Sexually Transmitted Infections
This leaflet gives some brief information about sexually transmitted infections and what you are advised to do if you suspect that you have a sexually transmitted infection. This leaflet also gives some information about genitourinary medicine clinics, sometimes called sexual health clinics. For example, how you can find a genitourinary medicine clinic and what you can expect when you go to one. There are separate leaflets that deal with each infection in more detail.
Some brief information about sexually transmitted infections (STIs)
What is an STI?
An STI is an infection that can be passed from person to person when having sex. You can get an STI by having vaginal sex, anal sex, or oral sex. There are several different types of STI.
What are the main STIs?
The ten most common STIs in the UK are anogenital warts, chlamydia, genital herpes, gonorrhoea, human immunodeficiency virus (HIV), hepatitis B, hepatitis C, pubic lice, syphilis and trichomonas. These are briefly described below and separate leaflets give more details for each.
Anogenital warts are small lumps that develop on the genitals and/or around the back passage (anus). They are sometimes just called genital warts. They are caused by a germ (virus) called the human papillomavirus (HPV). However, most people infected with HPV do not develop visible 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. Treatment options include applying chemicals to the warts or freezing the warts to destroy them.
Chlamydia is caused by a germ (bacterium) called Chlamydia trachomatis. It is the most common STI in the UK. Symptoms include a vaginal discharge in women and a discharge from the penis in men. You can be infected with chlamydia for months, even years, without realising it, as it often causes no symptoms. However, even if you have no symptoms, you can still pass on the infection and complications may develop if it is left untreated (such as pelvic infection and infertility in women). A short course of an antibiotic medicine clears chlamydia in most cases.
Genital herpes is caused by the herpes simplex virus. Once you catch this virus it stays with you for life but lies dormant without causing symptoms for most of the time. In fact, many people who are infected with this virus never have symptoms. If symptoms occur, they can range from a mild soreness to many painful blisters on the vulva or penis and surrounding area. A first episode of symptoms can last 2-3 weeks but may be shorter. Recurrent episodes of symptoms then develop in some cases from time to time but are usually less severe than the first episode. (It is similar to having cold sores but on the genitals from time to time.) Antiviral medication can ease symptoms when they develop.
Gonorrhoea is caused by a bacterium called Neisseria gonorrhoeae. Symptoms include a vaginal discharge in women and a discharge from the penis in men. Again, some people infected with gonorrhoea do not develop symptoms. However, even if you have no symptoms, you can still pass on the infection and complications may develop if it is left untreated (such as pelvic infection and infertility in women). A short course of an antibiotic clears gonorrhoea in most cases.
Human immunodeficiency virus (HIV) is most commonly passed on by sexual contact. HIV attacks cells of the immune system. Over time (usually several years) the immune system weakens so that you cannot defend your body against various bacteria, viruses and other germs. This is when acquired immunodeficiency syndrome (AIDS) develops. Many infections and conditions can develop if you have AIDS. Treatment with antiretroviral medicines can reduce the viral load of HIV and allow your immune system to work effectively. However, treatment does not clear the virus from the body. Therefore, if you are infected with HIV, you will need monitoring for the rest of your life and treatment is long-term.
Hepatitis B is a virus that primarily attacks the liver. The virus is mainly passed on by sexual contact, sharing contaminated needles to inject street drugs, or from an infected mother to her baby. The hepatitis B virus can cause a short-term (acute) infection, which may or may not cause symptoms. Following an acute infection, some people develop a persistent infection called chronic hepatitis B. Many people with chronic hepatitis B remain well but can still pass on the virus to others (as they are carriers). Some develop serious liver problems. If needed, antiviral medication may prevent or reduce the severity of liver inflammation and liver damage.
Hepatitis C is is a virus that primarily attacks the liver. Most cases occur in people who share needles contaminated with traces of infected blood, in order to inject street drugs. There is a small risk that an infected person can pass on the virus whilst having sex. Some people clear the infection naturally. Some people with persistent (chronic) infection remain free of symptoms but some have symptoms. After many years of infection, some people develop a severe scarring of the liver (cirrhosis) and some develop liver cancer. Treatment is difficult but it can clear the infection in up to half of cases.
Pubic lice (often called crabs) are tiny insects about 1-2 mm long (smaller than a match head). They lay eggs which hatch into lice after seven days. Pubic lice attach strongly to hairs and do not wash or brush off with normal cleaning. Pubic lice are passed on by close bodily contact, especially when having sex. The main symptom is itch, usually in the pubic hair area. However, you may not have any symptoms but may still pass on the lice to others. Treatment with a lotion or cream usually clears the lice.
