Magnified depiction of chlamydia

Chlamydia is a sexually transmitted infection (STI) caused by Chlamydia trachomatis (shown above) , a bacterium that infects and parasitically lives within human cells, sometimes leading to several other disease states in both males and females.1 Chlamydia is the most frequently reported sexually transmitted bacterial infection in the United States, infecting approximately 2.86 million new individuals each year.2 For both males and females, chlamydia is most common among adolescents and young adults between the ages 14 to 24. Although chlamydia is spread primarily through sexual contact, it can also be spread from the genitals to the eyes by finger contact, or from mother to child during birth.2 It most commonly affects the human genitals or eyes, but can also cause renal (kidney) and oral infections.  Chlamydia infection of the eye, known as chlamydial conjunctivitis or trachoma, is one of the most common causes of blindness in the world.3 Chlamydia can be easily and effectively cured by prescribed antibiotics; however, if left untreated, chlamydia infections can result in serious reproductive damage along with a number of other short- and long-term health problems.4


Signs or symptoms of chlamydia infection may not always be noticeable. If symptoms are present, they will likely manifest differently depending on factors such as the biological sex of the infected individual and the site of infection.

Female Symptoms

In females, genital chlamydia infections are known as the “silent epidemic” because symptoms do not appear (also termed asymptomatic) in 70-95% of confirmed chlamydia cases.3 If not asymptomatic, some of the symptoms that typically appear in females include the following:

Anatomical diagram with "Healthy Female Reproductive System" including the uterus, Fallopian tube, ovary, and vaginal canal. The right side of the diagram includes the "Reproductive System with PID" with an abscess and pus.

While this list includes some of the most common symptoms associated with chlamydia infection, females can still have the STI without any or all of these symptoms ever appearing so all sexually active individuals should take appropriate precautions before engaging in sexual activity (such as getting tested and using condoms). Untreated cases of chlamydia can severely damage the female reproductive tract (including the fallopian tubes, ovaries, uterus, and cervix), ultimately leading to infertility or, in pregnant females, potentially fatal ectopic pregnancies. This situation is more likely to occur if symptoms of PID have developed.

Male Symptoms

In males, symptoms do not appear (also termed asymptomatic) in approximately 90% of confirmed genital chlamydia cases. Of the male cases that do show symptoms, infectious urethritis (inflammation of the urethra) is present in approximately 50% of the cases.3 The other symptoms that typically appear in males infected with chlamydia include the following:

  • Painful or burning urination
  • Unusual penile discharge (shown to the right), typically lighter in color and viscosity than that for gonorrhea
  • Swollen or tender testicles2

This list includes some of the most common symptoms associated with chlamydia infection in males; however, any sexually active male can still be infected without ever experiencing any of these symptoms, so all individuals should take appropriate precautions before engaging in any type of sexual activity.

In males, untreated chlamydia infection may cause epididymitis, or infection of the epididymis (a curved tube structure near the back of the testicles in which sperm mature). In rare cases such as the development of epididymitis, infection can result in fever, scrotal pain, testicular swelling, and irreversible sterility if not quickly and properly treated.3 Additionally, chlamydia in males could potentially lead to prostatitis or even Reiter’s Syndrome (also known as reactive arthritis). If left untreated, prostatitis can cause pain after sex, fever, chills, painful urination, and lower back pain.2 Reactive arthritis, which is a combination of arthritis (inflammation of joint tissue), conjunctivitis (infectious inflammation of the inner eyelids), and urethritis (inflammation of the urethra), most commonly affects young males; however, males of all ages are equally susceptible to the condition. In the United States, approximately 15,000 males develop reactive arthritis from chlamydia each year, and about a third of those males are permanently affected by it.3 Therefore, all sexually active males should get tested for STIs even if no unusual symptoms appear in order to decrease the chances of developing future health problems.

