What are anogenital warts and what causes them?
Anogenital warts are sometimes just called genital warts. They are small lumps that develop on the genitals and/or around the back passage (anus). They are caused by a virus called the human papillomavirus (HPV). There are over 100 types of this virus. Most anogenital warts are caused by types 6 or 11. Common warts that many people have on their hands and feet are caused by a different type of HPV.
How do you get anogenital warts?
The virus is passed on by sexual contact. You need close skin-to-skin contact to pass on the virus. This means that you do not necessarily need to have penetrative sex to pass on infection. Sharing sex toys may also pass on infection. Very rarely, anogenital warts may be passed on from hand warts. They may also rarely be passed on to a baby when a woman gives birth.
It can take weeks or months to develop warts after being infected with HPV. Also, most people infected with HPV do not develop warts. You can be a carrier of the virus without realising it and you may pass on the virus to others who then develop warts. It is also possible to pass on the virus after warts have been treated or gone.
Because it can take some time to develop warts after being infected with HPV, if you have just developed noticeable anogenital warts, it does not necessarily mean that either partner has been recently unfaithful. You may have had HPV for a long time without developing warts.
Also, note that you may get anal warts even if you have not had anal sex.
How common are anogenital warts?
of people would be worried about contracting genital warts from a casual sexual encounter.
Source: Patient Sexual Health Survey
They are common and are one of the most commonly diagnosed sexually transmitted infections (STIs) in the UK. Many more people are infected with the virus but do not develop visible warts (they are carriers).
An individual has quite a high chance of having HPV infection in their lifetime. However, most people do not know that they have been infected because they have no symptoms. Therefore it is difficult to know exactly how common it is. Only a few people with HPV infection develop anogenital warts. Around 3 in 100 people are treated for genital warts per year in the UK.
Where do anogenital warts develop?
In men, the warts usually develop on the outer skin of the penis. In women, the warts usually develop on the vulva, just outside the vagina. Warts may also develop on the skin around the back passage (anus), both in men and in women.
Sometimes warts develop inside the vagina, on the neck of the womb (cervix), on the scrotum, or inside the anus. They also sometimes occur inside the tube that drains urine from the bladder to the outside (the urethra). Rarely, they occur in the mouth or nose.
What do anogenital warts look like?
Anogenital warts may have several different appearances. There may be one or more. Sometimes individual warts join together to join one large warty area. They may look like small, skin-coloured lumps on the skin (similar to the common warts that many people have on their hands). Others may be red or pink, grey or white. Warts that develop on skin that is warm, moist and non-hairy (such as the vulva) tend to be soft. Warts that develop on skin that is dry and hairy (such as around the bottom) tend to be firm.
The number of warts that develop varies from person to person. Some people have just a few that are barely noticeable. Some people have many around their genitals and anus.
By SOA-AIDS Amsterdam, via Wikimedia Commons
What are the symptoms of anogenital warts?
Often there are no symptoms, other than a lump on the skin being noticed. In most cases, the warts cause no physical discomfort. They sometimes cause irritation and soreness, especially if they occur around the back passage (anus). Sometimes the warts can bleed or cause pain on intercourse. If you have warts inside your anus, this can sometimes cause bleeding when you go to the toilet. If you have warts inside the tube from which your urine is passed (urethra), the stream of urine may be different, or there may be bleeding.
Warts look unsightly and some people become distressed by this. They may cause embarrassment, or interfere with sexual activity.
Do I need any tests?
Anogenital warts can usually be diagnosed by their typical appearance when you are examined by a doctor or nurse. Your doctor or nurse will examine your external genitalia to look for warts. They may also suggest that they do an internal examination of your vagina or back passage to look for warts here.
So, tests are not usually needed to confirm the diagnosis. However, around 1 in 5 people with anogenital warts also have another STI. Tests such as swabs are commonly advised to check for other infections - even if you do not have any symptoms.
If you have anogenital warts, in the UK your doctor or nurse will usually refer you to a sexual health specialist in a genitourinary medicine (GUM) clinic for tests and treatment. If you are worried that you may have anogenital warts or another STI, the best option is to visit a GUM clinic from the outset. You do not need a referral from your GP to attend a GUM clinic. You can ring the local hospital or health authority and ask where the nearest clinic is. Local and national information is also available on the internet - for example, from the Family Planning Association's 'Find a clinic' service.
The GUM clinic doctor or nurse will be able to diagnose your warts, and advise on treatment. They will also test you (and your partner if possible) for other infections. They will not normally write to your GP with your results unless you wish them to. All information about your visit to a GUM clinic is confidential and would only be shared with your GP with your permission. If the diagnosis is unclear, or if your warts are not getting better with treatment, you may occasionally need further tests. This usually involves taking a sample of the wart tissue to be looked at through a microscope (a biopsy).
What are the treatment options for anogenital warts?
There are a number of different treatments that can be used and they are described below. Whatever the treatment, it usually takes several weeks of treatment to clear the warts. Sometimes it can take up to six months of treatment.
Treatment may be a little uncomfortable and cause some irritation of the skin around the area that is being treated. Also, smokers tend to respond less well to treatment, so stopping smoking may be beneficial to your treatment. Sometimes, one treatment may not be successful. If this is the case, another treatment may be advised. There is also a chance that anogenital warts can return after treatment. This is because the treatments do not clear the HPV virus itself but just treat the warty lumps.
Wart treatments that are sold over the counter in pharmacies should not be used to treat anogenital warts.
One option is not to have any treatment. Anogenital warts are not serious but can be unsightly. Some people prefer just to leave them alone. There is a good chance that they will go without any treatment. In fact, about one third of visible warts disappear by themselves over six months.
A number of chemicals, when put on to warts, will burn or destroy the wart tissue.
