How is scabies transmitted?

Sexual Transmission
Scabies are passed on through close physical contact. Transmission is more likely when partners spend the night together than during a brief sexual encounter.

Nonsexual Transmission
Sexual contact is not necessary to spread scabies. Prolonged contact between household members may allow transmission to occur. Transmission is also possible through prolonged contact with infested linens, furniture, or clothing. It is unlikely that scabies would be transmitted during casual contact (e.g. shaking hands or hugging) or contact with inanimate objects, such as a toilet seat.

The type of scabies that infest humans is specific to human beings and are different than the type that infest dogs and other animals (more commonly known as mange).

What are the symptoms?

• Persistent itching that usually becomes worse at night.
• Presence of the mite burrow(s), often in a zigzag or “S” pattern.
• Presence of lesions, such as brown nodules, rashes, or pimple-like irritations.

Common sites of infestation are: webs and sides of fingers and toes, pubic and groin area, armpits, bends of elbows and knees, wrists, navel, breasts, lower portion of buttocks, penis and scrotum, and waist and abdomen. Rarely, they are found on the palms of the hands, the soles of the feet and the neck upward.

If a person has never been infected with scabies before, symptoms appear approximately 4 to 6 weeks after infection. If a person has been infected with scabies before, they will begin to experience symptoms within 1 to 4 days after infection, because of previous exposure to scabies.

A person is considered infectious from the time they become infected until treatment is successfully completed. Linens and clothing are considered infectious until treatment or until 2 weeks after the last exposure. After treatment, a person may unknowingly become re-infested through exposure to the primary source of contact or contact with a different infested source.

How is scabies diagnosed?

• Microscopic exams of scrapings from suspicious lesion(s)
  Scrapings are placed on a slide and examined under a microscope to determine whether scabies are present.
• Burrow Ink Test (BIT)
  The suspicious area is rubbed with ink from a fountain pen. The surface is then wiped off with an alcohol pad; if the person is infected with scabies, the characteristic zigzag or S pattern of the burrow across the skin will appear.
• Topical Tetracycline solution
  A topical tetracycline solution may be applied to the suspicious area as an alternative to the BIT. The excess solution is wiped off the area with alcohol and examined under a special light to see if the characteristic zigzag or S pattern of the burrow appear.
• Shave Biopsies
  A very fine layer of skin is shaved off at the possible site of infestation and examined under a microscope for evidence of mites.
• Needle extraction of mites
  A needle is carefully inserted into the length of the burrow where the mite is likely living. The mite is then extracted with the needle and placed on a slide to be examined under a microscope.

How is it treated?

Recommended Treatment

• Permethrin cream (RID®; A-200®)
  The cream is applied in a thin layer to all areas of the body from the neck down.
  Rinse off after 8 to 14 hours.

Alternative Treatments

• Lindane (Kwell®)
  The cream is applied in a thin layer to all areas of the body from the neck down.
  Rinse off after 8 hours.
  NOTE: Lindane (Kwell®)is potentially harmful and may cause central nervous system complications, especially in children under the age of two. Lindane should not be used immediately after a bath or on broken skin. Lindane is not recommended to be used by the following people:
  
  • women who are pregnant or lactating
  • children under 2 years of age
  • people with seizure disorders
  • people with extensive dermatitis or known allergies to any ingredients found in Lindane.
• Ivermectin
  An oral treatment for scabies. The medication is taken once initially and again after two weeks.
  NOTE: Ivermectin is not recommended for treatment of pregnant or lactating women. It is unknown whether Ivermectin is safe for children who weigh less than 30 pounds.

Getting Rid of Scabies

• Use medication as directed.
• Notify and treat all partners and household members.
• Abstain from intimate or sexual contact until treatment is completed successfully.
• Wash infested clothing and linen on the hot cycle setting (130 degrees F). Dry on hot cycle for at least 20 minutes.
• Infested articles that cannot be laundered may be dry-cleaned or placed in a bag for 2 weeks to ensure decontamination.
• Furniture and carpeting may be vacuumed to rid infested area of mites. Dispose of vacuum bag afterwards.
• Fumigation of living areas is not necessary.
• Retest for cure is advised if new burrows or rashes appear. Current rashes and itching may continue for 2-3 weeks even after successful treatment. It is recommended to reduce exposure to all STIs.

What does it mean for my health?

Scabies doesn’t usually cause anything more than discomfort and inconvenience. Occasionally, secondary bacterial infections may occur due to aggressive scratching.