Chlamydial Trachoma Symptoms

For both males and females, chlamydia infection of the eyelids (sometimes called chlamydial trachoma or conjunctivitis) is especially dangerous, as it may result in permanent blindness if left untreated.3 The Chlamydia trachomatis bacterium has an incubation period of five to twelve days, after which the infected individual will begin to experience symptoms similar to those of pink eye (also referred to as conjunctivitis), as the eye appears red and inflamed. Soon after, the infection causes a harsh roughening of the inner eyelid (known as trachoma or granular conjunctivitis) which can deteriorate the individual’s cornea and eventually cause blindness.3 A visual example of advanced blinding trachoma is shown in the picture below. Chlamydial trachoma symptoms in males and females typically include the following:

  • Eye irritation
  • Unusual ocular discharge
  • Trichiasis (turned-in eyelashes)
  • Lymph nodes swelling in front of the ears
  • Photosensitivity (an immune system reaction to sunlight)
  • Heart rate increases
  • Corneal ulcer4

Early intervention of chlamydial trachoma is absolutely essential to avoid permanent scarring or blindness. Pay close attention to the exchange of bodily fluids when engaging in sexual activity, as fluid exchange can result in any physiological complications in the eye or other non-genital places. Overall, practicing safer sex can drastically reduce one’s risk of encountering negative consequences related to sexual activity and fluid exchange.

Risk Factors

Chlamydia is most commonly spread via vaginal, oral, or anal sex; however, it is possible for a mother to spread chlamydia to her child during delivery, resulting in pneumonia or a serious eye infection (chlamydial conjunctivitis) in the newborn if left untreated. Risk factors for chlamydia are similar to those of other sexually transmitted infections (STIs), including those in the following list:

  • Being under the age of 24
  • Being sexually active
  • Failing to use a condom consistently, properly, or during all sexual encounters
  • Having multiple sex partners within the last year
  • Having a prior history sexually transmitted infections (STIs)3

Although these risk factors increase the chances of contracting a chlamydia infection, they are also common risk factors for contracting other sexually transmitted infections (STIs) as well. Individuals who have chlamydia or other STIs are at higher risk of contracting another sexually transmitted infection, including gonorrhea and HIV. Those that notice these risk factors present in their own sexual behavior should take precaution and preventive measures (which are greater elaborated upon later in this article) in order to avoid contracting chlamydia or other STIs.3

Individuals experiencing possible symptoms associated with chlamydia infection after a sexual encounter should seek medical assistance for proper diagnosis and treatment. Due to the risk factors associated with current prevalence rates, the United States Centers for Disease Control and Prevention (CDC) recommends chlamydia screenings for the following groups of individuals:

  • Sexually active females age 25 or younger – The rate of chlamydia infection is highest in this group, so a chlamydia test is highly recommended every year and after having sex with each new partner.
  • Pregnant females – Testing during a female’s first prenatal exam is recommended to avoid pregnancy complications, including the spread of the infection to newborn children.
  • Males and females with one or more risk factors for STIs – Having one or more risk factor(s) for a sexually transmitted infection (STI) indicates a higher likelihood of infection if safe sex precautions are not taken. Getting a screening test and treatment for chlamydia early on will prevent further spread of the infection along with development of other conditions.3

A doctor or medical professional can provide access to STI screening tests. Individuals concerned that they may have contracted chlamydia infection or interested in prevention methods should consult their doctor.


Those who suspect that they may have the infection should avoid self-diagnosing and consult a professional healthcare provider who is specially trained to accurately diagnose and properly treat all STIs, including chlamydia. The testing and diagnosis of chlamydia is similar to the screening for any other suspected STIs.

Screening methods used to diagnose chlamydia typically include the following:

  • Swabbing – For females, a physician will swab the individual’s vaginal discharge for culture testing in a laboratory. For males, a physician will insert a thin swab into the end of the urethra (or the tip of the penis) to obtain a discharge sample. A physician may swab the anus instead if it is the suspected site of infection.
  • Urinalysis – A physician may ask their patient for a urine sample, which will be analyzed in a laboratory to detect the presence of an infection.2

It is recommended that all individuals who have been treated for chlamydia get re-tested by a healthcare professional three months following the initial treatment to diagnose if the infection has been completely eradicated from the patient’s body.


A multitude of white pills.

Chlamydia is treated with antibiotics, usually administered orally, but sometimes intravenously if the infection is severe enough. These antibiotics may include ofloxacin, doxycycline, or azithromycin. Ofloxacin or doxycycline are also useful in treating gonorrhea. Pregnant females should not take ofloxacin and doxycycline; instead, azithromycin or erythromycin should be administered.4 Patients undergoing treatment may receive a single dose, or may need to take the medication over a period of five to ten days. Most cases of chlamydia are resolved within one to two weeks.4 During this treatment period, abstinence from sex is an absolute necessity in order to prevent further spread of the infection to others. In some cases, chlamydia patients may actually transfer the infection back to the original carrier if he or she infects a regular sex partner. Having a previous history of chlamydia or chlamydia treatment provides no immunity against reinfection in the future.3 Chlamydia infection can be contracted more than once. If one partner has treated their chlamydia infection but another has not, engaging in sexual activity with the untreated individual may put one at risk for contracting the infection again.2


Most chlamydia infections can be treated successfully without complication, provided the individual receives regular STI screenings and seeks medical attention at the first presentation of symptoms.3 Overall, a doctor will usually predict a good prognosis if a patient receives proper treatment from a healthcare professional and finishes their entire course of prescribed antibiotics.


