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Tell-tale signs

The symptoms of each sexually transmitted infection (STI) aren’t the same for everyone, but this page gives a rough guide to how infections often show themselves. However, trying to diagnose yourself isn’t a good idea and all STIs (except scabies, crabs and threadworm) need to be treated by a doctor or clinic.

Some of these symptoms can be caused by other common infections, like colds or flu. You can have any of the infections below and not notice any symptoms.

Health advisers in clinics can answer questions about infections, their signs and symptoms over the phone or in person.


  • discharge from cock: gonorrhoea, NSU, chlamydia, Mgen
  • pain when pissing: gonorrhoea, NSU, chlamydia, Mgen
  • sore or blister on cock: herpes, syphilis, LGV
  • itching in or on cock: herpes, thrush
  • small growths on cock: warts, molluscum


  • sore or blister in or around arse: herpes, syphilis, LGV
  • growths in or around arse: warts, molluscum, syphilis
  • discharge from arse: gonorrhoea, chlamydia, herpes, LGV
  • pain or inflammation in arse or when shitting: gonorrhoea, chlamydia, thrush, LGV, herpes
  • itching in or around arse: herpes, thrush, threadworm


  • sore or blister in or around mouth or throat: herpes, syphilis
  • sore throat: gonorrhoea

Rest of body

  • rash: syphilis, scabies, crabs, HIV
  • swollen glands: syphilis, HIV, LGV, herpes
  • pain in balls: chlamydia
  • pain in stomach: hepatitis, gut infections
  • itching on skin: scabies, crabs, hepatitis
  • growths on skin: warts, molluscum
  • diarrhoea: gut infections, hepatitis, HIV
  • losing a lot of weight: gut infections, hepatitis, HIV
  • aches/flu-like illness/fever: hepatitis, herpes, syphilis, HIV, LGV
  • skin or whites of eyes turn yellow: hepatitis
  • pale shit or dark piss: hepatitis
  • extreme tiredness: hepatitis, HIV
  • white ‘threads’ in shit: threadworm
  • grey or white patches in mouth: syphilis, thrush

Last review: 5/11/2018
Next review: 5/11/2021