When it comes to sexually transmitted diseases, it’s typically an itching or a burning sensation in your privates that makes you think something’s up.
But, it’s not just our genitals we should be worried about. It turns out there are far more unexpected places on our bodies that symptoms can manifest.
And with 402,000 new STI diagnoses in 2025 alone, it seems some of us may need a refresher course in some of the less obvious signs we might need to go to a sexual health clinic.
‘STIs don’t always follow the textbook pattern people expect,’ superintendent pharmacist at Chemist Click, Abbas Kanani, says.
‘It can affect different parts of the body depending on the type of infection and how it has been transmitted, and it shouldn’t automatically be ruled out as having nothing to do with your sexual health.’
The palms of your hands
A rash on the palms of your hands can actually be a later symptom of syphilis, and it can sometimes spread all over your body. This can develop if the STI has been left untreated.
‘Syphilis is one of those infections that can present in ways people simply would not associate with an STI,’ pharmacist Thorrun Govind tells Metro.
‘Later symptoms can include a rash on the palms of the hands which isn’t usually itchy, but it can be mistaken for a number of more familiar skin conditions like eczema, psoriasis or an allergic reaction.’
What’s challenging is this rash can look quite different from person to person. While Thorrun explains you cannot catch syphilis from hand-to-hand touching, you could catch it from touching an infected fluid-filled sore called a chancre.
The soles of your feet
The soles can also be affected by the characteristic rash seen during secondary syphilis. Again, the rash may spread across the body and can be subtle enough to go unnoticed.
‘A rash on the feet is easy to put down to something like athlete’s foot or irritation from footwear,’ Abbas explains. ‘But if you notice an unusual rash on both the palms and soles, particularly alongside other unexplained symptoms, it’s worth getting it checked rather than assuming it’s simply a skin problem.’
If you have a rash like this which also coincides with swollen glands, tiredness and unprotected sex, you’ll want to get yourself down to clinic for an STI test.
The eyes
Not even our eyeballs are safe when it comes to symptoms from sexually transmitted diseases.
And, this time it’s gonorrhoea that’s the likely culprit. ‘Gonorrhoea can reach the eye if infectious genital fluid is transferred there by the hands,’ Thorrun explains.
This can cause redness, pain and discharge, and Thorrun adds it can lead to a serious condition called gonococcal conjunctivitis, which requires urgent medical attention to prevent permanent eye damage.
Untreated syphilis can also affect the eyes and cause symptoms such as eye pain, redness and changes in vision.
The throat
Yes, we just gulped, too. But it’s not difficult to realise why a bad throat could be a symptom of an STI.
‘The throat can be exposed to sexually transmitted diseases through oral sex,’ Thorrun explains. ‘Infections such as gonorrhoea, chlamydia, syphilis, herpes and HPV can all affect the throat.’
Superintendent pharmacist Abbas admits that a sore throat is much more likely to be caused by a common respiratory infection than an STI, but says sexual contact can expose the throat to certain infections.’
The joints
This one is much easier to misdiagnose, because some STIs can spread to the joints.
In rare instances, gonorrhoea can spread to the bloodstream and joints, and other STIs can prompt a case of reactive arthritis.
Symptoms can include painful, stiff or swollen joints. ‘Unexplained joint pain isn’t something most people would immediately associate with an STI,’ says Abbas.
‘But, if joint symptoms develop alongside a rash, eye problems, urinary symptoms or other signs of infection, it’s worth seeking medical advice.’
The mouth and lips
‘A painless mouth ulcer or sore is very common and usually has nothing to do with an STI,’ Abbas explains. But, the mouth and lips are a very vulnerable spot for sexually transmitted diseases from oral sex.
‘The risk can be higher if there are cuts, sores or broken skin in or around the mouth, because this can provide an easier route for infection,’ Thorrun adds.
For example, syphilis can cause painless sores in areas including the mouth and lips, meaning an infection can sometimes be present without obvious genital symptoms.
‘A persistent or unusual sore, particularly after sexual contact with a new partner, shouldn’t simply be ignored,’ Abbas says. ‘Syphilis sores can be painless, which means people may not recognise them as a sign of infection.’
The anus and rectum
This might be far less surprising, but it’s worth an honourable mention. It’s not just the penis and the vagina that can be affected downstairs, but the anus and rectum, too.
Gonorrhoea and chlamydia can infect the rectum and can cause symptoms like discharge, soreness, itching, bleeding or pain when passing poo – although many infections also cause no symptoms.
‘People can feel embarrassed talking about symptoms affecting the anus, but they’re important symptoms to mention,’ Abbas says.
‘Some infections in this area cause no noticeable symptoms at all, so testing is particularly important following unprotected anal sex or if you’ve been told a partner has an STI.’
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