Chlamydia: Causes, symptoms, treatment and prevention

Chlamydia infection is one of the most common sexually transmitted infections in the world and can affect both men and women. Let’s dive deep into what chlamydia is, its symptoms, how it spreads, its causes, prevention, and treatment. 

Image showing a microscopic view of bacteria invading cells

Key takeaways:

  • Chlamydia is a sexually transmitted infection that is spread through oral, anal, and vaginal sex. 
  • A bacterial specie called Chlamydia trachomatis, which primarily affects the lower genital tract, is what causes the chlamydia infection.
  • Common symptoms of chlamydia in both men and women include dysuria (painful urination), an unusual whitish discharge from the genitals, conjunctivitis (eye infection causing redness and swelling), and pneumonia (fluid buildup in the lungs) in neonates. 
  • Sexually active individuals under the age of 25, unborn children of women infected with chlamydia, gays, and bisexuals may be at a higher risk of getting a chlamydia infection. 

Sexually transmitted infections (STIs) or sexually transmitted diseases (STDs) are medical conditions that can develop as a result of having unprotected sexual intercourse with an infected individual. 

Chlamydia is among the STIs that are common in the general population. It can affect men, women, and, in some cases, children. Untreated chlamydia can become chronic and go from an infection to a sexually transmitted disease. 

According to recent data released by the World Health Organization (WHO), 128 million new chlamydial infections have been recorded annually worldwide since 2020.

What is chlamydia?

Chlamydia is a sexually transmitted infection caused by bacteria. So far, the infection has been listed by WHO as one of the world's most common and curable bacterial sexually transmitted infections.

The bacteria responsible for causing chlamydia attaches itself to its host's cell, and with the help of receptors, it gains access into the cell. The process is known as the mechanism of internalization.

People infected with chlamydia don't always show any signs or symptoms during the early stages of infection. However, symptoms of the infection will often begin to surface after a few weeks. 

Asymptomatic patients who later develop symptoms may experience some chlamydia-related complications such as urethritis (inflammation of the urethra), reactive arthritis, and susceptibility to contracting the human immunodeficiency virus (HIV) if the infection is left untreated for a long period of time. 

What causes chlamydia?

The chlamydia infection is a lower genital infection caused by a bacterium specie called Chlamydia trachomatis.

Chlamydia trachomatis, through the mechanism of internalization, attaches itself to a host cell and multiplies. However, the exact way in which the bacteria multiplies and spreads to other host cells is yet to be fully understood.

There are two other species of chlamydia that have effects unrelated to the male or female genitals. These species are: Chlamydia pneumoniae, which causes a respiratory infection called pneumonitis (a common influenza-like illness), and Chlamydia psittaci, responsible for another respiratory infection called psittacosis (a common mild illness with flu-like symptoms).

How chlamydia spreads

Chlamydia is spread through unprotected sexual intercourse, including oral sex with an already infected individual. It can also spread via vaginal and anal sex carried out without a physical barrier like a condom. 

Notably, chlamydia infection can still be contracted even when penetration or ejaculation does not occur after sexual intercourse. As such, semen doesn't have to be present for a person to contract a chlamydia infection. 

Other ways chlamydia can spread include:

  • The use of contaminated sex toys: Chlamydia can spread through the use of contaminated sex toys like dildos and vibrators that were used by an already infected person. 
  • From mother to child: Chlamydia is also spread from an infected mother to her baby during childbirth, resulting in health complications like ophthalmia neonatorum, also called conjunctivitis or pink eye (which causes redness of the eyes, swelling of the eyelids, and discharge of pus) or pneumonia in some infants.

Symptoms of chlamydia

The early symptoms of chlamydia are somewhat similar in both males and females. For most people, the symptoms of a chlamydia infection develop after one to three weeks of infection.

Symptoms of Chlamydia in men

Some symptoms of chlamydia in men include:

  • painful urination (dysuria)
  • Unusual watery, white, or cloudy discharge from the tip of the penis
  • Burning or itchy sensation in the urethra (the tube that carries urine out of the body)
  • Testicular pain (pain in the testis)

If these symptoms are left untreated, infected males may develop further complications like reactive arthritis (inflammation in various parts of the body) and swelling in the epididymis (the tubes that carry sperm from the testicles) and the testicles. These complications can affect male fertility.

Symptoms of Chlamydia in women

Some of the most common symptoms of Chlamydia in women include:

  • Dysuria (painful urination)
  • Unusual whitish, watery vaginal discharge
  • Pelvic and tummy pain
  • Nausea 
  • Pain during sex (dyspareunia)
  • Unusual bleeding after sex
  • Unusual bleeding between period

Untreated chlamydia infection in women can lead to complications like urethritis (inflammation of the urethra), cervicitis (inflammation of the cervix), reactive arthritis, and pelvic inflammatory disease (PID), which is one of the major causes of ectopic pregnancy and infertility in women.

Symptoms of Chlamydia in the throat

Symptoms of Chlamydia in the throat are usually uncommon and unnoticeable in most cases. Some studies regard it as an insignificant form of throat infection.

When chlamydia affects the throat, it’s typical symptoms are:

  • Sore throat
  • Hoarseness (unusually weak, scratched, or husky voice) 
  • Pain in the throat

Who is at a higher risk of developing chlamydia?

