Easy-to-read medicine information about permethrin – what it is, how to use permethrin safely and possible side effects. Permethrin is also known by the brands names A-Scabies and Lyderm.
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What is permethrin?
Permethrin is a treatment for scabies. Scabies is an intensely itchy skin rash, which is caused by an allergic reaction to a tiny insect (called a mite). Permethrin is an insecticide that kills the scabies mite preventing its spread. Read more about scabies.
In New Zealand, permethrin is available on prescription from your doctor or can be bought from your pharmacy without a prescription. It is available as:
- A-Scabies (which is a lotion)
- Lyderm (which is a cream).
Both the lotion and cream are effective in killing the scabies mite. The choice is personal preference.
How to apply permethrin?
- Apply permethrin when your skin is cool and dry, so if you have just had a bath or shower, wait for a little while to let your skin cool before applying it.
- Permethrin must stay on the body for at least 8 hours (up to 12 hours) to kill the mites. It is best applied just before going to bed to avoid it being washed off.
- If a part of the body such as your hands are washed within 8 hours of applying permethrin, you will need to re-apply it immediately.
Permethrin must be applied to the whole body
Apply permethrin to every patch of skin over the whole body, from head to toe, including the scalp, face, neck, ears down to the soles of the feet.
- Make sure you apply to the areas between the fingers and toes, wrists, armpits, belly button, genitals and buttocks.
- Also, apply permethrin under the finger and toenails – use a nail brush if necessary.
- Do not wash your hands after applying the treatment.
- Women also need to apply permethrin under the breasts and around the nipples, as the scabies mite can burrow in these areas as well.
- If it's easier, you can ask someone else to apply the cream or lotion for you. This will make sure your whole body surface is covered with permethrin.
- Leave the lotion or cream on overnight (8-12 hours) then wash off in the morning, and wear clean clothes.
- Avoid getting permethrin in your eyes: if it does get into your eye, rinse your eye with plenty of water immediately.
- Avoid applying to broken skin, such as on cuts, grazes or sores, or to skin that has an infection.
- Breastfeeding: if you are breastfeeding a child, wash off the permethrin from your nipples before you breastfeed, and then re-apply afterwards.
- Itching may continue: permethrin kills the scabies mite preventing its spread but it does not relieve the itching. The itching is caused by an allergic reaction to the scabies mite and can continue for up to four weeks after treatment. Ask your doctor or pharmacist about medicines to relieve itching.
- Everyone living in the same household must be treated: scabies is contagious and spreads to others through close contact. It's important that everyone living in the same household with the infested person is treated at the same time, even if they are not itchy.
- Children under two years old and pregnant women: may have a different treatment and so should see a doctor first for advice.
- Repeat the treatment: another application of permethrin treatment is needed, one week to two weeks later. Don’t apply permethrin treatment more than twice without medical advice. Overuse can irritate the skin.
- Ask your pharmacist how much to apply. As a guide:
- most adults need one 30mL bottle of lotion
- larger adults may need two bottles
- children 5-12 years may only need half a bottle
- younger children 2-5 years, a quarter of a bottle.
- children under 2 years should see their doctor for advice.
- Wash clothes and bedding 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 a plastic bag for 7 days at room temperature, or
- seal in a plastic bag and freeze overnight.
- If you don’t do these things, the mites will come back.
- Note: the mite is not small enough to go through the weave of sheets, so under blankets and mattresses do not require laundering.
Possible side effects
Permethrin can cause skin irritation at the site of application, such as burning, stinging or tingling, numbness, redness and swelling. This should settle after a few hours. If it continues or becomes troublesome, tell your doctor or pharmacist.
See your doctor if:
- there is still itch 6 weeks after finishing the treatment
- you think the scratched areas have become infected.
- Permethrin New Zealand Formulary