Oral chlamydia: symptoms, causes, diagnosis, and treatment

When you think about chlamydia or other sexually transmitted infections (STIs), your first thought is likely about your genitals. But did you know that oral chlamydia is a thing? Read on to learn more about oral chlamydia, or in technical terms, pharyngeal chlamydia.

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You may think about cold sores on the mouth caused by the herpes simplex virus (HSV), but for the most part, you probably associate other STIs with genital infections. Chlamydia and gonorrhea can cause burning while urinating and discharge; syphilis can cause ulcers; HSV can cause blisters; human papillomavirus (HPV) can cause warts, and so on. However, many of these STIs can also cause symptoms in other parts of the body, called extragenital infections. 

Common parts of the body that are susceptible to extragenital infections are the rectum and mouth or throat since these parts of the body may also be involved in sexual contact. Being aware of infections outside the genital area is important for your sexual health, especially if you want to be screened for STIs. To truly make sure you don’t have certain STIs, you can’t just rely on a urine sample or vaginal swab. Instead, you need to check everywhere that may be at risk for infection.

Chlamydia is one of the STIs that can cause an extragenital infection and is sometimes found in the throat. This is sometimes called oral chlamydia or pharyngeal chlamydia. Chlamydia is caused by the bacteria Chlamydia trachomatis, so when you say you have pharyngeal chlamydia, it means you have an infection with the bacteria Chlamydia trachomatis in the throat.

In general, chlamydia is the most common reportable bacterial infection in the United States. The Centers for Disease Control and Prevention (CDC) estimate that there were four million cases of chlamydia in 2018. Additionally, since chlamydia does not cause symptoms in most people, the number of infected people is likely higher. It can be spread by vaginal sex, anal sex, and oral sex (CDC, 2021).

The most common sites of chlamydial infection are the urethra in men (causing urethritis) and the cervix in women (causing cervicitis). However, there has been a growing awareness of the need to identify extragenital infections. A few factors drive this:

• Rates of chlamydial infection are increasing.

• Extragenital infections can contribute to the spread of chlamydia.

• Untreated chlamydia can lead to severe consequences, including chronic pelvic pain, infertility, and an increased risk of ectopic pregnancy.

A review of the medical literature shows the rates of oral chlamydia in women, men who have sex with women (MSW), and men who have sex with men (MSM) are as follows (Chan, 2016):

• 0.2–3.2% (median 1.7%) of women have pharyngeal chlamydia

• 0–22.0% (median 1.6%) of MSW have pharyngeal chlamydia

• 0–3.6% (median 1.7%) of MSM have pharyngeal chlamydia

Pharyngeal chlamydia is spread through sexual contact. This primarily involves contact between the mouth of one individual and the anus, penis, or vagina of an infected sexual partner. This includes sexual activity like fellatio (contact between the mouth and penis, also called a blowjob), cunnilingus (contact between the mouth and vagina, also called “eating out”), and analingus (contact between the mouth and anus, also called “rimming”). 

You increase your risk of getting oral pharyngeal chlamydial infections by not using protection or having multiple sexual partners. One study looked into the rates of oral chlamydia infection in heterosexuals who had known or suspected genital infection and reported recent unprotected oral sex. It found that 7% of women and almost 3% of men had positive throat swabs (Wikström, 2010).

Not only can you get an oral chlamydia infection from oral sex, but if you have pharyngeal chlamydia, you may infect the genitals of a partner. One study found that 3.5% of MSW whose only exposure in the past three months was receiving fellatio from a woman were positive for urethral chlamydia (Marcus, 2011). 

Another study found that close to 5% of MSM whose only exposure in the past three months was receiving fellatio from a man were positive for urethral chlamydia (Bernstein, 2009). 

According to the CDC, there is less data on the transmission of chlamydia from an infected vagina to the throat, an infected throat to the vagina, an infected rectum to the throat, or an infected throat to the rectum (CDC, 2020).

The best protection against oral chlamydia is by avoiding unprotected sex. Using a complete barrier method reduces your risk of acquiring pharyngeal chlamydia during oral sex—this includes using a polyurethane or latex condom or a dental dam. Partial barriers or contraceptive methods such as birth control pills and spermicidal lube do not decrease your risk of getting pharyngeal chlamydia, or other STIs, from your sex partner. 

You are not likely to get oral chlamydia from mouth-to-mouth contact, including kissing or sharing a cup. However, a recent study suggested that gonorrhea, another STI, may potentially be transmitted by kissing. While the study did not find this to be the case with chlamydia, more research will help scientists learn more about the role of saliva in the transmission of STIs (Chow, 2019).

In the majority of cases, pharyngeal chlamydia is asymptomatic. If it does cause symptoms, they usually include sore throat (pharyngitis) or an uncomfortable feeling in the throat. However, the CDC does not consider pharyngeal chlamydia to be an important cause of pharyngitis (sore throats). More likely causes include viral infections, strep throat, allergies, reflux, and others (CDC, 2021).

Your healthcare provider takes a throat swab to check for pharyngeal chlamydia. However, checking throat swabs is not necessarily part of a routine chlamydia test. If your healthcare provider has only collected a urine sample or a vaginal swab, let them know that you would like to be checked for oral chlamydia as well. A urine sample or vaginal swab can come back negative for chlamydia even if you have a pharyngeal infection.

Untreated pharyngeal chlamydia could potentially infect a sexual partner. This could cause the sexual partner to experience genital symptoms, like vaginal discharge, urethral discharge, and a burning sensation while urinating. It also increases the chances of the chlamydia infection spreading back to you, infecting other parts of your body. 

Untreated genital chlamydia that spreads can cause serious complications like infertility, pelvic inflammatory disease (PID), urethritis, and epididymitis. It can also lead to an increased risk of ectopic pregnancy, a pregnancy outside of the uterus—this condition is a medical emergency and may even cause death.

Your healthcare provider can easily cure your chlamydia with antibiotics. The two main antibiotics typically used are a single dose of azithromycin (brand name Zithromax) or a 7-day course of doxycycline (brand name Vibramycin). More aggressive treatment may be necessary if other body areas are infected, depending on the severity.

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Current version

May 11, 2021

Written by

Mike Bohl, MD, MPH, ALM

Fact checked by

Chimene Richa, MD

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About the medical reviewer

Chimene Richa, MD

Dr. Richa is a board-certified Ophthalmologist and medical writer for Ro.