Causes and Risk Factors of Scabies

The parasitic mite that causes scabiesSarcoptes scabieiis found all over the world and in a variety of settings. It is passed from person to person through skin-to-skin contact, which is often sexual contact, but certainly not always. 

Less often, a person can get scabies from contact with an object housing the mite, like bedding or clothing. The mite's life cycle depends on humans, and it cannot survive for longer than a few days outside a human host. While anyone can get scabies, certain individuals, such as those who live in crowded areas, have a greater risk.

scabies causes
Illustration by Joshua Seong. © Verywell, 2018.  

Common Causes

There is only one cause of scabies, and that is mite infestation. The adult female is the culprit. That said, it's skin-to-skin contact with someone who has the mite that typically results in scabies transmission. That can happen in a couple of different ways.

The Mite

The female mite burrows deep in the skin of an infected human host, laying eggs that hatch as larvae. Multiple larvae mature, causing symptoms of itching and rash as the infected human mounts an immune reaction. This exacerbates (worsens) the symptoms and inflammation.

The adult form of the larvae is able to mate as it lives and feeds on the human host's body. A pregnant female mite may travel through close human contact to another person, where she can then start the whole infectious process all over again. 

Close Contact

Close and prolonged skin contact with someone who has scabies is most often to blame. Usually, close family members and people who live together easily transmit the infection to one another. In adults, scabies is often (though not exclusively) transmitted by sexual partners.

Scabies is especially known to spread in crowded conditions. Outbreaks may occur in daycare settings, nursing homes, military quarters, prisons, and in shelters, for example.

In these situations, reinfection often occurs as infected individuals can pass the mite back to those who already had and were treated for scabies. Reinfection can also occur due to contaminated blankets and other items. 

Contact through professional massage can even spread the infection. Casual contact, such as a handshake, is not usually the source of scabies infection.

Contaminated Items

Households and residential facilities themselves can be infested with scabies. The mite can live on furniture, bedding, towels, and clothing for several days, causing transmission of the infection. However, this happens only when someone has a very severe infection.

Myths: Busted

Some incorrectly associate scabies with a lack of hygiene. Cleanliness does not prevent scabies. This is because the parasitic mite lives in deep layers of the skin and, therefore, cannot be washed off.

Likewise, having scabies does not mean that a person is "dirty." Instead, it means that a person has simply been in close contact with someone—or something—that has the infection.

It's also important to know that having been treated for scabies once doesn't mean you can't get it again.

Health Risk Factors

While getting scabies and developing the usual form of the infection can happen to anyone, Norwegian (crusted) scabies is more likely to occur in people whose immune systems are not optimal due to factors such as human immunodeficiency virus (HIV) infection, leukemia (blood cancer), chemotherapy treatment, treatment with other immunosuppressive medications, or severe nutritional deficiency. This is a more aggressive form of the infection.

Most scabies cases involve a total of 12–20 mites in the body. The Norwegian scabies may involve more than 1,000 mites.

Lifestyle Risk Factors

These choices or circumstances can increase the odds that you will be exposed to scabies or that it will be transmitted.


Caregivers who come into close contact with people, such as in a hospital setting, may acquire the infection, even if good hygiene is practiced. Wearing gloves or other protective coverings may decrease the chances of catching the infection in these settings.


If you live or spend a lot of time in cramped quarters, such as hospitals, nursing facilities, or military quarters, or have been exposed to contaminated bedding or clothes for a prolonged period of, you may contract scabies. 

A Word About Pets

While pets can transmit parasitic and bacterial infections to humans, the mite that causes scabies in humans is not typically transmitted to humans through contact with animals (or vice versa). There have been only a few case reports of transmission of scabies from animals to humans, and since these are so few, it is not believed that animals truly pose a risk. 

Frequently Asked Questions

  • Can I get scabies while working in my garden?

    No. Scabies are transmitted only via prolonged, direct contact with the skin of a person who has them. If you develop a rash that resembles scabies after gardening, doing yard work, hiking, or spending time in any sort of vegetation, it's possible you've been bitten by chiggers instead.

  • Do I have to get rid of my mattress if I have scabies?

    No, but it's a good idea to clean your mattress. Strip off all bedding and vacuum both sides of the mattress thoroughly, using the crevice attachment to get between seams and folds. Read the manufacturer's instructions for more specific guidance.

  • How do I get scabies out of my home?

    The mites that cause scabies can't live for more than two or three days without feeding on human skin, so if an infestation occurs in your household you don't need to worry about it recurring.

    Wash any items used by the infected person (towels, bedding, clothing, and so forth) in hot water and dry them on high heat. Dry clean what can't be safely laundered. If the household member had crusted scabies, it's a good idea to also thoroughly vacuum furniture and rugs.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Mccarthy JS, Kemp DJ, Walton SF, Currie BJ. Scabies: more than just an irritation. Postgrad Med J. 2004;80(945):382-7. doi:10.1136/pgmj.2003.014563

  2. Currier RW, Walton SF, Currie BJ. Scabies in animals and humans: history, evolutionary perspectives, and modern clinical management. Ann N Y Acad Sci. 2011;1230:E50-60. doi:10.1111/j.1749-6632.2011.06364.x

  3. Makigami K, Ohtaki N, Ishii N, Tamashiro T, Yoshida S, Yasumura S. Risk factors for recurrence of scabies: a retrospective study of scabies patients in a long-term care hospital. J Dermatol. 2011;38(9):874-9. doi:10.1111/j.1346-8138.2011.01199.x

  4. Crusted scabies. Genetic and Rare Diseases Information Center.

  5. Leistner R, Buchwald D, Beyer M, Philipp S. Scabies outbreak among healthcare workers in a German acute care hospital. J Infect Prev. 2017;18(4):189-192. doi:10.1177/1757177417690920

  6. Centers for Disease Control and Prevention. Scabies frequently asked questions (FAQs).

  7. Merck Manual Professional Version. Mite bites.

  8. Consumer Reports. How to clean a mattress (and why).

Additional Reading

By Megan Coffee, MD
Megan Coffee, MD, PhD, is a clinician specializing in infectious disease research and an attending clinical assistant professor of medicine.