SCABIES

Nov 2, 2018

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

"Pants Dad, pants." I ignore Emily. We have this discussion often. She doesn't approve of me walking around the house with no covering on my legs. I, however, had an urgent appointment with the coffee maker. "How hard is it for you to just put on pants in the morning?" More ignoring. And for the record, my pants were in the kitchen, near the coffee maker. "Really Dad?" Okay. Got my coffee. Ah ha! I finally see what she is wearing! I might win this one! And I'm itching to finally win one against Emily.

The path to an itch free morning can take you through scabies territory. Scabies is a contagious infestation of the skin caused by the human mite called Sarcoptes scabiei. The scabies mite is almost too small to be seen with the naked eye. The mites burrow under the skin so they are almost never seen. Over 100 million people worldwide have scabies, and it is most commonly seen in people living or working in very crowded conditions. Schools are not usually crowded enough to promote transmission. Scabies is most commonly transmitted by close personal contact (i.e. usually by skin to skin contact). It is uncommon to spread scabies through objects like sharing clothing, bed linens and other objects. The pregnant female mite burrows 0.5 to 5 mm per day through the top layer of skin and lays two to three eggs per day. Three or four days later, the eggs hatch and the larvae travel to the skin surface and mature into adult mites in 14 to 17 days. The smaller male mite lives on the skin surface and dies shortly after mating. The female mite lives about 30 days. If it is a person's first time with scabies, they will usually have 10 to 15 mites living on them. If they have had scabies before, they will usually only have 5-8 mites living on them. Mites can only live separated from a host person for 1 to 2 days.

The most common symptom of scabies is itching. It can be quite severe and worse at night. If this is the first infestation a person has with scabies, the itchiness may not occur until weeks after the infestation. The itchiness is due to sensitization to the mites, eggs and feces. If a person has had scabies before, the itchiness can happen as early as 24 hours after infestation. As the female digs through the skin, she leaves behind a burrow. The burrows look like tiny lines or waves in the skin 2-5 mm long. The burrow lines don't appear on every patient, but if you can see the wavy lines it is easier for the doctor to confirm the itch is from scabies. In adults, the itch and rash don't appear on the face or scalp, but in young children they can. Excessive scratching can lead to secondary infections like impetigo.

What do you do if someone in your house is very itchy, especially at night? See the doctor for a diagnosis. After the diagnosis of scabies is confirmed, we should treat the infested person and their close physical contacts at the same time, whether or not symptoms are present. Remember some people can have scabies for weeks before they start itching, and they are still contagious during that time. Permethrin 5% cream is the preferred agent for anyone over 2 months old. It seems to be effective about 90% of the time. We tell people to use the permethrin cream before bed. We tell the person take a warm (not hot) bath or shower, and dry off. They should massage the cream into the skin from their neck down to the soles of their feet. They should pay special attention to areas between fingers and toes, under fingernails, wrists, armpits, buttocks, and external genitalia. After applying the cream, they should put on clean clothing, put clean sheets on the bed and climb in. The cream should be washed off in the shower or bath after 12 to 14 hours. Usually one treatment will kill off the scabies, but a second treatment 7-10 days later is becoming a standard recommendation. The itchiness will take 1-2 weeks to go away, and is not a sign that the scabies treatment isn't working. A child is safe to go to school the day after using the first dose of permethrin cream. Even after the permethrin 5% cream is applied, itching is often still a problem. Steroid creams like betamethasone and oral antihistamines like diphenhydramine or Benadryl are often prescribed with the permethrin 5% cream.

There are less commonly used alternatives to 5% permethrin cream. We have compounded a sulfur cream under the direction of a physician in the past. It also works, but it is messier and smellier than permethrin. It is less convenient as it has to be applied for 3 days in a row. But the sulfur ointment is an effective alternative to permethrin. Another commercially available alternative to permethrin 5% cream is crotamition or Eurax cream. It is considered less effective than permethrin 5% cream and it has to be applied daily for 2 days so it is less convenient.

What about cleaning the house, bed linens and yourself? Start by trimming finger and toe nails to make sure there aren't mites hiding there. Then wash clothes and linens in soap and hot (60 C) water. Items that can't be washed should be dry cleaned, or put in a plastic bag for a week. The mite doesn't survive for more than two days off of people. All surfaces, rugs, and furniture should be vacuumed. There is some controversy about how likely it is to get scabies from inanimate objects like bed sheets. The easiest way to get scabies is from skin to skin contact with a person who has scabies. Although there are documented cases of people getting scabies only through touching bed sheets, it is apparently much more difficult than through contact with a person.

I looked up. Emily was wearing tights! "Hey! Pants, Emily pants!" "I'm wearing leggings Dad." "Yes, well leggings are tights. And tights are not pants." Emily looked perplexed. She seemed unaware of the scathing expose. You see the CBC Sketch Comedy group The Irrelevant Show did an episode on this very subject. Written by Diana Frances, cast member Jana O'Connor clearly explains that tights are not pants. Instead of citing medical literature, I thought it was appropriate reference this Edmonton based Sketch Comedy Troupe for a debate with a teenaged girl. And I learned something valuable during that debate. If someone is frustrated enough, you can actually hear their eyes roll.

The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.

As always if you have any questions or concerns about these or other products, ask your pharmacist.

We now have this and most other articles published in the Parkland Shopper on our Website. Please visit us at www.dcp.ca

Tight are Not Pants - The Irrelevant Show - https://www.cbc.ca/player/play/2668567696

 


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