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Column originally published Sep 25, 2018

Treatment Of Scabies Needs To Be Thorough

Question: We have been looking after my aging parents. They live in the granny suite next to our home, and we have dinner together every night. My mother has an itchy rash on her hands for over a month. I finally got an appointment to see her family doctor yesterday. After examination, he said that my mother likely has scabies. He got some scraping and sent it to the laboratory. We won’t get any result until next week. Our son also developed an itchy rash all over his body in the last week. I wonder where she got the scabies, and whether our son has it too.


It is difficult to know with certainty where your mom picked up scabies; it is not related to personal hygiene. It is an infestation caused by a tiny mite called Sarcoptes scabiei. Adult mites are less than 0.5 mm in size; we cannot see them with our eyes.

Female mites dig shallow tunnels in our skin, and deposit eggs and droppings inside. Within days, the eggs will hatch. Immature mites feast on skin cells, and morph into adults over the next few weeks, and the cycle continues.

The rash and itch of scabies is the result of our body’s reaction to the mites. Scabies is also called “seven year itch.” The infestation lasts a very long time, unless one gets effective treatment.

The rash is usually red, and can be in small groups. It is most often found in the web between fingers, the wrists, elbows, armpits, behind the knees, around the waist, the umbilicus, buttocks, genitalia, and around nipples in women. It is extremely itchy, and almost impossible not to scratch. Secondary bacterial infection from scratching is very common. In adults, scabies usually don’t affect the face and scalp. However, in young children, it can affect all parts of the body.

Scabies is spread through prolonged person-to-person contact; it doesn’t spread through handshake. Outbreaks have occurred in daycares, schools, hospitals, nursing homes, and long-term-care facilities. Occasionally, it can spread through towels and beddings. Scabies cannot survive for more than a few days away from our body.

This scabies mite is specific for humans. Cats and dogs have their own species of mites, and they don’t affect us.

When we contract scabies for the first time, it takes 2 to six weeks before the rash and itch appears. However, we react to a second infestation much faster; the rash can show up in a few days.

Doctors can diagnose scabies by examining skin scraping for mites, eggs, and droppings under the microscope. It is also possible to use a marker over the rash, then wipe off the markings with an alcohol swab. The ink can seep into the tunnels to make them visible.

The most effective treatment is a medicine called permethrin. It is related to chemicals found in the flowers of chrysanthemum. A 5% permethrin cream or lotion should be applied all over the body from the neck down, between the fingers and toes, underneath finger nails, on the skin at the genitalia, and between the buttocks. It is important not to miss any area. Adults likely need to help each other on the back. Children need parents to ensure it is applied properly. Your senior parents may need your help also. Your toddler son needs the medicine on his face and scalp, because scabies can affect these areas in young children.

The best time to do this is in one evening for the whole family, after a warm bath or shower. Put on clothes that have not been worn for at least 4 to seven days. All pillow covers and bed linens should be changed before going to bed.

Leave the medicine on until the next morning, for 8 to twelve hours; take another shower to wash off the medicine. Put on fresh clothes and fresh linens like the night before. All the clothes and beddings should be washed in hot cycle, and use high heat in the dryer. If dryer is not available, they can be dried on clothesline.

Anything that cannot be washed should be placed in a bag and isolated for one week; the mites will die in the meantime. Some recommend vacuuming the whole house, although I am not sure it is necessary. Some doctors recommend a second treatment after 4 to seven days.

It is important to know that itching and rash will continue for days to weeks after treatment. An antihistamine can reduce the itching, especially at night. If there is bacterial secondary infection, antibiotics may be necessary.

If your parents go to senior activity groups, it is important to inform them of your mom’s condition. If your toddler son goes to daycare, you need to inform them too. Other seniors and other children in daycare can be infested with scabies. Your mom or your son could have picked it up from there also.