Dermatology Associates of Plymouth Meeting, P.C.

Patient Education

WHAT ARE SCABIES?

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Did I get scabies from my pet?

Animals do not spread human scabies. Pets can become infested with a different kind of scabies mite that does not survive or reproduce on humans but causes “mange” in animals. If an animal with “mange” has close contact with a person, the animal mite can get under the person’s skin and cause temporary itching and skin irritation. However, the animal mite cannot reproduce on a person and will die on its own in a couple of days. Although the person does not need to be treated, the animal should be treated because its mites can continue to burrow into the person’s skin and cause symptoms until the animal has been treated successfully.

Can scabies be spread by swimming in a public pool?

Scabies is spread by prolonged skin-to-skin contact with a person who has scabies. Scabies sometimes also can be spread by contact with items such as clothing, bedding, or towels that have been used by a person with scabies, but such spread is very uncommon unless the infested person has crusted (Norwegian) scabies.

Scabies is very unlikely to be spread by water in a swimming pool. Except for a person with crusted (Norwegian) scabies, only about 10-15 scabies mites are present on an infested person; it is extremely unlikely that any would emerge from under wet skin.

Although uncommon, scabies can be spread by sharing a towel or item of clothing that has been used by a person with scabies.

How can I remove scabies mites from my house or carpet?

Scabies mites do not survive more than 2-3 days away from human skin. Items such as bedding, clothing, and towels used by a person with scabies can be decontaminated by machine-washing in hot water and drying using the hot cycle or by dry-cleaning. Items that cannot be washed or dry-cleaned can be decontaminated by removing from any body contact for at least 72 hours.
Because persons with crusted (Norwegian) are considered very infectious, careful vacuuming of furniture and carpets in rooms used by these persons is recommended.

Fumigation of living areas is unnecessary.

How can I remove scabies mites from my clothes?

My spouse and I were diagnosed with scabies. After several treatments, he/she still has symptoms while I am cured. Why?

The rash and itching of scabies can persist for several weeks to a month after treatment, even if the treatment was successful and all the mites and eggs have been killed. Your health care provider may prescribe additional medication to relieve itching if it is severe. Symptoms that persist for longer than 2 weeks after treatment can be due to a number of reasons, including:

Incorrect diagnosis of scabies. Many drug reactions can mimic the symptoms of scabies and cause a skin rash and itching; the diagnosis of scabies should be confirmed by a skin scraping that includes observing the mite, eggs, or mite feces (scybala) under a microscope. If you are sleeping in the same bed with your spouse and have not become reinfested, and you have not retreated yourself for at least 30 days, then it is unlikely that your spouse has scabies.
Reinfestation with scabies from a family member or other infested person if all patients and their contacts are not treated at the same time; infested persons and their contacts must be treated at the same time to prevent reinfestation.
Treatment failure caused by resistance to medication, by faulty application of topical scabicides, or by failure to do a second application when necessary; no new burrows should appear 24-48 hours after effective treatment.
Treatment failure of crusted (Norwegian) scabies because of poor penetration of scabicide into thick scaly skin containing large numbers of scabies mites; repeated treatment with a combination of both topical and oral medication may be necessary to treat crusted scabies successfully.
Reinfestation from items (fomites) such as clothing, bedding, or towels that were not appropriately washed or dry-cleaned (this is mainly of concern for items used by persons with crusted scabies); potentially contaminated items (fomites) should be machine washed in hot water and dried using the hot temperature cycle, dry-cleaned, or removed from skin contact for at least 72 hours.
An allergic skin rash (dermatitis); or
Exposure to household mites that cause symptoms to persist because of cross-reactivity between mite antigens.

If itching continues more than 2-4 weeks or if new burrows or rash continue to appear, seek the advice of a physician; retreatment with the same or a different scabicide may be necessary.

If I come in contact with a person who has scabies, should I treat myself?

No. If a person thinks they might have scabies, he/she should contact their doctor. The doctor can examine the person, confirm the diagnosis of scabies, and prescribe an appropriate treatment. Products used to treat scabies in humans are available only with a doctor’s prescription.

Sleeping with or having sex with any scabies infested person presents a high risk for transmission. The longer a person has skin-to-skin exposure, the greater is the likelihood for transmission to occur. Although briefly shaking hands with a person who has non-crusted scabies could be considered as presenting a relatively low risk, holding the hand of a person with scabies for 5-10 minutes could be considered to present a relatively high risk of transmission. However, transmission can occur even after brief skin-to-skin contact, such as a handshake, with a person who has crusted (Norwegian) scabies. In general, a person who has skin-to-skin contact with a person who has crusted (Norwegian) scabies would be considered a good candidate for treatment.

To determine when prophylactic treatment should be given to reduce the risk of transmission, early consultation should be sought with a health care provider who understands:

the type of scabies (i.e. non-crusted vs crusted) to which a person has been exposed;
the degree and duration of skin exposure that a person has had to the infested patient;
whether the exposure occurred before or after the patient was treated for scabies; and,
whether the exposed person works in an environment where he/she would be likely to expose other people during the asymptomatic incubation period. For example, a nurse or caretaker who works in a nursing home or hospital often would be treated prophylactically to reduce the risk of further scabies transmission in the facility.