People who are at a higher risk of contracting chlamydia include:

  • People assigned female at birth: The global prevalence rate for chlamydia among people aged between 15 and 49 years in 2020, was estimated to be 4.0% for women and 2.5% for men. This suggests women are at a higher risk of developing chlamydia.
  • Young people: Younger people may be at a higher risk of developing chlamydia because they are more sexually active, and some of the infected individuals are asymptomatic. Unprotected sex with an asymptomatic person further spreads the infection among this age group. The National Health Service has advised sexually active individuals under the age of 25 to often test for chlamydia, as they run a high risk of getting infected.
  • People who had previous chlamydia infection: Individuals who had previously suffered from a chlamydial infection also run a high risk of getting reinfected.
  • Children whose mothers have chlamydia infection: Children of women who are infected with chlamydia have an increased risk of infection. According to the Centers for Disease Control and Prevention (CDC), untreated chlamydial infection can be linked to pregnancy complications like premature labor, premature rupture of membranes, and low birth weight. These increase the chances of the babies contracting the infection while moving down the birth canal during childbirth. 
  • Gay couples and bisexuals: Gay couples and bisexuals also run a higher risk of contracting chlamydia as well as Lymphogranuloma venereum (LGV), another type of STD caused by C. trachomatis. LGV is rare and has been the recent cause of proctitis (inflammation of the rectum) outbreaks in gay couples and bisexuals.

Chlamydia complications

Some complications of chlamydia include:

  • Urethritis, cervicitis, and prostatitis: When untreated, chlamydia can further cause inflammation of the urethra, inflammation of the cervix, and prostatitis (inflammation of the prostate).
  • Trachoma: Chlamydia is also the leading cause of trachoma, a disease of the eye that can result in irreversible blindness. It more commonly occurs in children.

Chlamydia also causes the following complications:

  • Salpingitis (inflammation of the fallopian tubes)
  • Endometritis (inflammation of the inner lining of the uterus)
  • Pelvic inflammatory disease (PID)
  • Ectopic pregnancy (pregnancy that occurs outside the uterus) 
  • Tubal factor infertility (blockage of the fallopian tubes) 

Diagnosis for chlamydia

It's important that a proper diagnosis of chlamydia is done to avoid the misdiagnosis of chlamydia infection with another STI or medical condition that has similar symptoms.

A chlamydia infection diagnosis is done by carrying out tests on both symptomatic and asymptomatic patients who have reason to believe they may have contracted the STI. 

Diagnosing Chlamydia is done using certain tests, like the Nucleic Acid Amplification Tests (NAATs) and cell culture.

To test for chlamydia, healthcare professionals collect samples from patients in two ways:  

  • Swab stick: This route of sample collection is mostly recommended for women as it involves using a sterile swab stick (a small cotton bud) to gently wipe over the area that might be infected. These areas can be inside the vagina or inside the anus.
  • Urine collection: This route of sample collection is mostly recommended for men and involves providing a urine sample one hour after you have previously urinated. 

Ideally, the patient's results should be provided within a period of 7 to 10 days after testing. 

Treatment for chlamydia

Doctors will often recommend treatment for patients who have tested positive for chlamydia.

However, if you've had any sexual activity with an individual who has an existing chlamydial infection, then you may be given treatment for the infection before getting your results. 

Chlamydial infections can be treated using antibiotics. The two very common and effective antibiotics used in the treatment of chlamydia infections are: 

  • Doxycycline 
  • Azithromycin

Due to certain health or physiological conditions, like pregnancy or allergic reactions, it's advisable not to self-medicate. Rather, seek your doctor's opinion on how best to treat the infection.  

Tips for preventing chlamydia infection

Here are some helpful things to do to prevent chlamydia infection: 

  • Ensure you use a condom every time you have sex. 
  • Opt for a dam (a piece of thin, soft plastic or latex) to properly cover the female genitals during oral sex or when rubbing female genitals together. 
  • Don’t share sex toys. 
  • Limit the number of sexual partners you have, and consider getting yourself and them tested regularly for STDs.
  • Abstain from sex, if that works for you. 

When to see a doctor

It's very important that you see a doctor if you suspect that you've come down with symptoms of chlamydia. Consider seeing a doctor if:

  • You or your partner show any symptoms of chlamydia.
  • You've had unprotected sexual intercourse with a new partner. 
  • Your condom splits while you're having sexual intercourse. 
  • You or your partner have had unprotected sex with multiple other people.
  • Your sexual partner tells you they have an STI.
  • You're pregnant or planning a pregnancy. 

It's also advisable that sexually active individuals age 25 or younger test for chlamydia at least once a year. Individuals who have contracted chlamydia in the past should test for a chlamydia infection every 3 to 6 months, as they may have a high risk of getting reinfected.

Frequently Asked Questions (FAQs)

Can chlamydia cause infertility?

Yes, chlamydia can cause infertility in males and females. Untreated chlamydia can cause male infertility when the Chlamydia trachomatis bacteria infects male reproductive organs like the testis and prostate.

In females, chlamydia can cause pelvic inflammatory disease and infection in the upper genital tract, which can damage female reproductive organs like the uterus and fallopian tube, leading to infertility.

Can chlamydia cause itching?

Yes, chlamydia can cause itching. For people who are symptomatic, irritation or itching around the genitals is one of the common symptoms they may experience.

Can chlamydia be cured?

According to the National Health Service (NHS), 95% of patients with chlamydial infections can be cured if they adhere strictly to the antibiotics prescribed to them by their doctors. This means you follow a doctor’s instructions and ingest the right dose of the medication you were prescribed.


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