We typically think of a sexually transmitted infection (STI) as something that affects the genitals, whether it's chlamydia or herpes.
But how much do you know about how they can affect other body parts too, like the mouth, eyes, and skin (and other more unexpected areas)?
Here, Dr Neel Patel explains what non-genital STIs are and why we need to be more aware of them, the parts of the body they can affect, and what to do if you think you may have contracted one.
What are non-genital STIs?
"As well as STIs affecting the genitals, it’s possible for STIs to enter through either the skin or mucous membranes and infect other parts of the body. These are known as non-genital STIs," explains Dr Patel, of Lloyds Pharmacy Online Doctor.
"Chlamydia, gonorrhoea, syphilis, herpes, HPV, HIV, scabies and trichomoniasis can all be contracted through areas other than the genitals."
What parts of the body can be affected by non-genital STIs?
Dr Patel say non-genital STIs may affect areas including your:
"For example, if semen were to accidentally get into the eyes, you could contract chlamydia in the eye, resulting in symptoms similar to conjunctivitis," Dr Patel explains.
"Similarly, syphilis can be spread via skin-to-skin contact with somebody who has syphilis, and scabies can be caught through sharing towels, bedding or clothing."
He also points out you can catch both a genital and non-genital STI at the same time, affecting more than one area of the body. "For example, if you were to have oral and vaginal sex with someone who has chlamydia, the STI could infect both your throat and genitals."
How are non-genital STIs transmitted?
Expanding on the above, Dr Patel adds: "These types of STIs are transmitted through contact with another individual’s infected genitals, anus, semen or vaginal or cervical fluids. The infection may even be passed on through contaminated body parts or items, such as a sex toy."
Symptoms of non-genital STIs
"Both genital and non-genital STIs can often be symptomless. For this reason, it’s really important to get tested. The only way to know you have an STI is by taking an STI test," says the expert. Generally, you can get a free STI test at a sexual health or GUM clinic, or through a paid online service.
To find out more about STI symptoms generally, see the NHS website.
Preventing non-genital STIs
Primarily, non-genital STIs can be avoided by you and your partner having regular STI tests and practising safe sex.
"You should also always avoid having sex with anyone who has any potential symptoms of an STI. This may include genital sores, a rash or unusual discharge," says Dr Patel.
"For oral sex, a condom or dental dam (a rectangular piece of latex that covers the genitals or anus) can be used to stop STIs being transmitted through the mouth.
"Thoroughly washing your hands after sex can also help to prevent the spread of non-genital STIs.
"STIs like Hepatitis A, Hepatitis B and HPV can also be prevented through vaccines. And the medication, PrEP (Pre-Exposure Prophylaxis) can reduce the risk of contracting HIV."
Treating non-genital STIs
"STI treatments work to get rid of the STI whether you have a genital or non-genital STI. Based on your consultation, the clinician will take into account the types of sex you have had and prescribe the right treatment for you," says Dr Patel.
Testing non-genital STIs
"Testing for non-genital STIs is typically carried out by sampling the area that may have been infected, as well as traditional urine and blood tests. For example, if you are experiencing symptoms that affect your eyes, a healthcare professional may swab your eyes and send this sample for testing," adds Dr Patel.
If you are worried about having a non-genital STI, speak to your healthcare provider.
Read more: Six STIs that could impact fertility (Yahoo Life UK, 5-min read)
I got herpes after a man pressured me into unprotected sex—I thought my life was over (Yahoo Life UK, 9-min read)
Sexual health doctor reveals the six questions you should ask a new partner(Yahoo Life UK, 6-min read)
The health benefits of using a vibrator regularly (Yahoo Life UK, 7-min read)
Watch: Free condoms: Why do some EU members provide them and others do not?