Scabies

What is scabies?

Scabies is a skin infestation caused by a mite known as the Sarcoptes scabiei. Untreated, these microscopic mites can live on your skin for months. They reproduce on the surface of your skin and then burrow into it and lay eggs. This causes an itchy, red rash to form on the skin.

There are approximately 130 million cases of scabies in the world at any given time. It’s a highly contagious condition that can easily be passed from one person to another through direct skin contact. It may also be transmitted through infested clothing or bedding.

Although scabies can be bothersome, the infestation can usually be treated effectively. Treatment often consists of medications that kill scabies mites and their eggs. Since scabies is so contagious, doctors will usually recommend treatment for an entire group of people who are in frequent contact with a person who has scabies.

SYMPTOMS

What are the symptoms of scabies?

After the initial exposure to scabies, it can take up to six weeks for symptoms to appear. The symptoms usually develop more quickly in people who’ve had scabies before.

The hallmark symptoms of scabies include a rash and intense itching that gets worse at night. Continuous scratching of the infected area can create sores that become infected. If this occurs, additional treatment with antibiotics for the skin infection may be recommended.

Common sites for scabies in older children and adults include the:

• wrist
• elbow
• armpit
• nipple
• penis
• waist
• buttocks
• area between the fingers

Scabies in babies and toddlers, and sometimes the very elderly or immunocompromised, can include the:

• head
• face
• neck
• hands
• soles of the feet

The rash itself can consist of tiny bites, hives, bumps under the skin, or pimple-like bumps. The burrow tracks of the mite can sometimes be seen on the skin. They may appear as tiny raised or discolored lines.

Norwegian scabies

Some people with scabies may develop another form of scabies known as Norwegian scabies, or crusted scabies. This is a more severe and extremely contagious type of scabies. People with crusted scabies develop thick crusts of skin that contain thousands of mites and eggs.

Crusted scabies can also appear:

• thick
• gray
• easy to crumble when touched

Crusted scabies usually develops in people with weakened immune systems. This includes people with HIV or AIDS, people who use steroids or certain medications (such as some for rheumatoid arthritis), or people who are undergoing chemotherapy. The scabies mites can overpower the immune system more easily and multiply at a quicker rate. Crusted scabies spreads in the same way as normal scabies.

TRANSMISSION

Is scabies contagious?

Scabies is contagious. It can be spread in the following ways:

• prolonged skin-to-skin contact, such as holding hands
• intimate personal contact, such as having sexual intercourse
• sharing clothing, bedding, or towels that have been used by someone with a scabies infection

Since scabies is mostly transmitted through direct physical contact, the infestation can easily be passed on to family members, friends, and sexual partners. The infestation may also spread quickly in:

• schools
• nursing homes
• rehab facilities
• sports locker rooms
• prisons

DIAGNOSIS

How is scabies diagnosed?

Your doctor will likely be able to diagnose scabies simply by performing a physical exam and inspecting the affected area of skin. In some cases, your doctor may want to confirm the diagnosis by removing a mite from the skin with a needle. If a mite can’t easily be found, your doctor will scrape off a small section of skin to obtain a tissue sample. This sample will then be examined under a microscope to confirm the presence of scabies mites or their eggs.

TREATMENT

How is scabies treated?

Treatment for scabies usually involves getting rid of the infestation with prescription ointments, creams, and lotions that can be applied directly to the skin. Oral medications are also available.

Your doctor will probably instruct you to apply the medicine at night when the mites are most active. You may need to treat all of your skin from the neck down. The medicine can be washed off the following morning. Make sure you follow your doctor’s instructions very carefully. You may need to repeat the topical treatment in 7 days.

According to the American Academy of Dermatologists (AAD), some common medicines used to treat scabies include:

• 5 percent permethrin cream
• 25 percent benzyl benzoate lotion
• 10 percent sulfur ointment
• 10 percent crotamiton cream
• 1 percent lindane lotion

Your doctor may also prescribe additional medications to help relieve some of the bothersome symptoms associated with scabies. These medications include:

• antihistamines, such as Benadryl (diphenhydramine) or pramoxine lotion to help control the itching
• antibiotics to kill any infections that develop as a result of constantly scratching your skin
• steroid creams to relieve swelling and itching

More aggressive treatment may be needed for severe or widespread scabies. An oral tablet called ivermectin (Stromectol) can be given to people who:

• don’t see an improvement in symptoms after initial treatment
• have crusted scabies
• have scabies that covers most of the body

During the first week of treatment, it may seem as if the symptoms are getting worse. However, after the first week, you’ll notice less itching, and you should be completely healed by the fourth week of treatment. Skin that hasn’t healed within a month may still be infested with scabies mites. It’s important to remember that “post-scabies itch” can last up to one month.

Contact your doctor right away if you find that symptoms persist after four weeks of treatment.

CONTROL AND PREVENTION

How can I get rid of scabies?

The best way to prevent getting scabies is to avoid direct skin-to-skin contact with a person known to have scabies. It’s also best to avoid unwashed clothing or bedding that has been used by a person infested with scabies.

Scabies mites can live for 48 to 72 hours after falling off your body, so you need to take certain precautions to prevent reinfestation. Make sure to wash all of the following in hot water that reaches 122°F (50°C):

• clothing
• bedding
• towels
• pillows

These items should then be dried in the dryer on very high heat for at least 10 to 30 minutes.

Anything that can’t be washed should be thoroughly vacuumed. When you’re finished vacuuming, throw out the vacuum bag and thoroughly clean the vacuum with bleach and hot water. Bleach and hot water can also be used to clean other surfaces that may contain scabies mites.