STI stands for Sexually Transmitted Infection, and refers to a range of infections that can be passed from person to person during sexual contact.

Most STIs are transmitted through bodily fluids during oral, vaginal or anal sex, including the use of sex toys, but some can be passed on through simple skin-to-skin contact.

It is important to protect yourself from STIs by practicing safe sex. Condoms, femidoms and dental dams are the only methods of contraception that protect you against most STIs and you can find out more about them here.

Some STIs can also be transmitted in other ways, such as sharing injecting drug equipment (i.e. needles), through childbirth and breast feeding.

Most STIs can be treated if caught early enough, but they can cause serious problems if left untreated for a long time. So it is important to get tested if you think you have been at risk.

Click on an STI below to find out more information about the infection, or download Wee Johnny’s Guide to STIs.

To find out more about what to expect when you visit a sexual health clinic, click here.

Chlamydia

Chlamydia is one of the most common STIs and is particularly common among under-25s.

It’s caused by a bacteria and can affect anyone who has ever had unprotected anal, oral or vaginal sex. Using condoms and femidoms is the best way to prevent new infections.

  • 1 in 10 young people in the UK who are sexually active are thought to have chlamydia
  • There are often no signs or symptoms – however some people may experience symptoms including unusual discharge, bleeding between or irregular periods, and lower abdominal pain
  • It is a bacterial infection which can be treated with antibiotics
  • Tests usually involve giving a urine sample or taking a vaginal swab, and can be done 2 weeks after unprotected sex
  • If left untreated, chlamydia can affect fertility in men and women.

Check out the NHS Choices website for more information about chlamydia.

If you would like to know more about STI testing, check our Visiting a Clinic page.

Genital herpes

Genital herpes is a common viral infection. There are two strains of the herpes virus, both of which can cause genital herpes.

  • Causes very sore, painful blisters on the genitals, but can also infect the anal area
  • Highly contagious
  • Treated with antiviral medicines but there is no cure and you may experience future outbreaks when feeling down or poorly - an outbreak in either you, or your partner, does not necessarily mean your partner has been having sex with other people
  • Tests usually involve a health professional examining your genitals and taking a swab of fluid from a blister if present
  • Even if someone with genital herpes has no symptoms, they can pass it on
  • If you have genital herpes and are experiencing an episode, you should avoid having sex from the first tingle or itch until any blisters or ulcers have cleared up.

Check out the NHS Choices website for more information about genital herpes.

If you would like to know more about STI testing, check our Visiting a Clinic page.

Genital warts

Genital warts are small fleshy growths or bumps commonly found around the genital skin or anus.

They are spread by skin-to-skin contact and are the result of a viral skin infection caused by the Human Papilloma Virus (HPV). Using condoms and femidoms is the best way to protect yourself from genital warts.

  • Genital warts are the second most common type of STI in under 25s in the UK, after chlamydia
  • Most people who have an HPV infection will not develop genital warts
  • Genital warts can take months or years to develop after an infection so if they appear on you, or your partner, this does not necessarily mean that your partner has been having sex with other people
  • Treatment will depend on how many warts you have, but will involve either creams or freezing
  • An HPV vaccine is routinely offered to girls aged 11-13 to protect against cervical cancer, and is also available to gay and bisexual men through sexual health clinics
  • Diagnosis involves a health professional examining any growths

Check out the NHS Choices website for more information about genital warts.

If you would like to know more about STI testing, check our Visiting a Clinic page.

Gonorrhoea

Gonorrhoea (sometimes known as ‘the clap’) is one of the most common STIs.

It’s caused by a bacteria and can affect anyone who has ever had unprotected anal, oral or vaginal sex. Using condoms, femidoms and dams is the best way to protect yourself.

  • 1 in 10 men and half of women with gonorrhoea experience no signs or symptoms – though you may experience symptoms including yellow or green discharge, a burning feeling when peeing and lower abdominal pain or tenderness
  • Gonorrhoea is a bacterial infection which, in most cases, can be treated with antibiotics
  • Tests usually involve taking a swab of discharge or giving a urine sample, and can be done 2 weeks after unprotected sex
  • If left untreated, gonorrhoea can affect fertility in men and women

Check out the NHS Choices website for more information about gonorrhoea.

If you would like to know more about STI testing, check our Visiting a Clinic page.

Hepatitis

Hepatitis is a viral infection that can cause damage to the liver.

There are various types of hepatitis, each with differences in terms of transmission and treatment. In Scotland, the most common types are hepatitis B and hepatitis C.

