Everything you need to know about chlamydia

Megan Alphabiolabs

By Megan Souness, Technical Manager for Health Testing and Covid‑19 at AlphaBiolabs
Last reviewed: 28/10/2022

This guide contains everything you need to know about chlamydia including what it is, signs and symptoms of the infection, how it’s treated, and how often you should get an STI/STD test for chlamydia
Table of contents
  • What is chlamydia?
  • How common is chlamydia?
  • What are the symptoms of chlamydia?
  • What are the symptoms of chlamydia in men?
  • What are the symptoms of chlamydia in women?
  • What does chlamydia look like?
  • Is chlamydia contagious?
  • How do you get chlamydia? How is it spread?
  • Can you get chlamydia from kissing?
  • Can you get chlamydia without having sex?
  • How long does chlamydia last?
  • How long can you have chlamydia without knowing?
  • What should you do if you have chlamydia?
  • What is the treatment for chlamydia?
  • Can you get an STI test for chlamydia?

What is chlamydia?

Chlamydia is a common bacterial infection caused by the bacteria Chlamydia trachomatis and is usually spread via sexual contact and genital fluids (semen or vaginal fluid).

It is one of the most common sexually transmitted infections (STIs) in the UK and is especially prevalent among sexually active teenagers and young adults.

Because many people with chlamydia are often asymptomatic (do not experience symptoms), the infection is routinely transmitted by people who do not even know they are infected.

However, if left undiagnosed or untreated, chlamydia can cause serious long-term health complications, including pelvic inflammatory disease (PID) and infertility in women.

In rare instances, men may develop epididymitis or epididymo-orchitis (inflammation of the testicles).

How common is chlamydia?

Chlamydia is the most contracted STI/STD in the UK. This is because many people with chlamydia often experience no symptoms, meaning it is easily transmitted during unprotected sex by those who do not even know they have it.

According to figures released by the UK Health Security Agency, 978,307 chlamydia tests were performed throughout 2021 on young people aged between 15-24, via the National Chlamydia Screening Programme (NCSP).

A total of 87,905 chlamydia diagnoses were registered among 15-24-year-olds during this period.

What are the symptoms of chlamydia?

Although chlamydia can often be symptomless, men and women who do have symptoms may experience:

  • More frequent urination
  • Pain when urinating
  • Unusual discharge
  • Itching, burning or irritation

What are the symptoms of chlamydia in men?

Symptoms of chlamydia that are specific to men include:

  • Clear or cloudy discharge from the tip of the penis
  • Pain and swelling around the testicles
  • Burning and itching around the opening of the penis

If left undiagnosed or untreated, chlamydia can cause further health complications in men including:

  • An infection of the epididymis (the tube that carries sperm away from the testes)
  • Proctitis (inflammation of the rectum)

What are the symptoms of chlamydia in women?

Symptoms of chlamydia that are specific to women include:

  • Abnormal vaginal discharge that may have an odour
  • Bleeding between periods
  • Painful periods
  • Pain during sex
  • Itching or burning in or around the vagina

If left undiagnosed or untreated, chlamydia can cause further health complications in women including:

  • Pelvic inflammatory disease (PID), which can damage the fallopian tubes (the tubes that connect the ovaries to the uterus)
  • Increased risk of ectopic pregnancy (when the fertilised egg implants and develops outside the uterus)
  • Premature births

Mothers can also pass chlamydia to their children during childbirth, which can cause eye infections, blindness, or pneumonia in new-born babies.

What does chlamydia look like?

Although many people with a chlamydia infection do not experience any physical signs, there are some tell-tale indicators of which people should be aware.

In women, visible signs can include:

  • Unusual discharge – this can include pus, blood, and can even have a stringy, mucus-like consistency
  • Inflammation of the cervix – also known as cervicitis, this can cause the outer portion of the cervix to appear very red, and will likely only be visible during examination by a medical practitioner
  • Signs of swelling during a pelvic examination – tenderness in the abdomen during an examination by a nurse or doctor could indicate swelling in the uterus and fallopian tubes

In men, visible signs can include:

  • Discharge from the urethra – usually clear and stringy
  • Swollen testicles – which appear red and enlarged
  • Anal bleeding or discharge

Visible signs of chlamydia affecting both men and women can include painful, red joints such as knee-joints, which can be caused by chlamydia-related arthritis, and conjunctivitis, an eye infection resulting in discharge.

Is chlamydia contagious?

Chlamydia is caused by a bacteria called Chlamydia trachomatis, which is highly contagious, and can be passed on via intimate sexual contact such as vaginal, anal, and oral sex.

