What is Scabies?
Scabies, officially known as Sarcoptic acariasis, is a contagious condition of the skin caused by a parasitic mite. This eight-legged, burrowing critter is called Sarcoptes scabiei, and is so tiny that it can barely be seen with the aid of a magnifying glass. Scabies is named after the Latin word of the same spelling that is translated “itch.” Very aptly named, as the characteristic symptom of a scabies attack is severe itching.
The mites that cause scabies are only about three-tenths of a millimeter long, and infestations in humans can involve anywhere from a handful of mites up to millions in extreme cases. The female mite burrows under the skin of her human host, laying down a line of eggs as she travels under the skin and creates a tunnel. As these eggs hatch, they rise to the surface of the skin, and repeat the breeding cycle either on the original host, or on a new one that they are introduced to. From egg to mature mite takes about 21 days.
The intense itching associated with scabies is due to several factors. It is thought that the itch is caused by allergic reactions primarily to the waste products excreted by the mites, and secondarily to the eggs and the mites themselves. This itching can be unbearable to many patients, and it seems to be worse at night while sleeping.
Household pets, such as dogs and cats, can be infected by mites and come down with scabies as well. The condition is called mange in dogs. However, each species, including humans, has a different type of mite that prefers them as their host. Thus, people can be infested by dog and cat mites, but these parasites cannot live long away from their host of choice, and cases such as these do not last long or become very severe. They usually appear as temporary, minor skin irritations at worst.
How Do You Get Scabies?
Scabies is most often found in parts of the world that are overcrowded, and where personal hygiene is poor. It is estimated that there are approximately 300 million new cases of scabies every year worldwide. Scabies is mostly transmitted from person to person via direct skin contact, like through sexual relations or by sleeping in close contact with an infected person. Close quarters in daycare, school, or nursing home settings are also common environments for the spread of scabies. However, sharing bedding, clothing, or personal items can potentially spread the mites as well, although it is more difficult for this to occur than through direct contact. The mites can only live for about three days away from the skin of a human host. Close contact is usually necessary to spread the mites, but scabies is not classified as a sexually transmitted disease (STD).
It typically takes about four to six weeks after a person is infested with the mites before any symptoms surface. During that period of time, an infected individual can potentially expose many other people to the scabies. Treatment is often recommended for the whole family and any sleeping partners of the family (even siblings who share bedrooms) when one person is discovered to be infected, due to the likelihood that they may have the mites, but have yet to exhibit symptoms.
What Are the Symptoms of Scabies?
Intense itching is definitely the most definitive sign of a scabies infestation. However, there are quite a few other skin disorders that produce itching as well, so you need to look for some other evidence to nail down a scabies diagnosis. The most common scabies symptoms include:
- Severe itching that is almost impossible to resist. It is usually worse at night or after a hot shower.
- “Tracks” that are left on the skin as the mite burrows to form a tunnel. They are often hard to find, and typically appear in folds of the skin, but may be found anywhere on the body. They are usually gray, and described as “pencil-like” lines that usually have a characteristic zigzag look. They are composed of tiny blisters or bumps on the skin. One of the reasons the tracks are hard to spot is because consistent scratching of them tends to obscure them from view.
- At the end of the burrow, a pearly dark bump may be seen on the skin. This is the actual female mite that is responsible for the burrowing.
- Scabies may appear anywhere on the body, but the most common locations are:
- Between the fingers
- Sides of the fingers
- In the armpits
- Breasts of men and women
- Nipples of women
- Top of the wrists
- Insides of the wrists
- Genitals of men
- Around the waist
- Lower part of the buttocks
- Shoulder blades
- In babies: On the face, soles of the feet, and palms of the hands.
The vast majority of scabies cases involve very few mites. The average is 11-14 mites per infestation in otherwise healthy people. The mites will often surface, especially at night. This is why the itching often gets worse at night. Sometimes, scratching can actually help the situation. When they are on the surface, scratching can actually kill them. However, it is recommended to scratch with a washcloth rather than with the bare hand, to avoid possible secondary infections.
