Scabies usually is spread by direct, prolonged, skin-to-skin contact with a person who has scabies. Contact generally must be prolonged; a quick handshake or hug usually will not spread scabies. Scabies is spread easily to household members. Scabies sometimes is spread indirectly by sharing articles such as clothing, towels, or bedding used by an infested person.
You can get scabies from another individual as long as the mite is present on the person infested. This includes the 30 days prior to the person even showing symptoms. It is for that reason that households usually should be treated at the same time in order to prevent a reoccurrence of infestation.
Scabies is an infestation of the skin by the human itch mite (Sarcoptes scabiei var. hominis). The microscopic scabies mite burrows into the upper layer of the skin where it lives and lays its eggs. The most common symptoms of scabies are intense itching and a pimple-like skin rash. The scabies mite usually is spread by direct, prolonged, skin-to-skin contact with a person who has scabies.
Scabies is found worldwide and affects people of all races and social classes. Scabies can spread rapidly under crowded conditions where close body and skin contact is frequent. Institutions such as nursing homes, extended-care facilities, and prisons are often sites of scabies outbreaks. Child care facilities also are a common site of scabies infestations.
The most common signs and symptoms of scabies are intense itching, especially at night, and a pimple-like itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria.
Tiny burrows sometimes are seen on the skin; these are caused by the female scabies mite tunneling just beneath the surface of the skin. These burrows appear as tiny raised and crooked grayish-white or skin-colored lines on the skin surface. Because mites are often few in number (only 10-15 mites per person), these burrows may be difficult to find. They are found most often in the webbing between the fingers, in the skin folds on the wrist, elbow, or knee, and on the penis, breast, or shoulder blades.
The head, face, neck, palms, and soles often are involved in infants and very young children.
On a person, scabies mites can live for as long as 1-2 months. Off a person, scabies mites usually do not survive more than 48-72 hours. Scabies mites will die if exposed to a temperature of 50°C (122°F) for 10 minutes.
Diagnosis of a scabies infestation usually is made based on the customary appearance and distribution of the rash and the presence of burrows. Whenever possible, the diagnosis of scabies should be confirmed by identifying the mite, mite eggs, or mite fecal matter. This can be done by a laboratory skin scraping to examine under a microscope for mites, eggs, or mite fecal matter. It is important to remember that a person can still be infested even if mites, eggs, or fecal matter cannot be found; typically fewer than 10-15 mites can be present on the entire body of an infested person who is otherwise healthy.
The mite cannot live off of a human for longer than 72 hours, and dies in the laundry. Therefore, you can prevent mite infestations by cleaning clothes or sealing items in a bag for longer than 72 hours. General hand hygiene can also help to reduce the transfer of mites. You can also prevent scabies by reducing prolonged close contact, refraining from sharing clothing and other personal items, and by examining your skin regularly for rashes.
Products to treat human scabies are available only with a doctor’s prescription; no "over-the-counter" (non-prescription) products have been tested and approved for humans.
Always follow carefully the instructions provided by the doctor and pharmacist, as well as those contained in the box or printed on the label. When treating adults and older children, scabicide cream or lotion is applied to all areas of the body from the neck down to the feet and toes; when treating infants and young children, the cream or lotion also is applied to the head and neck. The medication should be left on the body for the recommended time before it is washed off. Clean clothes should be worn after treatment.
In addition to the infested person, treatment also is recommended for household members, particularly those who have had prolonged skin-to-skin contact with the infested person. All persons should be treated at the same time in order to prevent reinfestation. Retreatment may be necessary if itching continues more than 2-4 weeks after treatment or if new burrows or rash continue to appear.