What Are STIs?

Learn more about STIs, how they’re treated and how to prevent catching or spreading them…

STIs are sexually transmitted infections, passed on through unprotected vaginal, anal or oral sex. STIs are a lot more common than you might thing – in fact, many people who have an STI are completely unaware because they may not have any symptoms. That’s why it’s so important to get tested regularly and use condoms to keep yourself and others safe.

Condoms & STIs

Condoms are not just for preventing pregnancy. When used correctly, condoms are very effective at protecting you and your partner from catching or sharing most STIs. Warts and herpes are spread by skin to skin contact and can still be passed on even when condoms are used.

All other birth control, such as the combined pill or IUD, will not protect from catching an STI. That’s why it’s important to use condoms in combination with your usual birth control.

Symptoms Of STIs

The symptoms can include:

  • Unusual discharge from the penis, vagina or anus
  • Pain when peeing
  • A rash
  • Itchy genitals or anus
  • Blisters or sores around your genitals or anus
  • Warts around your genital area or anus
  • Lumps or skin growths around the genitals or anus
  • Unusual vaginal bleeding

What Are The Types Of STIs?

There are many kinds of sexually transmitted infections. STIs are common and can lead to serious health problems if left untreated. The good news is that getting tested for STIs is easy and straightforward – and most can be treated fairly easily, often with a simple course of antibiotics. Types of STI are:


Chlamydia is one of the most common sexually transmitted infections in the UK. It’s caused by a bacterial infection and often doesn’t have any symptoms so many people don’t even know they have it.

Find out more about chlamydia here.


Also caused by a bacterial infection, gonorrhoea is sometimes also known as “the clap”. Typical symptoms include a thick green or yellow discharge from vagina or penis or pain when peeing. Women may experience bleeding between periods. However, around 1 in 10 men and almost half of all women have no symptoms at all.

Pubic Lice

Also known as “crabs”. Pubic lice are tiny insects that live on coarse human hair (such as pubic hair) and can make your life an itchy hell, especially at night. Other symptoms include black powder in your underwear or small spots of blood on your thighs or lower abdomen which are caused by lice bites.


Another STI caused by a pesky parasite. Trichomoniasis can cause unpleasant, fishy-smelling discharge in women and pain or discomfort when peeing or having sex. For men, it can cause pain when peeing or soreness and swelling around the head of the penis. Almost half of all people with Trichomoniasis don’t develop any symptoms at all but they can still pass it on.


Sounds as unpleasant as it is. Tiny mites lay eggs under the skin, causing a rash and an intense itch, especially at night. The rash can appear anywhere on the body but usually starts between the fingers before spreading across the body. It’s very infectious, meaning everyone in your house will have to be treated at the same time, as well as anyone you have had sexual contact with in the past 8 weeks. Thankfully, it can be treated with a lotion or cream to be applied to the whole body. 


Symptoms can include small, painless sores or ulcers around the genitals or anus, a blotchy red rash on the palms of the hands or soles of the feet and white patches in the mouth. Left untreated for years, syphilis can cause serious health problems so it’s important to get tested if you think you might have it. Treating and curing syphilis can be done with a simple course of antibiotics but you can catch it more than once so it’s important to practice safe sex to protect yourself and others.

Genital Herpes

Symptoms of herpes can be small blisters that burst to leave red, open sores on the genitals, anus, thighs or bottom. It might also hurt to pee and women may experience unusual discharge. You can be tested for herpes with a simple swab. There’s no cure for herpes – symptoms will go away by themselves but they can come back. You may be given a cream to help with the discomfort or an antiviral medicine to prevent symptoms from getting worse.

Genital Warts

This STI usually appears as small, painless growths or lumps on the genitals. Depending on how the warts look and where they are, you can be treated with:

  • Creams or liquids to be applied to the affected area
  • Freezing of the warts which can be painful. This treatment often needs to be repeated several times.
  • Surgery to cut away, burn or remove the warts with a laser. 

HPV (Human Papillomavirus)

This is a common group of more than 100 viruses that affects the skin. These viruses often don’t cause any problems but can sometimes cause genital warts or cancer. Women in England are tested for HPV at their smear from the ages of 25-64 to help protect against cervical cancer.


HIV is a sexually transmitted virus that, if left untreated, can lead to AIDS. There is no cure for HIV or AIDS but there are effective treatments for HIV which enable people to live long and healthy lives. People with HIV may have a short flu-like illness shortly after getting the virus but won’t notice symptoms until after a few years. They may notice weight loss, thrush in the mouth, swollen glands in the groin, neck or arm and feeling very tired.

How To Get Checked For An STI

Getting tested for sexually transmitted infections is usually painless and simple. You can get help, advice and treatment by:

  • Visiting your local sexual health clinic. To find your nearest centre, click here.
  • Making an appointment with your GP.
  • Checking with your local pharmacy. Some can test for chlamydia.
  • Ordering self-test kits online, depending on where you live. These are free and confidential. Check here to find out if self-test kits are available in your area.
  • Calling the National Sexual Health line on 0300 123 7123. Every call is handled with the strictest confidence.

Related Posts

Download the App

Hidden strength the go – to, advice + support portal for 13 – 24 year olds designed to provide accessible and immediate support and chat-based therapy from qualified therapists to any young people who may be struggling with their mental wellbeing, completely for free.