An Introduction to Sexually Transmitted Diseases

What are Sexually Transmitted Diseases (STDs)?

Sexually Transmitted Diseases (STDs) are diseases that can be transmitted through body contact during sex. They are caused by viruses, bacteria and parasites. They can also be known as Sexually Transmitted Infections (STIs) or by their old name Venereal Diseases (VD). There are at least 25 different sexually transmitted diseases. What they all have in common is that they can be spread by sexual contact, including vagina, anal and oral sex. The diseases discussed on this page are not a comprehensive list of all STDs, simply the most common ones. We also have pages with information on the transmission of HIV.

How do you know that you have an STD?

Anyone who is sexually active can be at risk from STDs. Some STDs can have symptoms, such as genital discharge, pain when urinating and genital swelling and inflammation. Many STDs, such as Chlamydia, can frequently be symptomless. This is why it is advisable to have a sexual health check-up, to screen for STDs, if you think you have been at risk. It can sometimes take a long time for STDs to display any symptoms, and you can pass on any infections during this time, further demonstrating the need to be tested and treated. If you are in a relationship, and are diagnosed with an STD, it does not necessarily mean that your partner has been unfaithful. Symptoms of STDs can present themselves months after infection.

How can you prevent yourself from getting STDs?

You can minimise the risk from STDs by having protected sex with condoms and getting yourself and your partner(s) tested. The more partners you have the greater the risk of acquiring an STD. Other ways to reduce the risk include using dental dams and condoms during oral sex, cleaning sex toys after use, cleaning your hands after having sex, and improving genital hygiene routines.

Why is it important to know if you have an STD?

Many STDs are very infectious and can cause long-term or permanent damage, including infertility if left untreated. Many STDs can be easily passed onto sexual partners, and some STDs can be passed from a mother to her unborn child too. STDs can also aid the transmission of HIV.

A Guide to STDs

Bacterial Vaginosis (BV) is not strictly an STD as it is not transmitted via sexual intercourse. However, it can be exacerbated by sex and is more frequently found in sexually active women than those who have never had intercourse. It is caused by an imbalance in the normal healthy bacteria found in the vagina and although it is relatively harmless and may pass unnoticed, it can sometimes produce an abundance of unpleasant fishy smelling discharge. Whilst there is no clear explanation as to why BV occurs, there have been suggestions that the alkaline nature of semen could be one cause, as it may upset the acidic nature of the vaginal bacteria. Another cause can be the use of an intrauterine contraceptive device (coil). A woman cannot pass BV to a man, but it is important she receives treatment as BV can occasionally travel up into the uterus and fallopian tubes and cause a more serious infection. Treatment for BV consists of applying a cream to the vagina or taking antibiotics.

Balanitis is often referred to as a symptom of infection, and not necessarily an infection in its own right. It is not strictly an STD, more a consequence of sexual activity. It only affects men and usually presents itself as an inflammation of the head of the penis, and is more common in men who are not circumcised. It can be caused through poor hygiene, irritation due to condoms and spermicides, using perfumed toiletries and by having thrush. It can be prevented through not using certain toiletries and by washing under the foreskin. Treatment can consist of creams to reduce inflammation and antibiotics if necessary.

Chlamydia is the most common treatable bacterial STD. It can cause serious problems later in life if it is not treated. Chlamydia infects the cervix in women. The urethra, rectum and eyes can be infected in both sexes. Symptoms of infection may show up at anytime. Often this is between 1 to 3 weeks after exposure. However, symptoms may not emerge until a long way down the line. Find out more about chlamydia.

Crabs or Pubic Lice are small, crab shaped parasites that live on hair and which draw blood. They live predominantly on pubic hair, but can also be found in hair in the armpits, on the body and even in facial hair such as eyebrows. They can live away from the body too, and therefore can be found in clothes, bedding and towels. You can have crabs and not know about it, but after 2 to 3 weeks, you would expect to experience some itching. Crabs are mainly passed on through body contact during sex, but they can also be passed on through sharing clothes, towels or bedding with someone who has them. There is no effective way to prevent yourself becoming infected, though you can prevent others becoming infected by washing clothes and bedding on a hot wash. Lotions can be bought from pharmacies and applied to the body to kill off the parasites. Shaving off pubic hair will not necessarily get rid of crabs.

Epididymitis refers to inflammation of the epididymitis, a tube system above the testicles where sperm are stored. It is not always the result of an STD, but if it is, it is usually due to the presence of Chlamydia or Gonorrhoea. Symptoms will present themselves in the form of swollen and painful testicles and scrotum. The best way of preventing it is to use condoms during sex, as this is the most effective way to prevent Chlamydia and Gonorrhoea. Epididymitis itself cannot be passed on, though any other infections that may have caused epididymitis can be passed on (see Chlamydia and Gonorrhoea sections). Treatment usually involves treating the underlying infection with antibiotics.

Genital herpes is caused by the herpes simplex virus. The virus can affect the mouth, the genital area, the skin around the anus and the fingers. Once the first outbreak of herpes is over, the virus hides away in the nerve fibres, where it remains totally undetected and causes no symptoms. Symptoms of the first infection usually appear one to 26 days after exposure and last two to three weeks. Both men and women may have one or more symptoms, including an itching or tingling sensation in the genital or anal area, small fluid-filled blisters that can burst and leave small sores which can be very painful, pain when passing urine, if it passes over any of the open sores and a flu-like illness, backache, headache, swollen glands or fever. Find out more about genital herpes.

