Scabies (mate māngeongeo riha) is a very itchy skin rash. It is caused by a reaction to a tiny insect called a mite, which burrows under your skin. Scabies is easily spread and will not go away without treatment.
Key points about scabies
- Scabies is spread through skin-to-skin contact with a person who has scabies, or through shared bedding or clothing.
- You need to treat scabies with a lotion or cream called permethrin. It won’t go away on its own.
- Everyone who lives in the same household as the infested person needs to be treated at the same time.
- Wash all clothing and bedding in hot water after treatment.
- The itch may continue for a few weeks even though the mite is gone.
- See your doctor if itchiness continues for longer than 6 weeks.
What causes scabies?
Scabies is caused by tiny insects (mites), which burrow along just under the surface of your skin, laying eggs as they go. Scabies mites are so tiny you can't see them. Scabies is a reaction to the mites, mite poo (faeces) and mite eggs. Small blisters grow on your skin and your skin gets very itchy. The redness and small blisters look like a rash on your skin.
How do you get scabies?
Anyone can get scabies. It is more common when you have lots of people in close contact. Outbreaks occur in places such as early childhood centres. Washing with soap will not prevent or cure it.
Scabies is usually spread by direct skin-to-skin contact with a person who has scabies. Contact generally needs to be ongoing – you are unlikely to get scabies from a quick handshake or hug.
Scabies is spread easily to household members and sexual partners. Scabies can also be spread by sharing clothing, towels or bedding used by a person with scabies.
How do you know if you have scabies?
One of the first symptoms of scabies is a very itchy rash. This is usually worse when you are warm, such as when you are in bed or after a shower.
Symptoms generally start 3–6 weeks after infestation with the scabies mite. However, if you’ve had scabies before, the rash can start after only 1–3 days.
- The scabies rash generally looks like lots of small red bumps.
- The rash can appear anywhere on your body.
- The most common places for the rash are between your fingers, on your wrists, inside your elbows, around your waist, on your bottom or genitals (private parts) and in your armpits.
- The rash does not usually appear on your head (except for very young children).
- Other conditions can cause a similar rash, so it can easily be confused with other skin conditions such as dermatitis or hives.
Not all people who have the scabies mite have itching. You can spread scabies, even if you do not have symptoms, until you are successfully treated and the mites and eggs are killed. Talk to your doctor, a nurse or a pharmacist if you think you might have scabies.
Images of scabies
See more images of scabies from DermNet, NZ.
Why is it important to treat scabies?
See your doctor again if the sores or rash get redder, warm, start swelling or have pus, or if you get a fever (high temperature). This could mean you have a skin infection that needs treating with an antibiotic or other medicine.
How is scabies treated?
Scabies is usually treated with a cream or lotion called permethrin. Permethrin is an insecticide that kills the scabies mite. You can buy this from your pharmacy or get it on prescription from your doctor. You need enough cream/lotion to treat everyone in your household. One 30 gram tube is generally enough for an average sized adult.
|Permethrin may not be suitable for everyone – you may need a different treatment|
See you doctor for advice before treatment if you:
How to apply permethrin cream/lotion to treat scabies
Everyone living in your house should be treated at the same time even if they are not itchy.
- Permethrin must stay on your body for at least 8 hours (and up to 12 hours) to kill the mites.
- Apply the cream/lotion just before going to bed. Make sure your skin is cool and dry.
- Cover every patch of skin on your body, including your scalp, face, neck, ears and right down to the soles of your feet. Pay particular attention to the areas between your fingers and toes, wrists, armpits, belly button, genitals and buttocks.
- Leave the cream/lotion on overnight.
- If you wash your hands during the night, reapply cream/lotion to your hands.
- In the morning have a shower and wear clean clothes.
Another application of permethrin treatment is often needed 1–2 weeks later. Don’t apply permethrin treatment more than twice without medical advice. Overuse can irritate your skin. You or your child can go back to work or school 24 hours after the first treatment. Read more about permethrin.
On the morning after everyone in your household has been treated
Wash all clothing, sheets, towels and pillowcases anyone has used in the past week in hot water (50°C for at least 10 minutes). If you have a tumble drier, dry all items on the hottest tumble dryer setting for 20 minutes.
If clothes or linen cannot be washed either:
- dry clean, or
- seal in plastic bag for 7 days at room temperature, or
- seal in plastic bag and freeze overnight.
If you don’t do these things, the mites will re-infest your family/whānau. Note: The mite is not small enough to go through sheets, so under-blankets and mattresses do not need to be cleaned.
I have used scabies treatment – why am I still itchy?
Although the treatment kills the scabies mites quickly, the itching can carry on for a few weeks. The intense itch generally improves after 1 week of treatment. However, it can take 4–6 weeks for the itch and rash to clear completely, even though all mites have been killed.
Treat itchy patches with antihistamines, moisturisers or mild steroid creams. Crotamiton cream (Eurax®, Itch-Soothe®) is a weak scabicide that can be used to reduce itch. Preparations containing calamine often do not work and may increase dry skin.
See your doctor if your skin is still itching 6 weeks after treatment.
Other reasons you may still be itchy
- The diagnosis may be incorrect. Scabies can be confused with a number of other skin conditions, particularly dermatitis and hives. Coeliac disease is another cause of an ongoing itchy rash.
- You may need to repeat the scabies treatment. Ask your pharmacist or doctor for advice. Do not repeat treatment more than 2 times without medical advice. Overuse of insecticides such as permethrin can irritate your skin.
- Resistance to treatment. Scabies occasionally appears to be resistant to the prescribed scabies treatment. You may need to try a different treatment. Ask your doctor about this.
|Jeremy Steinberg is a GP with special interests in musculoskeletal medicine, evidence-based medicine and use of ultrasound. He's been reviewing topics for Health Navigator since 2017 and in his spare time loves programming. You can see some of the tools he's developed on his website.