- Podophyllotoxin is a chemical that comes as a cream or lotion. This may be prescribed for you to put on the warts at home. You should apply it twice-daily for three days, followed by four days' rest. This is repeated four to five times depending on the type of podophyllotoxin you are given (so the whole treatment lasts about four to five weeks). There are some points to note about podophyllotoxin:
- You must not use it if you are pregnant.
- You should not put podophyllotoxin on broken skin or open wounds and you should be careful to avoid getting it on normal skin around the warts.
- Sexual contact is not recommended soon after the cream/lotion is applied to your skin, as it may cause irritation for your partner.
- You should make sure you follow the instructions carefully when you are applying the cream/lotion and you should not apply too much. If you apply too much, the cream/lotion may start to have unwanted effects inside your body.
- Imiquimod cream is an alternative. You apply the cream to your warts at bedtime and wash it off 6-10 hours later. This is repeated three times per week for up to 16 weeks. It may take some weeks before the treatment works. There are some points to note about imiquimod cream:
- Imiquimod may weaken condoms and diaphragms so you should not rely on these as contraception whilst you are undergoing treatment.
- You must not use it if you are pregnant.
- Sexual contact is not recommended soon after the cream is applied to your skin, as it may cause irritation for your partner.
- You should not put imiquimod cream on broken skin or open wounds.
- You should be careful to avoid getting it on normal skin around the warts.
- In some people, imiquimod cream can cause permanent colour change to the skin where it is applied.
- Other chemicals may be advised if there is little success with the above. These are applied by the doctor or nurse in the clinic, rather than you applying them yourself at home.
Various techniques can destroy the wart tissue. They include:
- Freezing warts with liquid nitrogen. This is a common treatment which is called cryotherapy. Liquid nitrogen is sprayed on or applied to the wart. Liquid nitrogen is very cold. The freezing and thawing destroys the wart tissue. To clear the warts fully you may need several treatments, a week or so apart. This treatment may be used if you have a small number of warts. This is often a good option if you are pregnant.
- Having the warts cut off (surgical removal) under local anaesthetic. This may be an option if you have just a few warts that can be easily removed in this way.
- Electrocautery. This is a technique where the warts are destroyed by burning.
- A laser. This is another technique sometimes used to destroy the warts by burning.
Which is the best treatment?
Each treatment has pros and cons. The treatment decided upon depends on factors such as:
- How many warts are present. For example, cryotherapy is usually only used for small-to-moderate numbers of warts.
- Where the warts are. For example, some chemical treatments should not be used internally - such as on the neck of the womb (cervix), vagina or inside the back passage (anus).
- Your preference. For example, whether a home-based or clinic-based treatment is preferred.
- Whether you are pregnant. Some chemical treatments should not be used if you are pregnant
The surgical treatments (cutting, freezing, burning treatments) are generally the most successful. However, they are not always appropriate. Warts may come back whichever treatment is used.
What about my sexual partner?
Your current sexual partner(s) may wish to be checked to see if they have warts or other STIs. It is a good idea to advise your current sexual partner, and any partners from the previous six months, to be checked.
Is there a link between anogenital warts and cancer?
The types of HPV that most commonly cause anogenital warts (types 6 and 11) do not increase your risk of cancer. HPV types 6 and 11 cause over 9 in 10 cases of anogenital warts. However, some other types of HPV do increase your risk of developing cancer. You may have more than one type of HPV infection at the same time (one type that causes anogenital warts and one type that may increase your risk of cancer).
It is known that most cases of cancer of the neck of the womb (cervix) are caused by HPV infection. So, it is particularly important that women with anogenital warts have cervical screening tests at the usual recommended times and do not put it off. You do not need to have cervical screening tests more regularly if you have anogenital warts. See separate leaflet called Cervical Screening (Cervical Smear Test) for further details.
It also appears that the risk of other cancers is slightly higher if you have HPV infection. This includes other cancers in the genital area and some cancers of the mouth, throat and neck.
Prevention of anogenital warts
Condoms (male or female) may prevent genital warts from being passed on to new sexual partners who are not infected. However, they do not completely protect you from getting HPV infection as the skin that is not covered by a condom can become infected. But condoms do help to protect against other STIs such as chlamydia and HIV. You should also use condoms whilst having oral sex and you should not share sex toys.
When you are being treated for warts, it is commonly advised that you should use condoms when you have sex, until the warts have completely gone.
In the UK, the Department of Health originally chose a type of vaccine (Cervarix®) that did not protect against the common types of HPV that cause anogenital warts (types 6 and 11) in its national immunisation campaign. However, from September 2012 the vaccine used was changed to a type that covers HPV-6/11/16/18 (Gardasil®). See separate leaflet called HPV immunisation for further details.
It is hoped that by vaccinating teenage girls before they catch the HPV infection, the numbers of anogenital warts overall in years to come will be much reduced. This has already been shown to happen in countries such as Australia, which started vaccinating earlier.
What is the outlook?
Anogenital warts can usually be cleared with treatment. However, in about 1 in 4 cases, new warts develop at some time after successful treatment. This is usually because the same infection has re-activated, not because you have a newly acquired infection. If warts do come back, they can be treated in the same way.
Further reading and references
Sexually transmitted infections (STIs): surveillance, data, screening and management; Public Health England, 2016
Sexually Transmitted Infections in Primary Care; Royal College of General Practitioners and British Association for Sexual Health and HIV (Apr 2013)
National guideline for the management of chancroid; British Association of Sexual Health and HIV (2014)
Towards elimination of HIV transmission, AIDS and HIV-related deaths in the UK; Public Health England (November 2017)
Hi all,Used to quite an active member but have generally come to terms a little with my illness over the past ten months. As a back story I caught herpes off my new partner. He didn't know he had it...r35506
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