About Chlamydia, Symptoms, Diagnosis & Treatment

What is it?

Chlamydia is one of the most common sexually transmitted infections (STI) in the UK, with up to one in ten sexually active young people thought to be infected. Chlamydia is usually passed from person to person through unprotected vaginal, oralor anal sex. It can also be passed on from contact with your partner’s genitals, even if there is no ejaculation. Rarely it can be transmitted by infected semen or vaginal fluid coming into contact with your eye and sometimes from sharing sextoys. Pregnant mothers can also pass the infection to their baby. Chlamydia isn't spread by kissing, hugging, sharing baths or towels, swimming pools, toilet seats, or sharing crockery and cutlery.

How does it affect you?

Up to 80% of infected women and 50% of infected men experience no symptoms. In women who do have symptoms, these may include a change in vaginal discharge, pain on urinating, pelvic pain or pain during sex, and bleeding in between periods or aftersex. In infected men with symptoms these may include a penile discharge, pain on urinating or discomfort at the tip or down the shaft of the penis and occasionally testicular swelling or pain.

If left untreated, chlamydia can cause serious complications such as reduced fertility, ectopic pregnancy, chronic pain and arthritis.

A positive rectal Chlamydia test, amongst gay or bisexual men, can sometimes be an indication that you are infected with a different and more aggressive strain of Chlamydia called Lymphogranuloma veneruem – LGV. Individuals testing positive forrectal Chlamydia will need to go to a clinic for LGV testing and treatment accordingly.


Chlamydia can be diagnosed from a urine sample (in men) or swab taken from the female vagina. Sometimes additional swabs from the throat or anus are taken.

It's possible to be tested within a few days of having sex especially if you have symptoms, but if you have no symptoms and just want a sexual health check-up, you may want to wait up to two weeks after the last sexual contact before performingthe test. This is because our tests may not reliably detect very early infection, and testing too early after a sexual risk may give you false reassurance (i.e. your test result may be negative when you are actually infected).


Chlamydia treatment is straightforward and has a success rate of 95% or more.

An infected person will usually receive a week long course of an antibiotic.  In some instances, if an individual has symptoms such as testicular pain or pelvic pain (in women), a longer course of antibiotics may be warranted.

If you have been found to have chlamydia in the vagina (only) or penis (only), you remain symptom free and the rest of your tests are negative you may be eligible to receive chlamydia treatment online or we can arrange for you to collect it ata local pharmacy. Otherwise you can attend a sexual health clinic for treatment.

If you have developed symptoms, or been found to have chlamydia in the throat or rectum you will need to attend your nearest sexual health clinic for treatment and maybe some more tests.

There are two possible antibiotic treatments that can be prescribed online by our doctors, azithromycin and doxycycline. The doctor will advise on which is the best option for you. Like all medicines, both azithromycin and doxycycline can have side effects. Remember, most people do not get any side effects at all, and that these antibiotics are considered safe and are commonly prescribed for the treatment of chlamydia.

The most common side effects caused by azithromycin are: nausea, vomiting, diarrhoea, abdominal pain and headache. These side effects should not last more than one to two days.

Rare side effects include rashes, pancreatitis, liver or kidney dysfunction, visual disturbances, breathing difficulties, blood system disorders and anaphylaxis.

The most common side effects caused by doxycycline are: sensitivity to light, indigestion and thrush. Rare side effects include: severe skin rashes, abdominal pain, diarrhoea, jaundice, difficulty swallowing, fever, headaches, blurred vision, palpitations, tiredness, bruising easily, chest pain, breathlessness and analphlaxis.

After you have begun your course of chlamydia treatment, any symptoms should start to improve within a few days and resolve completely within 2–4 weeks. If any symptoms persist, such as pelvic pain or pain during sex, it is important you re-attendthe clinic as further treatment or investigations may be necessary.

Contacting partners

If you are diagnosed with chlamydia you  should inform anyone you have had sex with within the last six months as they may also be infected. They should be advised to attend a sexual health clinic for a chlamydia test and may be offered treatmenton the day they attend. If you feel unable to inform previous sexual partners one of our Health Advisers will be able to notify them on your behalf without revealing your identity.

Maintaining good sexual health and preventing re-infection

You should not have oral, anal or vaginal sex during your course of chlamydia treatment or for seven days after the single dose of chlamydia treatment and also until your current partner completes their treatment and until both youand your partner’s symptoms have abated. This is to avoid being re-infected and requiring further treatment.

If you have been infected with chlamydia it is possible you may also have another STI. Therefore, it is advisable that you have a full sexual health screen for gonorrhoea, syphilis and HIV. To protect yourself use condoms and encourage your partnerto test for STIs also.

If you are under 25 and sexually active, it's recommended that you get tested for chlamydia every year or when you change sexual partner.

Under 25s who have chlamydia should consider re-testing three months after being treated because young adults are found to be at increased risk of catching chlamydia again.

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