Chlamydia

At a glance

  • Chlamydia is an infection with chlamydia bacteria. Some types of these bacteria are mainly transmitted during sex.
  • One of the possible symptoms is a watery or pus-like discharge from the vagina, penis, or anus.
  • Sometimes there are no symptoms, and the infection goes unnoticed. It can still be passed on to someone else, though.
  • If the infection isn’t treated with antibiotics, it can lead to pain, scarring and even infertility.

Introduction

Photo of two people lying in grass

Along with gonorrhea, chlamydia is one of the most common sexually transmitted infections (STIs). It is caused by Chlamydia trachomatis , and mainly affects the mucous membrane in the cervix, urethra (urine tube), or anus. It can cause a pus-like or watery discharge as well as pain and stinging when peeing. But it is also common to have no noticeable symptoms. Then the may be unknowingly passed on to sexual partners.

Left untreated, the can lead to and scarring in the internal sex organs. That can have serious consequences, particularly for women, even if the happened a long time ago. Untreated chlamydia infections are one of the most common causes of infertility in women.

So it’s a good idea to get tested if you think you might have chlamydia or if you have an increased risk of . If you test positive, the can be treated effectively with .

There are some types of chlamydia that cause illnesses that are much less common in Germany (affecting the eyes or airways, for example) and aren’t passed on through sex. This information is only about the STI.

Symptoms

Chlamydia in the lining of the cervix can cause a slimy, watery or pus-like discharge. If the get into the urethra, the person might need to pee more often and experience pain and stinging when they do. If the is infected, they might have itching or a rash around their anus, or blood and mucus in their poo.

Having said that, lots of infected people don’t have any symptoms: about 80 percent of women and 50 percent of men. There are hardly ever any symptoms when the happens through oral sex and the get into the mouth or throat. It might cause a sore throat, but that’s not very common.

Chlamydia only rarely affects the eyes. One way it could happen is by touching an infected part of a sexual partner’s body and then transferring the with your hand to your eye. That can result in conjunctivitis with red, itchy, or stingy eyes.

Causes and risk factors

Chlamydia are a type of bacteria. They enter cells, reproduce there, and then infect neighboring cells. The chlamydia that cause STIs are mostly found in the cells lining the genitals. The tend to infect the urethra and cervix, but they can also get into the , mouth, throat, or eyes.

You can get chlamydia by having sex with an infected person. The risk is higher if you have sex with lots of different partners and don’t use condoms.

In most cases, the are passed on during direct contact with sexual partners, but it’s also possible to catch chlamydia from sex toys. Infection through things like contact with surfaces such as sauna benches or shared towels is very unlikely.

It is also possible to spread the from one part of your body to another. One way this can happen is by touching your eyes with your hands.

Chlamydia can be passed on during birth too. This happens when pass from an infected woman’s genitals to her newborn baby.

Prevalence

Chlamydia is one of the most common sexually transmitted infections (STIs). Experts believe that around 100 million people worldwide get it every year. There are no exact figures available for Germany.

Slightly more women are diagnosed with a chlamydia than men. Most infections occur between the ages of 15 and 25 in women and up to the age of 35 in men.

Some other chlamydia types can cause an STI too – called lymphogranuloma venereum (LGV). They’re rare in Germany though and tend to occur more in tropical countries.

Outlook

If there are any symptoms, they usually start one to two weeks after the person was infected.

If the goes unnoticed and untreated, it can last a long time. The infected person can pass it to their sexual partners during that time. Another danger is that the can spread and cause complications in other parts of the body.

People who have been treated successfully for chlamydia can get it again. A past Infection does not make you immune.

Effects

Chlamydia infections don’t usually continue to spread in the body. But something known as “ascending is possible. That’s when the spread from the mucous membrane that was initially infected and then work their way up (ascend) the genital tract.

If the started in the penis, it can spread and cause in the prostate gland, seminal vesicles, sperm duct and epididymis.

If it started in the cervix, the can go on to infect the lining of the womb (endometrium), fallopian tubes and ovaries, and cause . Sometimes the spreads throughout a woman’s pelvis or around the liver.

This kind of can cause bleeding and scarring in the womb or fallopian tubes, which can result in the women becoming infertile or in an ectopic pregnancy (where the egg gets stuck in one of the fallopian tubes), miscarriage or premature birth.

In rare cases, joints can also become inflamed.

Diagnosis

If you have symptoms like an unusual discharge or problems when you pee and you think you might have caught something during sex, it’s a good idea to get yourself tested for STIs (including chlamydia). It is also advisable for people with an increased risk of STIs to get themselves tested regularly – no matter whether they have symptoms.

