatment for itching and sore skin may be needed during this time.


Scabies is an intensely itchy skin condition caused when the Sarcoptes scabiei mite burrows into and lays eggs in human skin. It spreads quickly via skin contact in crowded conditions. Proper diagnosis, treatment with medications that kill mites, and disinfection of contaminated items is key to eliminating scabies outbreaks. Preventive measures like avoiding skin contact with infected individuals, maintaining good hygiene, and promptly treating cases can also reduce spread.