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Scabies

Definition

Scabies is an infestation of the skin. It is caused by a tiny mite.
Scabies
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Causes

An infestation results when the female mite burrows into the skin and lays its 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:
Scabies can also spread from person to person by sharing:
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.
Factors that increase your chance of scabies include:

Symptoms

Symptoms of scabies include:
In more severe cases, the infested area may:
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:

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, an oral medicine, called 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 your risk of getting scabies, avoid close physical contact with anyone who has either had scabies or has had an undiagnosed itchy rash. Do not share their:
To prevent the spread of scabies from one person to another:

RESOURCES

American Academy of Dermatology http://www.aad.org

Family Doctor—American Academy of Family Physicians http://familydoctor.org

CANADIAN RESOURCES

Canadian Dermatology Association http://www.dermatology.ca

Health Canada http://www.hc-sc.gc.ca

References

Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines, 2010. MMWR 2010;59(No. RR-12):1-110.

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 shampoo and lindane lotion. Center for Drug Evaluation and Research. Food and Drug Administration website. Available at: http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm110452.htm. Updated June 18, 2009. Accessed January 15, 2015.

Medication guide lindane lotion USP, 1%. Center for Drug Evaluation and Research. Food and Drug Administration website. Available at: http://www.fda.gov/downloads/Drugs/DrugSafety/UCM133687.pdf. Updated August 2007. Accessed January 15, 2015.

Medication guide lindane shampoo USP, 1%. Center for Drug Evaluation and Research. Food and Drug Administration website. Available at: http://www.fda.gov/downloads/Drugs/DrugSafety/UCM133688.pdf. Updated August 2007. Accessed January 15, 2015.

Mumcuoglu KY, Gilead L. Treatment of scabies infestations. Parasite. 2008;15(3): 248-251.

Revised lindane lotion label. Center for Drug Evaluation and Research. Food and Drug Administration website. Available at: http://www.accessdata.fda.gov/drugsatfda%5Fdocs/label/2003/006309lotionlbl.pdf. Accessed January 15, 2015.

Revised lindane shampoo label. Center for Drug Evaluation and Research. Food and Drug Administration website. Available at: http://www.accessdata.fda.gov/drugsatfda%5Fdocs/label/2003/006309shampoolbl.pdf. Accessed January 15, 2015.

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.

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