What Is Scabies?
Scabies is not a skin infection, but a skin infestation caused by the itch mite Sarcoptes scabiei and, in humans, Sarcoptes scabiei var. hominis. These microscopic scabies mites burrow into the epidermis, where they live and lay their eggs. These mites can live on your skin for months without treatment, causing intense itching and a pimple-like rash. In most cases, the scabies mite spreads through direct and prolonged skin-to-skin contact with a patient infected with scabies, though it may be transmitted in many other ways. This skin condition is found worldwide and may affect anyone. Scabies can spread quickly because it is so highly contagious, particularly in crowded conditions where close contact with others is frequent and common. The most common sites of scabies infestations include extended-care facilities, child-care facilities, classrooms, daycares, dorms, student residences, gyms, sports locker rooms, prisons, and nursing homes. However, a scabies outbreak may occur anywhere.
Following initial exposure to the mites that cause this condition, it may take anywhere from 2–6 weeks for scabies signs and symptoms to appear. Patients who have previously had scabies, however, scabies symptoms typically develop more quickly, usually developing within 1–4 days of exposure. Intense itching that becomes more severe at night is the most common symptom of scabies. Another hallmark symptom of this condition is the scabies rash, which causes lumps and bumps to form under the skin, often positioned in a linear formation. The bumps may appear similar to hives, pimples, knots beneath the skin's surface. Some individuals with scabies form patches on their skin that look like eczema or dermatitis.
Sarcoptic mange in humans may produce sores due to constant scratching of the affected skin. Should sores develop, so too may an infection. Non-stop scratching may even lead to sepsis. With a severe form of scabies (crusted scabies), thick crusts can form on the skin and, as an increasing number of mites burrow into the skin, the rash and itch escalate in severity.
In most adults with scabies, the mites rarely burrow into the skin located above the neck. Scabies may occur anywhere on the skin, but the mites typically prefer to burrow in certain places on the body, including the following.
- Between The Fingers
- Around The Nails
- Inner Elbows
- Inside Of The Wrists
- Soles Of The Feet
- Around The Beltline
- Genital Areas
Scabies in infants and toddlers, the elderly, and the immunocompromised may occur on the head, face, neck, hands, and soles of the feet, among other areas. In addition, children may develop widespread scabies, where the rash covers most skin on the body. In these cases, a child's scalp, palms, and soles of the feet may simultaneously be infested with mites.
Types Of Scabies
Sarcoptes scabiei (Sarcoptes scabiei var. hominis) is the only type of mite that causes a scabies infestation. But these mites can cause multiple scabies types, including typical scabies, nodular scabies, and Norwegian scabies (crusted scabies).
A typical scabies infestation occurs when an individual has more than 10 live adult mites on or burrowed in their skin. This results in an itchy rash on the skin, most commonly on the hands and wrists.
Nodular scabies is a less common form of scabies characterized by firm, itchy, red nodules that form on or near the genitalia. These nodules may persist for months, even after specific treatment for scabies.
Norwegian scabies, also commonly referred to as crusted scabies, is a more severe and contagious form of traditional scabies. This type of scabies is characterized by vesicles and thick crusts which form over the skin before falling off. These crusts typically contain a large number of scabies mites and eggs. Norwegian scabies is more prevalent in institutionalized, immunocompromised, or debilitated patients. The lesions produced by crusted scabies are extensive and may spread all over the body, though the elbows, knees, psalm, scalp, and soles of the feet are the most common sites. A significant danger of this scabies type is that the resulting lesions often predispose the individual to developing a number of secondary infections. Persons with crusted scales may not experience the usual signs and symptoms of scabies, such as the scabies rash or itching sensations.
What Causes Scabies?
The eight-legged, microscopic scabies mite causes scabies in humans. This type of mite is microscopic and female mites easily burrow under the skin's uppermost layer, creating a tunnel in which it deposits eggs. When the eggs hatch, the mite larvae ascend to the surface of the skin, where they mature and spread to other parts of the body and onto other individuals. The itching produced by scabies results from the body's allergic reaction to the mites as well as the mites' eggs and waste. Close physical contact with a patient with scabies and the sharing of mite-infested clothing or bedding can spread the infestation.
