Pubic lice (Phthirus pubis) are tiny parasitic insects that live on coarse human body hair, such as pubic hair. They spread through close body contact, most commonly sexual contact. After you get pubic lice, it can take several weeks before symptoms appear.
As well as being found in pubic hair, the lice are also sometimes found in:
*underarm and leg hair
*hair on the chest, abdomen and back
*facial hair, such as beards and moustaches
*eyelashes and eyebrows (very occasionally)
Pubic lice are sometimes called crab lice because they look similar to crabs. Adult lice are about 2mm long and are yellow-grey or dusky red in colour. The lice attach their eggs (or nits) to the base of hairs.
The lice do not transmit HIV or other sexually transmitted infections (STIs), but a sexual health check-up is always recommended if you have pubic lice.
Pubic lice are not the same as head lice and do not live in the hair on your scalp.
How do you get pubic lice?
Pubic lice are not linked to poor personal hygiene. They are spread through close body contact with someone who has them.
The lice crawl from hair to hair, but cannot fly or jump. They need human blood to survive, so generally only leave the body to move from one person to another.
They are most commonly passed on during sexual contact. Condoms will not prevent them being passed to another person.
It is also possible for pubic lice to be spread through sharing clothes, towels and bedding.
When to seek medical advice
If you think you may have pubic lice, go to your GP or your nearest sexual health clinic, also known as a genitourinary medicine (GUM) clinic, for a check-up as soon as possible.
It is usually easy to diagnose pubic lice by examining the affected area. The doctor or nurse may use a magnifying glass to look for signs of the lice, such as pale-coloured eggs or the lice themselves.
If you have pubic lice as a result of sexual contact, you should be tested for other sexually transmitted infections (STIs).
Find your local sexual health services. [link]
Complications of pubic lice
A pubic lice infestation can sometimes lead to minor complications, including skin and eye problems.
If you have pubic lice, your skin may become irritated from scratching.
Scratching can cause scratch marks on your skin, or it could lead to an infection such as impetigo (a contagious bacterial skin infection) or furunculosis (boils on the skin).
Eye infections, such as conjunctivitis, and eye inflammation, such as blepharitis, can sometimes develop if your eyelashes have been infested with pubic lice.
After you come into contact with pubic lice, it can take several weeks before symptoms appear. Some people don’t have any symptoms, or may not notice them.
The symptoms of pubic lice are the same for both men and women, and include:
- itching in the affected areas, which may be intense
- inflammation and irritation in the affected areas caused by scratching
- black powder in your underwear
- blue-coloured spots on your skin where the lice are living, such as on your thighs or lower abdomen (these are caused by lice bites)
- small spots of blood on your skin that are also caused by lice bites
Itching is the most common symptom of pubic lice. However, it can take several weeks after the first infestation for you to notice any itching.
The itching is not caused by the lice biting you – it’s an allergic reaction to the louse saliva.
The itching is usually worse during the night, when the lice are more active.
Pubic lice and eggs
Adult pubic lice are very small (about 2mm long) and difficult to see. The lice are yellow-grey or dusky red in colour and have six legs. Two of the legs are larger than the others and look like the claws of a crab. The lice use these to grasp onto hairs.
The lice lay their eggs (nits) in sacs that are firmly stuck to hairs and are a pale brownish colour. When the eggs hatch, the empty sacs are white. Although pubic lice and lice eggs are very small and not easy to see, they may be visible in coarse hair anywhere on your body (apart from the hair on your head).
You may also find empty white eggshells on your hairs, although this does not necessarily mean that you still have an infestation of pubic lice.
Pubic lice can be treated at home with insecticide cream, lotion or shampoo. It will usually need to be applied once and repeated after three to seven days.
Some treatments only need to be applied to the affected area, but sometimes the whole body must be treated, taking care to avoid the eyes. Your doctor, nurse or pharmacist can give you more advice about this.
Everyone you have had close bodily contact with should also be treated at the same time. This includes any sexual partners you have had in the past three months and all members of your household.