Syphilis is caused by a bacterium called Treponema pallidum. If it is not treated, it can spread in the bloodstream from the genital region to cause various symptoms and problems in different parts of the body over many years. A short course of antibiotics usually clears syphilis infection.
Trichomonas is a protozoan, which is a tiny germ similar to a bacterium. It can cause an infection that is not normally serious but symptoms can be unpleasant. Symptoms include a vaginal discharge in women and a discharge from the penis in men. Some people infected with trichomonas do not have symptoms but can still pass on the infection. A course of antibiotics usually clears trichomonas infection.
There are some other STIs that are uncommon in the UK - for example, donovanosis and chancroid.
Other conditions that are sometimes thought of as sexually transmitted infections (STIs)
Scabies is a common skin rash that is caused by a tiny insect (mite). It is usually very itchy. You need close skin-to-skin contact with an infected person to catch scabies. Most cases are probably caught from holding hands with an infected person. However, sleeping in the same bed and sexual contact are other common ways of passing on the mite which is why some people regard scabies as an STI.
Molluscum contagiosum is a common skin rash that is caused by a germ (virus). It is passed on by skin-to-skin contact. The rash consists of small lumps which are pearly-white or slightly pink. Each lump (molluscum) looks like a small wart and is round, firm and about 1-5 mm across. Sometimes the virus is passed on during the close contact of having sex. So, some people regard molluscum contagiosum as an STI. If it is passed on whilst having sex then the first mollusca to appear tend to be on the skin around the penis or vagina.
However, many cases of molluscum contagiosum are not caused by a sexual contact but by simply touching other affected people. It is a common condition that is seen both in adults and in children.
What are urethritis, balanitis, pelvic inflammatory disease and vulvitis?
These terms describe the site of a problem rather than a particular cause of the problem.
Urethritis means inflammation of the urethra. The urethra is the tube that passes out urine from the bladder. If you have urethritis you may develop a burning sensation when you pass urine and men may have a discharge from the end of the penis. Urethritis is usually caused by a sexually transmitted infection (STI) but not always. For example, it can be caused by chlamydia or gonorrhoea (see above) but can also be caused by injury and some other causes.
Balanitis means inflammation of the tip of the penis. Balanitis is sometimes caused by an STI. However, it is most commonly caused by non-sexually transmitted infections and skin conditions. Balanitis is common in young children, due to non-sexually transmitted infections.
Pelvic inflammatory disease (PID)
PID is an infection of the womb (uterus). Germs (bacteria) that cause the infection usually travel into the uterus from the vagina or neck of the uterus (cervix). An STI is a common cause of PID. Most cases are caused by chlamydia or gonorrhoea. However, some cases are not due to an STI. Symptoms of PID include pain in the lower tummy (abdomen), high temperature (fever), abnormal vaginal bleeding and a vaginal discharge. Possible complications include infertility, persistent pain and an increased risk of an ectopic pregnancy if you become pregnant.
Vulvitis means inflammation of the vulva. (The vulva is the skin just outside the vagina.) There are various causes of vulvitis, including some STIs.
Conditions that are not sexually transmitted infections (STIs)
The genitals (vagina and vulva in women, penis in men) can be affected by various other conditions. Some people are confused as to what is and what is not caused by an STI. For example, the following are not usually due to an STI:
- Thrush is an infection caused by a yeast germ called Candida spp. Small numbers of Candida spp. commonly live on the skin and around the vaginal area. These are usually harmless. However, when conditions are good for Candida spp., they multiply and may invade the vagina and cause symptoms such as a vaginal discharge.
- Bladder infection (cystitis).
- Bacterial vaginosis is a common condition of the vagina. It is caused by an overgrowth of various germs (bacteria) that are normally found in the vagina. It is the most common cause of a vaginal discharge.
What are the symptoms of a sexually transmitted infection (STI)?
Symptoms of each STI can vary, from local symptoms affecting the genitals, to symptoms that affect various other parts of the body. The following is not a full list of all possible symptoms. However, these are the common symptoms to look out for:
- A vaginal discharge.
- Abnormal vaginal bleeding.
- A discharge from the penis.
- A sore, ulcer, rash, or lump that appears on the penis or around the vagina, vulva or back passage (anus).
- Pain when you have sex.
- Pain when you pass urine (although the common reason for this is a urine infection and not an STI).
- Swelling of the glands in your groin.
But remember, in many cases of STI, no symptoms may develop. However, you can still pass on the infection to others even if you have no symptoms. Therefore, if you think that you may have an STI, it is best to get it checked out.
What should I do if I suspect that I have a sexually transmitted infection (STI)?
