Scabies

Written by Shannon Johnson | Published on August 7, 2012
Medically Reviewed by Brenda B. Spriggs, MD, MPH, FACP

What Is Scabies?

Scabies is a skin infestation caused by a tiny microscopic bug known as the human itch mite. This mite is usually passed from skin to skin. It can also be transmitted through infested clothing or bedding.

Scabies mites can live on your skin for up to two months. They mate on your skin’s surface, and then the females burrow into your skin and lay eggs. After the eggs hatch, new mites migrate to your skin’s surface. Infestation of other humans can occur when the impregnated female mite is transferred by touch or simply by brushing against the skin of an infected individual. Mites are cream colored with bristles and spines.

Scabies is condition that affects people worldwide, irrespective of race or social standing. A person with a scabies infestation usually will have between 10 and 15 mites. Scabies is easily spread. It just requires direct, extended skin-to-skin contact with someone who is infected. The World Health Organization estimates that there are more than 300 million cases of scabies worldwide each year (WHO).

Scabies is easily transmitted to household members and sexual partners. Scabies also gets transmitted when people live in close contact with one another and in crowded conditions such as schools, nursing homes, and prisons. If one person is infected with scabies, doctors will usually recommend treatment for the entire group of people in frequent contact with that person.

According to the Centers for Disease Control and Prevention, there are two types of scabies—scabies and crusted (or “Norwegian”) scabies (CDC).

Symptoms: Recognizing a Scabies Infestation

After a person is exposed to scabies, it can take four to six weeks before the symptoms start appearing. This is because the symptoms are mostly caused by an allergic reaction to the mites, their saliva, eggs, or waste products. This reaction takes time to appear, if you’ve never had scabies. If you have had scabies, the symptoms could appear within one to four days after being exposed.

Mites are most active at night and the most intense itching occurs at night. Telltale symptoms of scabies include intense nighttime itching and a rash. Continuous scratching of the infected area can create sores that become infected.

In babies and young toddlers the commonly infected sites are:

  • head
  • face
  • neck
  • palms
  • soles

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

  • wrist
  • elbow
  • armpit
  • between fingers
  • nipple
  • penis
  • waist
  • beltline
  • buttocks

The rash itself can be pimply, made up of tiny blisters, and/or it can be scaly. In addition, the burrows of the mite can appear on the skin. They look like tiny, raised, dirty white, or flesh-toned lines.

Transmission: How Is Scabies Spread?

There are a number of ways that scabies can be spread. For example:

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

Indirect transmission of scabies is less common than direct skin-to-skin transmission. Scabies mites can only live for 48 to 72 hours when not in contact with skin. Indirect transmission is more likely when a person has crusted scabies, and the shard fabric has been in direct contact with skin.

What Is Crusted (Norwegian) Scabies?

Norwegian or crusted scabies 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 does not always create itchy skin or the rash. It can be spread by:

  • direct skin-to-skin contact
  • clothing
  • bedding
  • furniture

Crusted scabies is usually found in people with weakened immune systems, such as the elderly and infirm. The mites are able to overpower the immune system and multiply at a quicker rate than they would on a healthy individual.

Symptoms of crusted scabies include widespread crusts on the skin that are:

  • thick
  • crumble easily when touched
  • gray in color

How Scabies Is Diagnosed?

The rash and burrows are the main signs that doctors use to determine if you have a scabies infestation.

Doctors will often try to confirm a visual diagnosis by removing a mite from a burrow with a needle or skin scraping. The sample is examined under a microscope to confirm the presence of mites and/or eggs.

Treating Scabies

After a doctor has diagnosed a scabies infestation, the next step is to get immediate treatment. Most treatments will be applied directly to the skin. You will probably be told to treat all skin from the neck down.

The medicine is applied at night, when the mites are most active. It is washed off the following morning. You should make sure to strictly follow your doctors’ instructions regarding treatment.

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

  • 5 percent permethian cream (most common treatment)
  • 25 percent benzyl benzoate lotion
  • 10 percent sulfur ointment
  • 10 percent crotamiton cream
  • 1 percent lindane lotion

Doctors often prescribe other medications to help with the annoying symptoms of scabies. These include antihistamines and/or prazmoxine lotion to help control the itch and assist you with getting rest. You also may be given antibiotics to kill any infections that occur from scratching your skin. Steroid creams can also help with the swelling and itch.

Treatment for severe or widespread scabies is more aggressive. Ivermectin is a pill given to those with crusted scabies, people whose scabies covers most of the body, or people whose scabies do not respond to the topical treatment. This medication has the potential to cause serious side effects that will be discussed with you by your doctor.

During your first week of treatment, it may seem as if the symptoms are getting worse. However, after the first week, you will have less itching. You should be completely healed by week four of your treatment. Skin that has not healed within a month may still be infected with mites.

Eradicating Scabies From Your Body and Home

Mites can live for 48 to 72 hours after falling off your body. It is important to wash all clothing, bedding, towels, and pillows in hot water that reaches 122 degrees F. They should then be dried on the hottest setting for at least 10 to 30 minutes.

Anything that cannot be washed should be thoroughly vacuumed. When finished, throw out the vacuum bag and clean the vacuum well with bleach and hot water. Bleach and hot water can also be used to clean surfaces.

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