Sometimes pubic lice can be difficult to get rid of because they can develop resistance to insecticide treatments. If this is the case, you may need to try more than one type of treatment. Your doctor or pharmacist can advise you on suitable alternatives.
Washing clothing and bedding
It’s important to wash any clothing and bedding, including towels, in a washing machine. This should be on a hot cycle (50ºC or higher) to make sure the lice are killed to help prevent reinfection.
You can treat yourself at home with an insecticide cream, lotion or shampoo. They are available on prescription from your doctor, or you can buy them over the counter from your pharmacy.
Before using the treatment, speak to your doctor or pharmacist about the correct way to use it. Follow their instructions, even if they are different to those on the packaging.
Always ask for advice if the treatment is for:
- a child under 18 years of age
- someone who is pregnant or breastfeeding
These people may require a specific type of treatment.
Applying a lotion, cream or shampoo
In most cases the instructions for using a lotion, cream or shampoo will be as follows:
- apply the product to the affected area, particularly any hairy areas, such as your eyebrows, beard or moustache – depending on the product, you might need to apply it to your whole body, including the scalp, neck, ears and face
- be careful not to get the product in your eyes – if you do, rinse your eyes thoroughly with water
reapply the treatment if you wash any part of your body during the treatment time
- after the correct treatment time (stated on the packet) has passed, wash the lotion or cream off
repeat the treatment after three to seven days as instructed
- Do not use the medication more than twice.
Treating an eyelash infestation
If your eyelashes are infested, seek specialist advice and help from your doctor.
You cannot use the same insecticide lotion or cream that you use on your body as this will irritate your eyes. Your doctor will be able to recommend an alternative treatment for you.
An eye ointment with a white or yellow soft paraffin base may be recommended. This works by coating the lice in the greasy ointment and suffocating them. You should:
- apply the ointment to your eyelashes twice a day, ensuring that all your eyelashes are well covered
each time you reapply the ointment, first gently wipe your eyelashes and eyelids clean with a tissue, and * * * throw the tissue away afterwards
- continue the treatment for at least eight days
- continue the treatment for 10 days if you can still see lice or unhatched eggs (not empty eggshells or dead nits) – the eggs can take this long to hatch
Insecticides that are used to treat pubic lice may cause skin or eye irritation, such as itchiness, redness, stinging or burning.
If you have these side effects, wash the insecticide off the irritated area. If the insecticide gets into your eyes, rinse them thoroughly using plenty of water.
Some aqueous and alcohol-based medications may discolour permed, coloured or bleached hair. Check the patient information leaflet for more details.
The first treatment application will probably kill the lice, but the eggs may not have been destroyed. This means that more lice could hatch and the cycle will start again.
Reapplying the treatment after seven days ensures that any lice are killed before they are old enough to lay more eggs.
Check for lice a week after your second treatment, or return to your doctor, sexual health clinic or genitourinary medicine (GUM) clinic so they can check for you. If you find empty eggshells (dead nits), it does not necessarily mean that you are still infested. They can remain stuck to the hairs even after treatment. Sometimes lice may be resistant to the treatment used and your doctor may recommend a different treatment.
To prevent pubic lice infestation, avoid having sexual contact or sharing bedding or clothing with anyone who has an infestation. However, your sexual partner may not know or may not tell you that they have public lice. In this case, it’s difficult to avoid getting pubic lice as close bodily contact can spread them.
If you have pubic lice, and in order to prevent re-infestation, anyone that you are in close contact with should also be treated at the same time as you. This includes your sexual partners and all members of your household, even if they do not have symptoms.
Infestations from sexual contact
Staff at the GUM clinic will recommend that you inform any sexual partners you have had in the past three months so they can also be examined for pubic lice and treated if necessary.
Some people feel angry, upset or embarrassed about talking to their current or former sexual partners about pubic lice. Do not be afraid to discuss your concerns with clinic staff. They can help you decide the best way to make contact. They can also contact a partner without releasing your details, if you prefer.
When can I have sex again?
Avoid having sex (vaginal, anal or oral) or close bodily contact until both you and your partner have finished the course of treatment, including any follow-up treatment. This is to avoid reinfection or passing the infection on to someone else.