Rare but extreme cases may involve infestations of hundreds of thousands to millions of mites. This usually only occurs on folks who do not scratch, and who have been exposed and infested with the mites for many years. Examples of cases such as this are mentally ill people in institutions, disabled or elderly folks who are physically unable to scratch, and patients who have diseases that deaden their ability to feel any sensations on the skin (like leprosy). Major infestations such as these are called crusted scabies or Norwegian scabies. The skin of their entire body may be thickened, scaly, and crusted.
Are There Any Possible Complications From Scabies?
If you have any kind of an immune system problem, such as HIV or diabetes, or are being treated with chemotherapy or any other medications that can affect your immune system, any infection can be dangerous, and scabies is no exception. However, if you are otherwise healthy, there is typically only one complication you need to be concerned about. Vigorous scratching can irritate the skin and put you at risk of a secondary bacterial infection. An example of this is a condition known as impetigo, which is often caused by staphylococci or streptococci bacteria.
How is Scabies Diagnosed?
In order to eliminate other skin disorders, there are ways to positively determine if a person has scabies. Your health care practitioner should do a thorough visual examination of the suspected areas. Sometimes the burrows or tracks may be difficult to find. If they cannot be located in the itchy areas, the entire body should be examined. Sometimes they are easier to see in areas that have not yet begun to show other symptoms. Another way to find the burrows is to topically apply ink or a special tetracycline solution to affected areas. After being wiped off with an alcohol pad, the burrows can be more easily seen, especially under a special light. The “S” shaped or zigzag pattern can then be more easily identified.
Samples of suspected areas can also be scraped off and treated on a slide with certain chemicals that will expose the mites, eggs, or fecal excretions under a microscope if they are present.
How Can Scabies Be Treated?
Most of the drugs that are prescribed for the treatment of scabies are heavy-duty chemicals with numerous dangerous side effects. We’re talking topical pesticides here folks. I would be very careful about exposing myself or my children to any of these “medicines.” Several of them have been banned in countries such as the United Kingdom and Australia, but are still available here in the good ol’ USA. One such drug is called Lindane (hexachlorocyclohexane), which is a known neurotoxin that has been proven to be harmful to both unborn and born infants and children.
I would also stay away from drugs containing steroids or corticosteroids. These chemicals can weaken your immune system and actually worsen your scabies and open the door for many other kinds of infections.
One drug that is safe and effective is one that was historically the first line of defense against scabies for many years, but is currently out of vogue due to all the new (and dangerous) drugs available. A topical 10% sulfur solution is very effective against scabies if used for seven days. It is even safe for babies and pregnant women. It is also very inexpensive as compared to the cost of prescription drugs. Keep in mind that the itching will often continue even during treatment, so don’t think it isn’t working. Sometimes you may experience itchiness for several weeks after treatment.
Some practical steps to stop the spread of the mites and prevent reinfestation include:
- Wash everything: All bedding, clothing, linens, and personal items should be thoroughly washed with soap and hot water, and put in the dryer on high heat. If an item needs to be dry-cleaned, do it. If you don’t get all the mites, the chance of a recurring problem is very high.
- Starve them out: If there are any items you can’t wash or dry clean, put them in a plastic bag and get them out of the house in a shed or the garage for a week, just to be sure. They will die from lack of food in 3 or 4 days.
Self-care tips to help with the interminable itching include:
- A lukewarm bath with colloidal oatmeal in the water can do wonders for your itchy skin.
- A compress of diluted vinegar can also be very helpful. Mix ¼ cup of white vinegar with 2 quarts of lukewarm water. Soak the compress in this and apply for 10 minutes, twice daily. Many folks find this to be very soothing.
- If the itching is unbearable, try over-the-counter antihistamines. They can temporarily help to relieve the itch.