  • Present in blood and bodily fluids
  • Hepatitis B is primarily transmitted during unprotected sex and by sharing injecting equipment
  • Hepatitis C is primarily transmitted through sharing injecting equipment – it is less commonly transmitted during sex
  • Both types can be transmitted in other ways – e.g. through sharing household items like razors and toothbrushes; through tattoos that aren’t done in hygienic settings
  • Often comes with no symptoms, but initial symptoms can be similar to flu
  • Most people will clear (get rid of) hepatitis B naturally, but some will go on to develop chronic infection
  • Around one in five people will clear hepatitis C naturally
  • Chronic hepatitis B can be treated to manage the virus but it cannot be cured – a vaccine is available for people who are at increased risk
  • Effective treatments are available that can cure hepatitis C
  • The only way to tell if you have hepatitis is through a blood test
  • If left untreated, hepatitis can cause serious liver damage, including cirrhosis and liver cancer

Check out the NHS Choices website for more information about hepatitis.

If you would like to know more about STI testing, check our Visiting a Clinic page.

HIV

HIV is a virus that infects the body’s white blood cells and stops the immune system, which fights infection, from functioning properly.

HIV is present in blood and genital fluids and is primarily transmitted during unprotected sex and by sharing injecting equipment.

  • HIV stands for Human Immunodeficiency Virus
  • Can be transmitted during anal and vaginal sex, and, less commonly, through oral sex or sex toys
  • Symptoms vary from person to person – many people will have flu-like symptoms in the weeks after becoming infected
  • Many other common illnesses share these symptoms so the only way to know if you have HIV is to take a test
  • HIV cannot be cured, but treatment can control the virus and allow people living with the condition to live long, healthy lives
  • Treatment reduces the levels of the virus in the blood to the point where it cannot be detected and you cannot pass it on
  • Using condoms and femidoms is the best way to protect yourself and your partner from HIV
  • HIV can be detected in the body four weeks after exposure to the virus - the most common way of testing for HIV involves taking a small sample of blood
  • Pregnant women are offered an HIV test early in their pregnancy – if HIV is diagnosed, treatment can be started that makes it very unlikely that a baby will be born with HIV
  • After a baby is born to a mother living with HIV, the advice is not to breastfeed as there is a small risk of transmission
  • If left untreated, HIV can lead to an AIDS (Acquired Immune Deficiency Syndrome) diagnosis – this is when the immune system is vulnerable to infections that a healthy person could fight off
  • Thanks to advances in treatment, AIDS diagnoses are very rare in Scotland – in 2016 there were just 6 diagnoses

Check out the NHS Choices website for more information about HIV.

If you would like to know more about STI testing, check our Visiting a Clinic page.

Pubic lice

Pubic lice (otherwise known as crabs) are very small, parasitic insects which live on the pubic hair.

They can be passed on during sexual contact, or through other close body contact like sharing towels or bed linen.

  • Symptoms can take a few weeks to appear and include itching, irritation and inflammation -you may be able to see black powder (droppings), brown eggs or the actual lice
  • Diagnosis involves a health professional examining the area to look for the crabs (which can grow to the size of a pin head)
  • Treatment involves using lotion or shampoo.
  • There’s not much you can do to prevent crabs, but they are easily treated and, aside from being incredibly itchy, are completely harmless

Check out the NHS Choices website for more information about pubic lice.

If you would like to know more about STI testing, check our Visiting a Clinic page.

Syphilis

Syphilis is a bacterial STI. It is less common than other STIs, but new cases are on the increase.

The infection can be passed on during unprotected anal, vaginal or oral sex, and using condoms, femidoms or dams is the most effective way to protect yourself.

  • The first symptom is small, painless sores in the genital or anal area called a chancre
  • Symptoms can progress to include a non-itchy rash on the palms or soles of the feet, small skin growths, flu-like symptoms, swollen glands, weight loss and patchy hair loss
  • Diagnosis usually involves an examination, followed by swabs (if there are sores) and a blood test
  • If caught early, it can be treated with an antibiotic injection (often penicillin) or other forms of antibiotics.
  • If left untreated, syphilis can cause serious illness – including damage to the brain, heart and liver

Check out the NHS Choices website for more information about syphilis.

If you would like to know more about STI testing, check our Visiting a Clinic page.

Thrush

Thrush isn’t an STI, but a common yeast infection that affects both men and woman.

  • Symptoms can include thick white discharge, itchiness and irritation, and burning and stinging when having sex or peeing
  • Can be treated easily with creams and tablets that can be bought from a pharmacy or chemist – or through your GP
  • It is usually harmless but can keep coming back, even if treated

Check out the NHS Choices website for more information about thrush.