Urinary & Sexual Health

STI Symptoms, Testing & Online Doctor Help in the UK

7 min readLast reviewed 24 April 2026

Educational information — not medical advice.

This article was prepared by the OnlineDoctor24 editorial team and reviewed for factual accuracy against UK clinical guidance (NHS and NICE). It is not written by a doctor and does not replace personal medical advice. For symptoms specific to you, book an online doctor consultation.

Key points

  • Many STIs cause no symptoms — testing is the only way to know.
  • Free NHS sexual health clinics offer testing and treatment.
  • Private home testing kits and online GP consultations are also available.
  • Common STIs: chlamydia, gonorrhoea, herpes, syphilis, trichomoniasis, HIV, HPV.
  • Treatment is straightforward and confidential.

Common STIs

  • Chlamydia: often silent. Test if under 25 or new partner.
  • Gonorrhoea: green discharge, pain on urination.
  • Genital herpes: painful blisters and ulcers.
  • Syphilis: painless ulcer then rash, then late complications.
  • Trichomoniasis: frothy discharge, irritation.
  • HIV: may have flu-like illness initially; otherwise silent.

How to get tested

  • NHS sexual health clinics — free, confidential, walk-in or appointment.
  • NHS home testing kits via local sexual health website.
  • Private at-home test kits with lab analysis.
  • Online GP consultation for advice and prescriptions.

How an online doctor can help

Online GPs can advise on which tests to do, interpret results, prescribe treatment for many STIs (e.g. doxycycline for chlamydia), and offer post-exposure prophylaxis (PEP) discussions urgently.

Frequently asked questions

Common questions UK patients ask about sexually transmitted infections.

How an online doctor can help

This article is for general information only and does not replace personal medical advice from a qualified doctor. Content is reviewed against UK NHS and NICE guidance by the OnlineDoctor24 editorial team and is not authored by a medical doctor. If your symptoms worsen or you are unsure, please book a consultation with a GMC-registered GP.

See a UK GP about this today

Same-day video or phone consultations with GMC-registered GPs. Prescriptions, sick notes and referrals when clinically appropriate.