Genital warts are small fleshy growths which may appear anywhere on a man or woman's genital area. They are caused by a virus called the Human Papilloma Virus (HPV). Warts can grow on the genitals, or on different parts of the body, such as the hands. After you have been infected with the genital wart virus it usually takes between 1 and 3 months for warts to appear on your genitals. You or your partner may notice pinkish/white small lumps or larger cauliflower-shaped lumps on the genital area. Warts can appear around the vulva, the penis, the scrotum or the anus. They may occur singly or in groups. They may itch, but are usually painless. Often there are no other symptoms, and the warts may be difficult to see. If a woman has warts on her cervix, this may cause slight bleeding or, very rarely, an unusual coloured vaginal discharge. Find out more about genital warts.

Gonorrhoea is a bacterial infection. It is sexually transmitted and can infect the cervix, urethra, rectum, anus and throat. Symptoms of infection may show up at anytime between 1 and 14 days after exposure. It is possible to be infected with gonorrhoea and have no symptoms. Men are far more likely to notice symptoms than women. Find out more about gonorrhoea.

Gut Infections can be passed on during sex. Two of the most common infections are Amoebiasis and Giardiasis. They are bacterial infections, and when they reach your gut they can cause diarrhoea and stomach pains. Gut infections can be passed on when having sex with someone who is infected, especially during activities that involve contact with faeces, such as rimming and anal sex. Infection can be prevented through using condoms, dental dams or latex gloves. Sex toys should be thoroughly cleaned after use and hands washed after any contact with faeces. Anti-diarrhoea treatments should be enough to treat most infections, but antibiotics can also be used.

Hepatitis causes the liver to become inflamed. There are various different types of hepatitis, the most common being hepatitis A, B and C. Each of these viruses acts differently. Hepatitis can be caused by alcohol and some drugs, but usually it is the result of a viral infection. Find out more about hepatitis.

Molluscum is a skin disease caused by the Molluscum Contagiosum Virus. It appears as small bumps on the skin, and can last from a couple of weeks to a few years. Molluscum cause small, pearl-shaped bumps the size of a freckle on the thighs, buttocks, genitalia and sometimes the face. They are passed on through body contact during sex and through skin-to-skin contact. Transmission can help to be prevented by using condoms, by avoiding skin-to-skin contact with someone who is infected and by not having sex until they have been treated. In most cases molluscum do not need treatment and will disappear over time. However, they can be frozen off or a chemical can be painted on.

Non-Specific Urethritis (NSU) is an inflammation of a man's urethra. This inflammation can be caused by several different types of infection, the most common being Chlamydia. NSU may be experienced months or even in some cases years into a relationship. The symptoms of NSU may include pain or a burning sensation when passing urine, a white/cloudy fluid from the tip of the penis that may be more noticeable first thing in the morning, feeling that you need to pass urine frequently. Often there may be no symptoms, but this does not mean that you cannot pass the infection on to your partner(s). Find out more about NSU.

Scabies is caused by a parasitic mite that can get under the skin and cause itching. The mites are very small and cannot be seen, and many people do not now they have them. They can cause itching, and this can start between 2 to 6 weeks after infection. Signs of infection can be red lines under the skin of the hands, buttocks and genitals. The most common way of becoming infected is through body contact during sex, though it is also possible to be infected through sharing towels and clothes with someone who is infected. This route however is uncommon. There is no effective way to prevent yourself becoming infected, though you can prevent others becoming infected by washing clothes and bedding on a hot wash. Lotions can be bought from pharmacies and applied to the body to kill off the parasites.

Syphilis is not a common infection in the UK but it is more common in some other countries. It is a bacterial infection. It is usually sexually transmitted, but may also be passed from an infected mother to her unborn child. The signs and symptoms of syphilis are the same in both men and women. They can be difficult to recognise and may take up to 3 months to show after having sexual contact with an infected person. Syphilis has several stages. The primary and secondary stages are very infectious. Find out more about syphilis.

Thrush, also known as candiasis, is a yeast which lives on the skin and is normally kept in check by harmless bacteria. If this yeast multiplies however, it can cause itching, swelling, soreness and discharge in both men and women. Women may experience a thick white discharge and pain when passing urine. Men may experience the same discharge in the penis and difficulty pulling back the foreskin. Thrush can be passed on when having sex with someone who is infected, but also if you wear too tight nylon or lycra clothes or if you are taking certain antibiotics. Sometimes the cause may be unclear however. Transmission can be prevented by using condoms during sex and by men washing underneath their foreskin. Treatment for thrush involves taking or applying anti fungal treatments. Thrush can reoccur, especially in women.

TrichomonasVaginosis, also known as Trich is caused by a parasite that is found in women's vagina's and men's urethra's. Often there are not any symptoms. If symptoms are present, they can include pain when urinating and discharge in men and discharge, soreness when having sex and when urinating and inflammation of the vulva in women. Transmission normally occurs through having oral, anal or vaginal sex with an infected person. Treatment consists of taking antibiotics, and the infection should not reoccur.

The information given on this page is not intended to be a substitute for any professional medical advice. Please consult with your healthcare provider if you have any concerns.

Avert.org has a number of other STD-related pages.