It can also be spread through genital fluids (vaginal fluids and semen), without penetration. In rare instances, if the eyes become infected, it can also be transmitted via ocular fluids.

Because the infection is highly transmissible, it is important for anyone having regular unprotected sex with multiple partners to get tested regularly for chlamydia.

This can help ensure any infection is caught quickly and can help prevent the spread of the infection to other people.

Chlamydia cannot be spread through casual contact such as hugging, kissing, using a toilet, or sharing food and drinks.

How do you get chlamydia? How is it spread?            

Chlamydia is spread via sexual contact such as unprotected vaginal, anal, and oral sex, or by genital touching, if bodily fluids such as semen and vaginal fluids are transferred between partners.

A person can also catch chlamydia:

  • If infected genital fluids (semen/vaginal fluids) get into the eyes
  • By sharing sex toys that have not been cleaned or covered with a condom each time they are used

Pregnant women infected with chlamydia can also pass the infection on to their baby.

You cannot catch chlamydia during casual contact such as sharing baths or swimming pools, kissing, hugging, or by sharing food and drinks.

Can you get chlamydia from kissing?

You cannot contract chlamydia from kissing.

Chlamydia can only be passed on via genital fluids (semen/vaginal fluid) through genital touching, or via sexual contact such as vaginal, anal, or oral sex.

Can you get chlamydia without having sex?

Chlamydia can only be spread via infected genital fluids (semen/vaginal fluids). However, a person can still become infected with chlamydia even if there is no penetration, ejaculation, or orgasm.

The infection can be easily spread via genital touching such as when an infected person’s genitals come into contact with their partner’s genitals.

In rare instances, if chlamydia infects the eyes, it can also be spread through ocular fluids.

How long does chlamydia last?

A person with chlamydia will remain infected – and able to pass the infection on to other people – until they have been treated for the infection.

Once diagnosed, chlamydia can be easily treated using antibiotics.

How long can you have chlamydia without knowing?

Every sexually transmitted infection (STI) has a different incubation period: the amount of time it takes from when a person is first infected to when they begin to experience symptoms, and the infection becomes detectable by an STI test.

The incubation period for chlamydia is between one and three weeks from when a person is first infected. However, some people can have chlamydia for months or even years without knowing.

This is because it is common for people with chlamydia not to have any symptoms at all (asymptomatic).

This makes regular testing for chlamydia important. Not only can it give you peace of mind if you are not infected, but it can also help ensure that any infection is detected early (before symptoms start or become more severe), enabling you to seek the correct treatment, and preventing the spread of the infection to other people.

If left undiagnosed or untreated, chlamydia can cause serious long-term health complications, including infertility in women.

What should you do if you have chlamydia?

If you have had an STI test, such as those offered by AlphaBiolabs, and your results show that a chlamydia infection has been detected, you MUST contact your GP as soon as possible.

You may also want to visit your local sexual health clinic for further guidance and treatment options.

You should also abstain from sexual contact until the infection has been successfully treated with antibiotics and inform any sexual partners immediately.

It is very important to take your prescribed antibiotics correctly, to ensure that the infection is treated quickly and effectively.

What is the treatment for chlamydia?

Once diagnosed, chlamydia can be easily treated with prescribed antibiotics. Your doctor or sexual health clinic will be able to prescribe you with suitable antibiotics to clear the infection.

Can you get an STI test for chlamydia?

It’s never been easier to order an STI test for chlamydia.

Because the symptoms of chlamydia are similar to other common STIs including gonorrhoea, trichomoniasis and mycoplasma genitalium, many STI testing providers – including AlphaBiolabs – will test for chlamydia alongside these other infections.

How often you get an STI test for chlamydia and other common pathogens can depend on your age, gender, risk factors, and how sexually active you are.

For men and woman in England who are sexually active and aged under 25, a chlamydia test is recommended once a year, or whenever you have sex with new or casual partners and are not using protection (condoms).

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Megan Souness, AlphaBiolabs

Megan Souness

Technical Manager for Health Testing and Covid‑19 at AlphaBiolabs

Megan joined AlphaBiolabs in 2020 and holds the role of Technical Manager, playing a fundamental part in the research and development of new health testing services at AlphaBiolabs.

In addition to developing new services, Megan oversees the day-to-day processes in the Health Laboratory, managing the in-house validation and training of all new workflows, and ensuring the lab operates to the highest possible quality technical standards.

During her time at AlphaBiolabs, Megan has played a key role in the development and launch of the company’s health testing services, including the introduction of a full suite of at-home STI tests, and the progression of the laboratory to ISO 15189 standards.

Megan holds a BSc in Biochemistry, an MSc in Biological Sciences, and is a member of the British Association for Sexual Health and HIV (BASHH).

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