You usually have to give a urine sample for the test. This should be the first urine that comes out when you pee (first-catch urine). You can also do a smear test for chlamydia. The test sample can be taken from the cervix, vagina, urethra, , throat or eyes. The samples are sent to a lab to be tested for chlamydia.

Chlamydia tests can be done at family doctors’ or specialist practices (dermatology, urology or gynecology, for example). Local health departments and AIDS information centers offer tests too. Sometimes, you can take these tests anonymously. It is also possible to get advice over the phone and have a test kit sent to your home. Then you do the smear or collect the urine sample at home, send it to a lab for analysis and get the result by text message or phone.

Prevention

Condoms, femidoms (condoms for women) and dental dams can reduce the risk of chlamydia . But they can’t always prevent it. If you do develop typical chlamydia symptoms, it makes sense to get a test done quickly. A fast means you can get treatment fast too. That stops the being passed on to others and prevents complications.

Good to know:

In Germany, women who have statutory health insurance and are 25 or younger can get a chlamydia test once a year free of charge.

Chlamydia tests are also free for pregnant women. They’re offered as part of the first prenatal check-up. Antibiotic treatment is recommended if you test positive. That can prevent the baby from being infected during birth.

Regular testing is also a good idea for people who have an increased risk of for other reasons (like having unprotected sex with lots of different partners). They usually pay for these tests themselves.

Treatment

Effective treatment is available for chlamydia infections. It typically involves taking antibiotic (doxycycline) tablets for a week. Sometimes, other might be prescribed – if you are pregnant, for instance. Then the treatment is longer or shorter (sometimes just one day), depending on the antibiotic and the dosage. If there are complications, the treatment tends to last longer and involve a combination of medications.

It is important you don’t have sex until you finish the treatment or, if you’re given a one-day course of , for one week afterward. Experts recommend that anyone you had sex with in the last six months should also get tested – and treated, if necessary.

The standard procedure is to go back to your doctor for another test six to eight weeks after you started treatment. This is to check whether the are completely gone. These check-ups are a particularly good idea for pregnant women and people who still have symptoms despite treatment.

Further information

Please note that the services mentioned below are specifically for people living in Germany. Similar services are available in other countries. Germany’s Federal Institute of Public Health (BIÖG) (formerly the Federal Centre for Health Education (BZgA)) runs a website (www.liebesleben.de) that provides information about STIs like chlamydia and practical advice on how to prevent them. An English version of the website is also available. You can also get advice from the Federal Institute of Public Health online or over the phone.

The Deutsche Aidshilfe organization has information and telephone/online advice services too.

It also has an online search tool to help people find their nearest test center for chlamydia or other STIs.

Deutsche STI-Gesellschaft (DSTIG). Infektionen mit Chlamydia trachomatis (S2k-Leitlinie, in Überarbeitung). AWMF-Registernr.: 059-005. 2016.

Deutsche STI-Gesellschaft (DSTIG). Sexuell übertragbare Infektionen (STI): Beratung, Diagnostik und Therapie (S2k-Leitlinie). AWMF-Registernr.: 059-006. 2018.

Gemeinsamer Bundesausschuss (G-BA). Chlamydien-Test für Frauen bis 25 Jahre. Informationen zum Angebot der gesetzlichen Krankenversicherung. 2009.

Meyer T, Schüttler CG, Straube E et al. Schnelltest-Diagnostik sexuell übertragbarer Infektionen in niedrigschwelligen Einrichtungen. Gemeinsame Stellungnahme des RKI, PEI und der DSTIG. Bundesgesundheitsbl 2017; 60: 245-254.

Moll I. Duale Reihe Dermatologie. Stuttgart: Thieme; 2016.

Robert Koch-Institut (RKI). RKI-Ratgeber Chlamydiosen (Teil 1): Erkrankungen durch Chlamydia trachomatis. 2010.

Weyerstahl T, Stauber M. Duale Reihe Gynäkologie und Geburtshilfe. Stuttgart: Thieme; 2013.

Wiyeh AB, Mome RK, Mahasha PW et al. Effectiveness of the female condom in preventing HIV and sexually transmitted infections: a systematic review and meta-analysis. BMC Public Health 2020; 20(1): 319.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

Comment on this page

What would you like to share with us?

We welcome any feedback and ideas - either via our form or by gi-kontakt@iqwig.de. We will review, but not publish, your ratings and comments. Your information will of course be treated confidentially. Fields marked with an asterisk (*) are required fields.

Please note that we do not provide individual advice on matters of health. You can read about where to find help and support in Germany in our information “How can I find self-help groups and information centers?

Print page

Über diese Seite

Created on July 9, 2025

Next planned update: 2028

Publisher:

Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

Stay informed

Subscribe to our newsletter or newsfeed. You can find our growing collection of films on YouTube.