If you have a symptom that you think is due to an STI, or if you have no symptoms but are worried you have caught an STI then you should see a health professional. You can:
- See your own GP. Your GP can give advice and may examine you. However, if your GP suspects that you may have an STI, he or she is likely to refer you to a GUM clinic. Some GPs may do tests and manage the situation without a referral to a GUM clinic; OR
- Go to a GUM clinic directly. You do not need a referral from your GP to go to a GUM clinic.
Until you are checked out, and treated if necessary, you should not have sex. This is to prevent you passing on any infection.
What are genitourinary medicine clinics?
GUM clinics are special clinics that help people who have, or may have, an STI or certain other problems with their genitals or urinary system. See separate leaflet called Tests for Sexually Transmitted Infections for more details.
Depending on the initial assessment and examination, the doctor may advise on some tests and ask for your consent to do the tests. Tests for sexually transmitted infections (STIs) may include a urine test, swabs or blood tests. (A swab is a small ball of cotton wool on the end of a thin stick, used for collecting samples.) See separate leaflet called Tests for Sexually Transmitted Infections for more details.
Sometimes a doctor will be able to diagnose a sexually transmitted infection (STI) from the examination. Sometimes you will need to wait for the results of some tests. Some test results can be available quickly - during your time in the clinic. For other tests it takes a few days for the results to come back from the laboratory. You may be given an appointment to come back for the results of tests, or in some situations you may be able to phone for the results.
Advice about sexual partners
If you are diagnosed with a sexually transmitted infection (STI) then the clinic will encourage you to tell any current or recent sexual partners that you have an infection. You are not obliged to do this or to give out any information about other people. However, it is best that any recent sexual partners should know that they might also be infected. They should be offered testing and treatment if necessary, to prevent the infection being spread any further. This telling of sexual partners is sometimes called contact tracing. If you prefer, clinics can contact people anonymously if you do not wish to tell them yourself. You should be aware that recklessly exposing a sexual partner to the risk of infection is against the law.
The treatment that you will be offered depends on what sexually transmitted infection (STI) is found. For example, a short course of antibiotics can usually clear away chlamydia, gonorrhoea, syphilis and trichomonas. A cream or lotion can clear pubic lice and scabies. Topical treatments can usually clear most anogenital warts. Treatments for genital herpes, hepatitis B, hepatitis C and HIV are more involved and complex. You will be given advice about what treatment options you have and given time to ask questions.
If you are prescribed antibiotics then it is important to finish the full course of tablets, or else the infection may not be fully cleared. If you develop side-effects then seek advice from the GUM clinic or from your GP as to what to do. Do not simply stop taking the medication. For some infections you will be asked to return after a course of treatment to check that the infection has gone.
Do not have sex again until the time advised by the clinic. Depending on the infection, this may be for a certain length of time after treatment has finished or it may be until you are given the all clear from a repeat test. The aim is to prevent you from passing on the infection to others.
Advice from a sexual health adviser
Most clinics will have a sexual health adviser. You are likely to be seen by the adviser in addition to being seen by a doctor or nurse. A sexual health adviser is specially trained and can:
- Tell you more about STIs and how to avoid catching them in future. For example, the risk of infection increases with the number of changes of sexual partner. Wearing a condom during sex helps to prevent against STIs.
- Give you tips on how to cope with any current symptoms.
- Offer you free condoms which can help to prevent STIs.
- Give advice about what to tell your sexual partner or previous partners.
- Help you with contacting previous sexual partners who should be tested or treated. For example, you may be given a card with a number on it, plus a printed message advising the person who is given the card to visit the clinic and to bring the card along. This helps to match them with your notes.
In addition to diagnosing and treating STIs, if needed, a GUM clinic can also usually:
- Do a pregnancy test.
- Arrange counselling if you are pregnant and are not sure what to do.
- Arrange counselling about the decision to have an HIV test.
- Provide advice about contraception.
- Provide emergency contraception.
- Do a cervical smear test on women if one is due.
- Diagnose and treat some other conditions of the genitals that are not sexually transmitted. For example, a urine infection, thrush and some skin conditions affecting the genital area.
Further help & information
23-28 Penn Street, London, N1 5DL
Further reading & references
- Sexually transmitted infections (STIs): surveillance, data, screening and management; Public Health England, 2016
- National guideline for the management of chancroid; British Association of Sexual Health and HIV (2014)
- Sexually Transmitted Infections in Primary Care; Royal College of General Practitioners and British Association for Sexual Health and HIV (Apr 2013)
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Tim Kenny
Dr Laurence Knott
Dr Helen Huins