Being told you have chlamydia can feel unsettling, but it is one of the most common and most treatable sexually transmitted infections in the UK. The infection itself is usually straightforward to clear; what makes the biggest difference to your long-term health is what happens in the days and weeks after diagnosis. This article walks through the treatment, why partner notification matters, when a follow-up test is needed, and how to lower the chance of catching it again.
How chlamydia is diagnosed
Chlamydia is caused by a bacterium, Chlamydia trachomatis, and it very often causes no symptoms at all — which is exactly why testing is so important. Diagnosis is usually made with a nucleic acid amplification test (NAAT), carried out on a urine sample or a self-taken swab. Because so many infections are silent, many people are diagnosed through routine screening rather than because they felt unwell. If you would like more background on the testing process, our guide to STI testing in the UK explains what to expect.
When symptoms do occur, they can include unusual discharge, pain or burning when passing urine, bleeding between periods or after sex, and lower abdominal or pelvic pain in women, or discomfort and discharge in men. Chlamydia can also affect the rectum, throat and eyes depending on the type of contact, so a clinician may recommend testing from more than one site. The important point is that the absence of symptoms does not mean the absence of infection — and it certainly does not mean treatment can be skipped.
First-line treatment in the UK
Chlamydia is treated with antibiotics. Current UK guidance from the British Association for Sexual Health and HIV (BASHH) recommends a course of doxycycline as the first-line treatment for uncomplicated genital chlamydia, taken twice daily for a week. It is important to complete the whole course exactly as directed, even if any symptoms settle quickly, so the infection is fully cleared.
Doxycycline is not suitable for everyone. In pregnancy, for example, it is avoided, and an alternative such as azithromycin is used instead. A clinician will choose the right antibiotic for your circumstances and check for any allergies or interactions before prescribing. Doxycycline can make skin more sensitive to sunlight, so it is worth being careful about sun exposure during the course.
A few practical points help treatment go smoothly. Taking doxycycline with a full glass of water, and staying upright for a short while afterwards rather than lying straight down, reduces the chance of stomach irritation. Some people feel mildly nauseated, and taking the dose with food can help. The key thing is to finish every dose in the course even once you feel well, because stopping early can leave infection behind. If you are sick shortly after a dose or miss one, it is worth asking a clinician or pharmacist what to do rather than guessing.
Many people notice symptoms starting to ease within a few days of beginning treatment, but feeling better is not the same as being cleared — the antibiotic still needs its full course to do its job. Antibiotics for chlamydia are highly effective, so provided the course is completed as directed and there is no reinfection, treatment reliably clears the infection.
Why partner notification matters
Treating your own infection is only half the picture. If a recent sexual partner is not also tested and treated, it is very easy to pass the infection back and forth — a cycle sometimes described as reinfection. This is why partner notification is a core part of chlamydia care in the UK.
Recent partners need to be tested and treated even if they feel completely well, because chlamydia so often causes no symptoms. Sexual health services can help with this, including notifying partners on your behalf without naming you if you would prefer to stay anonymous. It can feel awkward, but it is a routine and confidential process, and it protects both you and the people you care about.
How far back partner notification needs to go depends on your circumstances and whether you had symptoms, so a clinician or sexual health adviser will guide you on which partners to contact. In many cases this covers partners from the past six months, or the most recent partner if that was longer ago. The aim is not to apportion blame — chlamydia can be present silently for a long time, so a positive test says nothing about when or from whom it was acquired — but simply to break the chain of transmission so it does not keep circulating.
Avoiding sex during treatment
To stop the infection spreading and to avoid immediate reinfection, you should abstain from sex — including oral sex, and sex with a condom — until you and your partner have both completed treatment and any advised waiting period. For a seven-day course of doxycycline, that generally means waiting until the course is finished; a clinician will confirm the exact timing for your situation. Resuming too early is one of the most common reasons infections appear to "come back".
Test of cure and follow-up
For most people with uncomplicated chlamydia, a routine test of cure is not required, because the recommended antibiotics are highly effective. However, a follow-up test is advised in certain situations — for example in pregnancy, if symptoms persist, if there is any doubt about whether treatment was completed, or in rectal infections. When a test of cure is needed, it is timed to avoid a false positive from leftover bacterial material, so your clinician will tell you when to take it. If you are ever unsure whether you need follow-up, it is always worth asking rather than assuming.
A test of cure is different from a test for reinfection. The first checks that the original infection has cleared; the second checks whether you have picked it up again from a new or untreated partner. This is why, even after a successful course, it can be sensible to test again if you have had a new partner or resumed sex with a partner who was not treated. Keeping these two ideas separate helps make sense of any advice you are given about coming back for a further test.
Reducing the risk of reinfection
Clearing chlamydia once does not make you immune — you can catch it again. Reducing that risk comes down to a few practical habits: making sure partners are treated before you resume sex, using condoms with new or casual partners, and testing regularly if you change partners. Guidance also commonly suggests a repeat test a few months after treatment in younger adults, because reinfection within that window is common.
The reason all of this matters is that untreated or repeatedly caught chlamydia can lead to complications. In women, the infection can spread to the upper reproductive tract and cause pelvic inflammatory disease, which can result in long-term pelvic pain and can affect fertility. In men, it can cause inflammation of the tubes near the testicles (epididymo-orchitis). These outcomes are uncommon with prompt, complete treatment, which is exactly why the follow-through — completing the course, notifying partners, and attending any advised follow-up — is worth taking seriously even when you feel perfectly well.
If you have questions about treatment, follow-up or testing, a UK-registered clinician can talk them through with you confidentially and advise on the right next step for your circumstances.