What Is the First Sign of Scabies?

A scabies infestation causes an intensely itchy rash.

Scabies is an intensely itchy skin condition caused by an infestation with the Sarcoptes scabiei hominis mite. These microscopic-sized mites burrow into the skin where they lay eggs. Scabies is very common, and it affects about 300 million people worldwide each year.

Scabies mites are highly contagious and spread from person to person by prolonged direct skin contact with an infested person. It appears in crowded places where people come into close contact with one another, such as nursing homes, prisons, homeless shelters, and child care centers.

Symptoms and signs of scabies include the following:

• Intense itching, especially at night
• Pimple-like itchy rash
  • Rash may affect most of the body or may be limited to sites such as the wrists, webbing between the fingers, elbows, armpits, nipples, waist, penis and scrotum, belt line, feet, and buttocks.
  • Rash may include blisters and scales
  • Scratching the rash may cause sores that can become infected.
• Tiny burrows seen on the skin that appear as tiny raised and crooked grayish-white or skin-colored lines on the skin
• In geriatric patients, scabies may appear as scratches on the back.
• In infants and small children, burrows may appear on the palms of the hands and soles of the feet.

The Sarcoptes scabiei hominis mite causes scabies, and it spreads by prolonged, person-to-person direct skin contact with an infested person. Contact usually must be prolonged; a quick handshake or hug generally does not spread scabies.

Scabies can spread easily to household members and sexual partners. Less commonly, scabies may spread indirectly by sharing the clothing, bedding, or towels of an infested person, particularly when the person has crusted scabies.

Doctors may make a diagnosis of scabies by noting the symptoms of itching and appearance of the characteristic burrows on the skin. Medical professionals usually confirm the diagnosis by identifying the scabies mite, mite eggs, or mite feces under a microscope.

Products called scabicides treat scabies mites. Some also kill the eggs. Scabicidal agents include the following:

• Permethrin (Nix Creme Rinse, Elimite)
• Ivermectin (Soolantra, Sklice, Stromectol)
• Lindane

To use a scabicide,

• apply the cream or lotion to all parts of the body from the neck down to the toes or as directed by a doctor;
• for infants and young children, the cream or lotion may also be applied to the head and neck;
• leave the medication on the body for the recommended time on the label or as prescribed and then rinse;
• wear clean clothes after treatment; and
• another treatment may be needed if the itching continues for more than 2 to 4 weeks after treatment, or if new rash or burrows appear.

If a secondary infection develops, doctors may also prescribe antibiotics.

Crusted scabies may require multiple scabicide treatments and sometimes several different medications used one after another. Scabies nodules may require steroid injections.

It may be necessary to consult with a dermatologist or an infectious disease specialist in severe cases.

In addition to treating the infested person, medical professionals will lilely also recommend treatment for all household members and sexual partners. All people who have had close, prolonged skin-to-skin contact with the infested person should be treated at the same time to avoid reinfestation.

Scabies mites do not survive more than 3 days away from human skin so clothing, bedding, and towels used by a person with scabies can be decontaminated by washing in hot water and drying using the hot cycle or by dry-cleaning.

Crusted scabies, however, is highly infectious so careful vacuuming of furniture and carpets in rooms used by people with crusted scabies is recommended.

Animals do not spread human scabies, so pets do not require treatment.

Scabies complications are uncommon and typically result from vigorous scratching of the itchy rash. This puts the patient at risk for secondary bacterial invasion, primarily by Streptococcus pyogenes and Staphylococcus aureus. Superinfection with S. pyogenes can cause cellulitis, acute poststreptococcal glomerulonephritis, chronic kidney failure, and even rheumatic fever.

It's possible to prevent scabies by avoiding prolonged direct skin contact with infested individuals. This means avoiding sexual contact with an affected person, as well.

All household members and sexual partners who have come into close, prolonged contact with a person who has scabies should be treated for scabies, even if they do not have symptoms or signs. Clothing, bedding, and towels should be machine washed in hot water and dried on the hot cycle or dry cleaned. Items such as furniture or carpets that cannot be laundered should be vacuumed.