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Chlamydia is a sexually transmitted infection (STI). It can affect anyone who is sexually active and may not cause symptoms. Doctors may prescribe antibiotics and recommend other measures to treat it.

According to the Centers for Disease Control and Prevention (CDC), there were around 1.8 million cases of chlamydia in the United States in 2018. It is the most common sexually transmitted infection (STI) in the U.S.

Chlamydia often produces no symptoms, but it can lead to fertility problems. However, effective treatment is available.

In this article, we will discuss the symptoms, causes, diagnosis, and treatment of chlamydia.

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Most people with chlamydia do not notice any symptoms. According to research cited by the CDC, only around 10% of males and 5–30% of females experience symptoms.

It is also unclear how long it takes for symptoms to appear, but it may be several weeks.

In females

In females, symptoms of chlamydia may include:

  • a discharge from the cervix
  • easy bleeding
  • frequent or painful urination

If chlamydia spreads to the uterus and the fallopian tubes, it can result in pelvic inflammatory disease (PID). This, too, may not produce symptoms. However, it can affect fertility.

In males

In males, symptoms may include pain, tenderness, and swelling in the testicles or the urethra, the tube that carries urine.

Males and females

Both males and females may develop symptoms in the rectum and anus. The virus can infect these areas during anal sex or by spreading from the reproductive organs.

Symptoms include:

  • rectal pain
  • rectal discharge or bleeding

Contact with infected secretions can also lead to chlamydial conjunctivitis (pink eye).

Laboratory tests have found chlamydia in the throat of people who have had oral sex with someone who has the infection. However, this does not usually produce symptoms.

Anyone who has or suspects they have chlamydia must seek treatment to prevent long-term health consequences, including infertility and ectopic pregnancy.

Doctors will typically prescribe antibiotics to treat chlamydia. A person will usually take antibiotics as a pill.

The United States Preventive Services Task Force (USPSTF) recommend retesting at least every 3 months after treatment, depending on the individual’s risk factors.


Examples of antibiotics for chlamydia include:

  • Azithromycin: A single 1-gram (g) dose.
  • Doxycycline: 100 milligrams (mg) twice daily for 7 days
  • Ofloxacin: 300–400 mg once or twice daily for 7 days

Other medication options include erythromycin and amoxicillin. A doctor may prescribe one of these during pregnancy.

Adverse effects can sometimes occur, including:

Doxycycline can sometimes trigger a skin rash if a person spends time in the sun.

In most cases, the side effects will be mild. Anyone who experiences severe adverse effects should contact their healthcare provider. Do not stop taking the medication without first checking with a doctor.

According to one source, a course of antibiotics resolves chlamydia in 95% of cases. However, it is essential to follow the doctor’s instructions and complete the whole course of treatment.

Other aspects of treatment

The CDC recommend that people with chlamydia refrain from sex for 7 days:

  • after a single-dose treatment
  • while they complete a 7-day course of antibiotics

If a person has a diagnosis of chlamydia, they should inform any partners they have had sexual contact within the previous 60 days so that they, too, can seek testing and treatment.

If one partner does not receive treatment or does not complete the course of treatment, there is a risk of reinfection or transmitting the virus to someone else.

Sometimes, a doctor may also be treated for gonorrhea because the bacteria that cause the two infections often occur together.

To diagnose chlamydia, a doctor may carry out an examination to look for physical symptoms such as discharge.

They will also take either a urine sample or a swab sample from the penis, cervix, urethra, throat, or rectum.

Chlamydia screening

As chlamydial infection frequently presents no symptoms, health authorities often recommend screening for some people.

The USPSTF recommend screening for:

  • sexually active females under 25 years of age
  • pregnant women who are under 25 years or older if at high risk
  • males who are in a high-risk group
  • men who have sex with men annually and every 3–6 months if they are at high risk
  • people with HIV who are sexually active, at least once a year

How is chlamydia screening done?

A person can test for chlamydia at home or in the lab. They can take either a urine sample or a swab.

  • Females can take a swab, place it in a container, and send it to a laboratory.
  • Males will usually use a urine test.

A doctor can advise individuals on the best option. They may also recommend rectal or throat testing, especially for people who are living with HIV.

Home screening tests are available, but it is not always easy to do them correctly at home. A healthcare provider will usually recommend following up on any home tests by visiting a doctor’s office.

The person will likely need to provide a urine sample for a test to confirm a diagnosis. After treatment, they will need to retake the test to ensure that the treatment has worked.

If anyone wishes to try home testing, chlamydia screening test kits are available for purchase online.

Chlamydia is an infection by the bacteria Chlamydia trachomatis (C. trachomatis).

Chlamydia infection can affect several organs, including the penis, vagina, cervix, urethra, anus, eye, and throat. It can cause severe and sometimes permanent damage to the reproductive system.

A person can pass on chlamydia through unprotected oral, anal, or vaginal sex or through genital contact.

As chlamydial infection often has no symptoms, a person may have the infection and pass it on to a sexual partner without knowing.

It is not possible to pass on chlamydia through:

  • contact with a toilet seat
  • sharing a sauna
  • using a swimming pool
  • touching a surface that a person with chlamydia has touched
  • standing close to a person who has the infection
  • coughs or sneezes
  • sharing an office or house with a colleague who has the infection

According to the National Institutes of Health (NIH), a mother who has chlamydia infection can pass it on to her baby during childbirth.

Sometimes, the infection leads to complications for the infant, such as eye infections or pneumonia.

A female who has a diagnosis of chlamydia during pregnancy will need a test 3–4 weeks after treatment to ensure the infection has not returned.

Ways of preventing chlamydia or reducing the risk of infection include:

  • using condoms consistently and correctly
  • limiting the number of sexual partners
  • having a sexual relationship in which both partners are monogamous
  • regular screening
  • avoiding sex until treatment is complete

Early diagnosis and treatment can reduce the risk of complications.

Pelvic inflammatory disease (PID)

This is an infection of the ovaries, fallopian tubes, and uterus. It can lead to infertility.

According to the CDC, if chlamydia is left untreated, around 10–15% of females will develop PID.

This could lead to:

  • persistent pelvic pain
  • infertility
  • ectopic pregnancy, which can be life-threatening

In some cases, chlamydial PID can lead to an inflammation of the capsule that surrounds the liver. The main symptom is pain in the upper right side of the abdomen.

Pregnancy complications

The CDC also indicate that pregnant women who have chlamydia or their baby may experience:

  • preterm delivery
  • early rupture of the membranes
  • low birth weight
  • conjunctivitis or pneumonia in the newborn


This is an inflammation of the neck of the womb.


This is an inflammation of the fallopian tubes. It increases the risk of an ectopic pregnancy.


This is an infection of the urethra. The urethra is a tube that carries urine from the bladder out of the body. Chlamydia can inflame the urethra, resulting in pain and difficulty urinating.

Sometimes this occurs alongside conjunctivitis and reactive arthritis, which is a chronic type of inflammatory arthritis.


This can affect males. It is an inflammation of the epididymis, a structure inside the scrotum.

Signs and symptoms include red, swollen, and warm scrotum, testicle pain, and tenderness.

Chlamydia is a common, sexually-transmitted bacterial infection. It often produces no symptoms, but screening can show if a person needs treatment.

Without treatment, it can lead to complications that may have permanent effects. For this reason, treatment and screening are essential for those who may be at risk.