The only 100% effective method of preventing a chlamydia infection is abstinence from sexual activity. Although abstinence is the only certain way of preventing chlamydia transmission, there are other methods and preventative measures that individuals can follow to reduce the likelihood of contracting chlamydia infection and other STIs. Some measures helpful in preventing the contraction of chlamydia include the following:

A multitude of hot pink condoms.
  • Use condoms – Using a male or female condom (either latex or polyurethane) during sexual contact will significantly reduce one’s chances of infection.
  • Limit number of sex partners – Having sex with multiple partners greatly increases one’s risk of infection.
  • Get tested – Getting tested prior to engaging in any sexual activity is highly recommended. Seeking regular testing for chlamydia and all other STIs, especially after having sexual contact with a new partner, can be a life-saving measure for all partners involved.
  • Avoid douching – While douching is becoming less common as more females become aware of the potential harm it causes, many females do not realize that douching decreases the number of “good” bacteria present in the vagina, which help to fight incoming infections. Douching, in some cases, can even cause or worsen an infection such as chlamydia. Females should NOT douche.2

These preventative measures reduce the likelihood of contracting chlamydia as well as other sexually transmitted infections but do not guarantee full protection against STIs. Abstinence is the only way to eliminate the chances of contracting a sexually transmitted infection. Since chlamydia may be passed through intercourse, anal sex, or oral sex, anal and oral preventative measures should also be taken when engaging in these types of sexual activity.


If a patient is diagnosed with chlamydia infection, it is crucial that they inform their partners and past partners of the infection so others can also be properly diagnosed and treated for the infection. If a sexually active person is expressing chlamydial symptoms or genital changes, they should contact a medical professional.  A chlamydia patient should communicate with their partner about STIs, sexual health, and self-exams.

Asking a partner to be tested for STIs can be a very difficult conversation. It is a sensitive subject for most and may result in hurt feelings or other emotions. Although a person may demonstrate that they are looking out for the safety of themselves and their partner(s), some may take the request the wrong way and assume their partner believes they are dirty or sleep around. However, if a person clearly communicates the reasons for wanting their partner to be tested, and also gets tested with their partner, the conversation may go a lot smoother.

The best time to discuss getting tested for STIs is BEFORE engaging in sexual activity. It is not necessary to discuss exact numbers of sexual partners, since being tested ensures one is STI-free. However, it is necessary to tell a partner if one has or has had an STI in the past. Once sexual history has been talked about amongst new sexual partners, it is great idea to go get tested together.

Concluding Remarks

Green chlamydia.

Chlamydia affects people of all demographics and ethnicities. Any sexually active person having unprotected penile-vaginal, anal, or oral sex may be at risk. When engaging in sexual activity, use a form of barrier protection (such as the male condom) that protects against chlamydia infection and other sexually transmitted infections as well as unwanted pregnancy. We at SexInfo Online recommend getting tested for sexually transmitted infections frequently, especially if one is sexually active with multiple partners or engaging in sexual activity without protection. If one is seriously concerned for their sexual health or is experiencing any abnormalities we suggest seeing a doctor immediately. A doctor can test for various sexually transmitted infections, provide treatment, and offer other forms of STI prevention. It is also crucial to avoid sexual contact with others until the infection is treated and to communicate diagnosis of an STI with those who have engaged in sexual activity with the infected person so that they too can seek treatment.


  1. Ryan, Kenneth J., C. George Ray, and John C. Sherris. Sherris Medical Microbiology: An Introduction to Infectious Diseases. New York: McGraw-Hill, 2004.
  2. “Chlamydia At A Glance” Planned Parenthood, 2017.
  3. “Chlamydia – CDC Fact Sheet.” Center for Disease Control and Prevention, 7 May 2017.
  4. “Chlamydia.”Mayo Clinic. Mayo Foundation for Medical Education and Research, n.d. Web. 13 Mar. 2017.

Last updated: 5 June 2017.