Causes
Scabies is caused by a tiny mite. An infestation results when the female mite burrows into the skin and lays eggs. The scabies mite does not suck blood. It does not transmit any disease other than scabies between people.
Scabies is highly contagious. Most often, it is passed from person to person through:
- Close and generally prolonged physical contact
- Sexual contact
Scabies can also spread from person to person by sharing:
- Clothing
- Towels
- Bedding
Scabies can occasionally also be acquired from certain mammals. It is most common from dogs with sarcoptic mange. Scabies from dogs differs somewhat from human scabies. It rarely passes from person to person.
Risk Factors
Children younger than 15 years of age and adults older than 65 years are at greater risk for this condition.
Other factors that may increase the chances of scabies:
- Sexual contact with new or multiple partners
- Close, physical contact with a person who has scabies
- Living in close quarters with others such as in a nursing home or military barracks
- A weakened immune system
- Close contact with an animal with scabies
Symptoms
Symptoms of scabies include:
- Intense itching, which is usually worse at night
- Small red bumps, pimples, or lines on the skin
In more severe cases, the infested area may:
- Appear crusty
- Become infected and discharge pus
Scabies rarely affects the face or head. While any other body area, or even the whole body, may be involved, areas most often affected include:
- Hands, especially between the fingers
- Wrists and elbows
- Feet
- Genitals and pubic area (especially in men)
- Buttocks
- Around the nipples (especially in women)
- Waistline
- Belly button and lower abdomen
- Areas where clothing is tight
- Under rings, watches, or jewelry
Diagnosis
You will be asked about your about symptoms and medical history. A physical exam will be done. While scabies can often be diagnosed based on these steps, a skin sample may be taken. The sample is examined under a microscope to confirm the diagnosis.
Treatment
It is essential to remove scabies from the living environment to avoid re-infestation after treatment. All bedding and clothing must be thoroughly washed. Other members of the household or facility should be treated.
Permethrin Cream 5%
Scabies is usually treated by applying permethrin cream 5%. It is applied to the skin from the neck down. The cream is left on for 8-12 hours, usually overnight. Excessive use of this medication can be harmful, especially in infants. Carefully read and follow the directions. It is best not to repeat treatments unless told to do so by a doctor.
Itch Relief
It may take several weeks for itching to disappear following successful treatment. Itching can be temporarily relieved with:
- Antihistamine
- Corticosteroid cream
- Antihistamines and corticosteroids
Alternative Medications
Some severe cases may respond poorly to treatments. In this case, oral ivermectin is sometimes prescribed. It is given as a single dose that must be repeated after 1 week.
Alternative topical creams include crotamiton 10% and lindane 1%.
Lindane should only be used when other medications have not been effective. Lindane can be toxic. It should not be overused. Follow the directions as given.
Prevention
To reduce the chances of scabies, avoid close physical contact with anyone who has either had scabies or has had an undiagnosed itchy rash. Do not share their:
- Clothing
- Towels
- Bedding
To prevent the spread of scabies from one person to another:
- Consider getting treatment if you share living quarters with an infected person and/or have close physical contact, even if no symptoms are present.
- Wash or dry clean all clothing, bedding, and towels that may have become infested. Set washing or drying temperatures to 140ºF (60ºC) or higher. Mites may live for at least 2-5 days after they leave a human body. They are probably infectious during some or all of that time, especially in room temperatures of 68ºF (20ºC) and above. Some experts suggest that items that cannot easily be cleaned be placed in a plastic bag for at least 3 days.
- Try to avoid contact for several days with hard-to-clean or non-cleanable items, like upholstered furniture. Talk to your doctor about ways to deal with household items that cannot be cleaned.
RESOURCES
American Academy of Dermatology https://www.aad.org
Family Doctor—American Academy of Family Physicians https://www.familydoctor.org
CANADIAN RESOURCES
Canadian Dermatology Association https://www.dermatology.ca
Public Health Agency of Canada https://www.canada.ca
References
Sexually transmitted diseases treatment guidelines. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/std/tg2015/default.htm. Accessed January 29, 2021.
Currie BJ, McCarthy JS. Permethrin and ivermectin for scabies. New Engl J of Med. 2010:362(8):717-725.
Hu S, Bigby M. Treating scabies: results from an updated Cochrane review. Arch Dermatol. 2008:144(12):1638-1640.
Leone PA. Scabies and pediculosis pubis: an update of treatment regimens and general review. Clin Infect Dis. 2007;44 Suppl 3:S153-S159.
Lindane. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T233229/Lindane . Accessed January 29, 2021.
Mumcuoglu KY, Gilead L. Treatment of scabies infestations. Parasite. 2008;15(3): 248-251.
Scabies. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T115753/Scabies . Accessed January 29, 2021.
Strong M, Johnstone PW. Interventions for treating scabies. Cochrane Database Syst Rev. 2007;(3):CD000320.
Wolf R, Davidovici B. Treatment of scabies and pediculosis: facts and controversies. Clin Dermatol. 2010;28(5):511-518.
Revision Information
- Reviewer: EBSCO Medical Review Board David L. Horn, MD, FACP
- Review Date: 03/2020
- Update Date: 01/29/2021