Like humans, animals can likewise become affected by scabies mites, though the mites that affect animals are a different species from those affecting humans. Following direct contact with scabies-affected animals, humans may develop a temporary skin reaction with the animal scabies mite. Humans, however, cannot typically develop full-scale scabies from this source, however, as they would after coming into contact with human scabies mites. Scabies mites can live on a human body for up to 2 months, though off of a body, the mites usually die within 3–4 days.
What Does Scabies Look Like?
The most common signs of scabies are a papular scabies skin rash and intense itching, especially at night. The rash may include vesicles, or tiny blisters, that may become infected, as well as scales or patches. In some cases, tiny burrows can be seen on skin affected by scabies. These burows occur when female scabies mites tunnel just under the skin's surface. Burrows look like tiny, raised lesions with wavy margins that are gray, white, or skin-colored and form lines on the skin's surface. Unfortunately, in most scabies cases, the mites exist in few numbers, making these burrows difficult to identify.
Scabies treatment requires the elimination of the infestation using medications. Several scabies treatment creams and topical medications are available with a prescription from your dermatologist. Medications commonly prescribed for treating scabies are called scabicides as they kill scabies mites, while some scabicides also kill mite eggs. Unfortunately, these medications are available only with a prescription from a medical provider; no scabies treatment over the counter products have been tested and approved for treating human scabies.
Always follow the medication instructions given by your healthcare professional. For most individuals with scabies, the topical medication must be applied to all areas of the body, from the neck down to the toes. Following application, the medication should remain on the body for a minimum of 8–10 hours. Some treatment protocols may require a secondary application. If additional or new scabies symptoms appear, the treatment may require additional applications.
Because scabies spreads so easily and so rapidly, your dermatologist may recommend scabies rash treatment for all household members and close contacts, even in cases where no signs of scabies infestation are present. Although the medication prescribed to patients with scabies are formulated to kill scabies mites properly, the itching may not stop entirely for several weeks following treatment. Contact our office for more information about scabies treatments.
Scabies Home Treatment
Following treatment from your dermatologist for scabies, the sensations of itching may persist for some time. However, there are certain steps you can take to find relief from the itching, such as soaking your skin in cool water or an oatmeal bath or applying a cool, wet washcloth to the affected areas of the skin. You may also apply over-the-counter soothing calamine lotion or, at your doctor's suggestion, use over-the-counter antihistamines to relieve your scabies symptoms.
How Is Scabies Diagnosed?
Patients who have signs and symptoms that may indicate scabies should schedule an appointment with their physician. Several different skin conditions, such as dermatitis, associated with itching and the appearance of small skin bumps can resemble those from scabies infestations. During your appointment with our Boardman dermatologists, they will determine the exact cause of your symptoms to ensure you receive the required treatment. To diagnose scabies, your doctor will likely examine your skin and look for any signs indicating mites, such as burrows in the skin. If a mite burrow is detected, then your doctor may take a sample from that area of the skin to examine under a microscope. A microscopic examination of the skin scraping can help your doctor identify the presence of mites and their eggs.
Is Scabies Contagious?
Yes! Scabies is highly contagious and may be transmitted through close body contact, skin-on-skin contact, or sexual contact with a person who is infected with scabies. Scabies transmission may likewise occur following exposure to infested furniture, clothing, or linens. In most cases, scabies is contracted following prolonged exposure to an individual or item containing an infestation of scabies mites. This means that you are unlikely to become infected following a handshake or another form of quick contact with a scabies-infected individual. The close contact required to transmit scabies usually occurs within a household or another populated environment with close quarters. Individuals with weakened immune systems are particularly susceptible to contracting the more severe form of scabies, crusted scabies.
Effectively preventing scabies requires individuals to avoid all direct skin-to-skin contact with individuals known to have a scabies infestation. To be safe, stay away from unwashed clothing, bedding, fabrics, furniture, and other porous surfaces that were used by a person affected by scabies. Individuals with scabies and all household members and other potentially exposed individuals should receive treatment for scabies at the same time as the affected individual to prevent repeated exposure and reinfestation. Treatment should be sought promptly to prevent outbreaks of scabies. Outbreaks in institutional settings are particularly difficult to control and require a quick, sustained response.
Bedding, clothing, and other fabrics worn, used, or came into contact with individuals affected by scabies three or more days before treatment should be machine washed and dried using the "hot" cycles or should be professionally cleaned. Items that cannot be professionally cleaned or de-infested using hot water and hot dryer cycles should be stored in airtight plastic bags for a week or so.