Permethrin cream contains an insecticide. It kills insects (parasites) that live on humans, such as the scabies mite and crab (pubic) lice. Two applications of treatment with permethrin cream are needed, one week apart. Your whole body should be treated both times.

What is it?

  • Scabies is an itchy skin disorder that leads to a rash. It is caused by an infestation with a parasite - the scabies mite. The mite lives on the skin and burrows into it. Scabies is contagious and spreads to others through close skin-to-skin contact. The hand is the most common site to be first affected, probably from prolonged hand-holding with an infected person. Close skin-to-skin contact when having sex is another common way of catching scabies.
  • Crab lice are tiny insects that live on humans, usually in the pubic hair. They are passed on through close body contact, such as when having sex. Infestation with pubic lice can cause itching but not everyone affected has symptoms. Crab lice are grey or brown in colour. They get their name because some of their legs have crab-like claws.
  • Permethrin cream is available on prescription, or you can buy it without a prescription at a pharmacy.
It is easy to apply and normally works well if used properly.

Before using permethrin cream

  • To make sure this is the right treatment for you, before you start using permethrin cream it is important that your doctor or pharmacist knows:
  • If you are pregnant or breast-feeding. This is because, while you are expecting or feeding a baby, you should only use medicines on the recommendation of a doctor.
  • If it is for a child or teenager under 18 years if age. Permethrin cream should only be used for scabies on the advice of a doctor in children under 2 years of age. It can be used for crab lice, only in adults.
  • If you have ever had an allergic reaction to a cream or ointment, or if you know you are allergic to chrysanthemums or flowering plants known as Compositae.

How to use permethrin cream

  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about applying permethrin cream and will provide you with a full list of the side-effects which you could experience from using it.
  • Two applications of treatment are needed, one week apart. Apply a thin layer of the cream over your whole body including your face, neck, scalp and ears, but try to take care not to get any into your eyes. Remember to include awkward places such as your back, the soles of your feet, between your fingers and toes, under your fingernails, and your genitals. The cream should be applied 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 you apply the cream.
  • If you have scabies, pay special attention to the areas where mite burrows can commonly occur - the front of your wrists and elbows, beneath your breasts, your armpits, and around the nipples in women.
  • Leave the cream on for 8-12 hours for scabies, or 12 hours (overnight) for crab lice. After this time, you should remove the treatment from your skin by having a bath or a shower. If you need to wash your hands during the treatment time, remember to re-apply some cream to your hands afterwards. You will need to use the cream a second time, seven days after the first treatment. Apply the cream in the same way as the first time. Using two treatments, a week apart like this, helps to ensure that all the mites/lice are killed.
  • For the two applications, an adult is likely to need 60 g of cream (two tubes - one tube for each application), older children will require 30 g cream in total (½ tube for each application) and younger children will require 15 g cream in total (¼ tube for each application).
  • Please note - if you are breast-feeding a child, you should wash off the cream from your nipples before you breast-feed, and then re-apply the cream afterwards.

Getting the most from your treatment

  • If you have scabies, all your household members, close contacts, and sleeping/sexual partners should also be treated - even if they have no symptoms. This is because it can take up to six weeks to develop symptoms after you become infected. Close family and partners may be infected but have no symptoms, and may pass on the mite. Everyone who is treated, should be treated on the same day.
  • If you have crab lice, your recent close contacts and sexual partners should also be treated if they are infected. It is important to remember that lice may be present even without other symptoms such as itching. If you have caught crab lice from a sexual partner, you should also be tested for other sexually transmitted infections.

If you have scabies, the following also applies:

  • If you are applying permethrin cream to an infant or young child, put mittens on your child to stop them licking the cream off their hands. Don't apply the cream to areas around their mouth where it could be licked off.
  • Children should stay off school until the first application of treatment for scabies has been completed.
  • Clothes, towels and bed linen should be machine-washed at 50°C or above after the first application of treatment. This kills the scabies mites. Keep any items of clothing that cannot be washed, in plastic bags for at least 72 hours to contain the mites until they die. Alternative options to kill any mites on clothes and linen are ironing the item with a hot iron, dry cleaning or putting items in a dryer on the hot cycle for 10-30 minutes. It is not necessary to fumigate living areas or furniture or to treat pets.
  • You will still be itchy for a while after successful treatment. If the itching becomes troublesome to you, your doctor or pharmacist will be able to advise you regarding suitable products to ease this. Moisturising creams can provide temporary relief from itching.
  • It is normal for it to take up to 2-3 weeks (and sometimes up to six weeks) for the itch to go completely after scabies mites have been killed. You should, however, see a doctor if the itch persists longer than 2-3 weeks after treatment. This is because sometimes the first insecticide does not work and you may need to use a different one.
  • Some people may develop a secondary skin infection which may need antibiotic treatment. If you suspect this is the case for you, you should make an appointment to see your doctor.

Can permethrin cream cause problems?

  • Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with permethrin. You will find a full list in the manufacturer's information leaflet supplied with the cream. The unwanted effects often improve as your body adjusts to the new medicine but speak with your doctor or pharmacist if any of the following continue or become troublesome.

If you experience any other symptoms which you think may be due to the cream, please speak with your doctor or pharmacist for further advice.

References:

http://patient.info/medicine/permethrin-cream-lyclear

https://www.medicines.org.uk/emc/medicine/16356

http://www.netdoctor.co.uk/medicines/skin-and-hair/a7047/lyclear-dermal-cream-permethrin/

https://www.drugs.com/uk/lyclear-dermal-cream-spc-4930.html