Sore throat after oral sex: which STIs, and how to test

Key takeaways

• Most sore throats after oral sex are ordinary viral infections, but gonorrhoea, chlamydia, herpes and syphilis can all infect the throat, often with no symptoms at all.
• Only a throat swab, or a blood test for syphilis, tells you: a standard urine STI test does not check the throat.
• At Sexual Health Clinic London a gonorrhoea test and a chlamydia test each cost £104, can be taken as a throat swab, and give throat swab results in 2 to 3 days.
• A herpes PCR swab is £120.63, or a herpes blood test is £103.75, with results in 2 to 3 days.
• A syphilis blood test is £85 plus the £50 blood draw (£135 total), with results in as little as 24 hours.
• Difficulty breathing needs 999 or A&E, and difficulty swallowing or a high fever needs same-day medical advice rather than a routine test booking.

Most sore throats after oral sex are ordinary viral infections that would have happened anyway. But gonorrhoea, chlamydia, herpes and syphilis can all infect the throat, frequently without any symptoms, and a urine sample will not detect them. Only a throat swab, or a blood test in the case of syphilis, tells you what is actually there. If you have had oral sex with a new or casual partner, gonorrhoea throat swab testing is the direct way to check.

Which STIs can you catch in your throat?

Several STIs can infect the throat through oral sex, most of them without producing a symptom you would notice.

STIs that can affect the throat, their typical signs, and how they are tested.

Gonorrhoea in the throat

Pharyngeal (throat) gonorrhoea usually causes no symptoms, which is why it is easy to carry and pass on without knowing. When it does cause symptoms, a sore throat is the main one. A gonorrhoea test taken as a throat swab costs £104, with results in 2 to 3 days. Genital and rectal gonorrhoea can behave differently; our guide to gonorrhoea symptoms covers those sites.

Chlamydia in the throat

Oral chlamydia is contracted by giving oral sex to a partner who has a genital chlamydia infection, and most people with it have no symptoms at all. When symptoms do occur, a sore throat is the most likely one. A chlamydia test taken as a throat swab costs £104, with results in 2 to 3 days. Read more in our oral chlamydia guide, which covers how it spreads and what testing involves in more detail.

Herpes in the throat and mouth

Herpes simplex virus, usually HSV-1, can infect the mouth and throat and cause painful sores or ulcers, sometimes alongside a sore throat and difficulty swallowing during a first episode. If you have visible sores, a PCR swab of the sore is the most accurate herpes test, £120.63 with results in 2 to 3 days. Without visible sores, a blood test for HSV antibodies is available at £103.75, also with results in 2 to 3 days, though this checks for past exposure rather than confirming an active throat infection.

Syphilis sores in the mouth

Syphilis can be transmitted through oral contact with an infected sore (chancre), which can appear painlessly in or around the mouth and is easy to miss. A syphilis blood test is £85 plus the £50 blood draw (£135 total), with results in as little as 24 hours. The blood test can take a few weeks after infection to turn positive, so your clinician may suggest a repeat test later.

When a sore throat is probably not an STI

Most sore throats, including after oral sex, are caused by the same viruses that cause any other sore throat, and settle within a week or so on their own. A sore throat that is genuinely linked to an STI is more likely if it persists beyond the usual week, does not come with the classic cold symptoms of a blocked or runny nose, or follows oral sex with a new or casual partner.

Why a urine test won't find a throat infection

A standard urine test checks the genital tract, not the throat, so a negative urine result does not rule out a throat infection. If your only sexual contact has been oral, make sure your clinician knows so the correct sample site is used.

How throat testing works at our clinic

A throat swab is a quick, painless sample taken from the back of the throat by our clinical team. If you are also concerned about syphilis, a blood sample is taken at the same visit. Results are communicated to you confidentially: 2 to 3 days for chlamydia and gonorrhoea throat swabs and for herpes, and as little as 24 hours for syphilis. You can walk in seven days a week at 117A Harley Street. If you want broader reassurance, full STI screening packages cover chlamydia, gonorrhoea, syphilis, HIV and more from a single visit. Our guide to private STI testing in London explains how a confidential visit works.

Our same-day STI testing FAST Screen gives results in 6 hours, but it uses a urine sample or a swab and does not include a throat swab. A throat swab can be added to a urine sample for an extra charge.

Book a throat swab or syphilis blood test at 117a Harley Street: throat swab results in 2 to 3 days, syphilis results in as little as 24 hours.

When to see a doctor the same day

Call 999 or go to A&E if you are struggling to breathe or cannot swallow your saliva. See a doctor the same day, or call NHS 111, if you have a high fever, severe pain or difficulty swallowing alongside your sore throat. These need prompt assessment rather than a routine test appointment.

References

• NHS: Gonorrhoea
• NHS: Chlamydia
• NHS: Genital herpes
• NHS: Syphilis
• BASHH: UK national guideline for the management of gonorrhoea in adults
• UKHSA: Sexually transmitted infections surveillance data