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When you think about sexually transmitted infections (STIs), your first thought may be about your genitals. Yes, you may also think about cold sores on the mouth caused by herpes simplex virus (HSV), but for the most part, you think about the genitals. Chlamydia and gonorrhea can cause burning with urination and discharge, syphilis can cause ulcers, HSV can cause blisters, human papillomavirus (HPV) can cause warts, etc.
- Infection with an STI somewhere else on the body is known as an extragenital infection.
- Oral (pharyngeal) chlamydia is primarily spread via contact between the mouth of one individual and the anus, penis, or vagina of an infected sexual partner.
- In the majority of cases, pharyngeal chlamydia is asymptomatic. If it does cause symptoms, they include sore throat (pharyngitis) or an uncomfortable feeling in the throat.
- Using a complete barrier method can reduce the risk of acquiring pharyngeal chlamydia during oral sex. This includes using a polyurethane or latex condom, or a dental dam.
However, many of these STIs can also cause symptoms in other parts of the body. Infection with an STI somewhere else on the body is known as an extragenital infection. This means an infection that is somewhere other than the genitals. 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 extragenital infections is important, 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/cervical 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 referred to as oral chlamydia or, more properly, 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.
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How common is pharyngeal chlamydia?
In general, chlamydia is the most common reportable bacterial infection in the United States. According to the Centers for Disease Control and Prevention (CDC), there were 1.7 million cases of chlamydia in 2017. Additionally, since chlamydia is asymptomatic in the majority of people, it is assumed that the number of people who are infected is actually much higher.
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:
- The fact that rates of chlamydial infection are increasing
- The fact that extragenital infections can contribute to the spread of chlamydia
- The fact that untreated chlamydia can lead to severe consequences, including chronic pelvic pain, infertility, and an increased risk of ectopic pregnancy
A 2016 review of the literature investigated the prevalence of pharyngeal chlamydia in women, men who have sex with women (MSW), and men who have sex with men (MSM) (Chan, 2016). It found that:
- 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
How do you get pharyngeal chlamydia? Can it be prevented?
Pharyngeal chlamydia is spread through sexual contact. This primarily involves contact between the mouth of one individual and the anus, penis, or vagina of a sexual partner who is infected. This includes 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”). High-risk behavior includes not using protection or having multiple sexual partners. One study looked into the rates of pharyngeal infection in heterosexuals who had known or suspected genital infection and reported recent unprotected oral sex (Wikström, 2010). It found that 7.0% of women and 2.7% of men had positive pharyngeal samples.
Not only can you get pharyngeal chlamydia from oral sex, but if you have pharyngeal chlamydia, you may infect the genitals of a partner. One study in MSW found that 3.5% of men whose only exposure in the past three months was receiving fellatio from a woman were positive for urethral chlamydia (Marcus, 2011). And one study in MSM found that 4.8% of men 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).
Using a complete barrier method can reduce the 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 and spermicidal lube do not reduce the risk of acquiring pharyngeal chlamydia.
It is not believed that pharyngeal chlamydia can be spread by mouth-to-mouth contact, including kissing or sharing a cup. However, a recent study suggested that gonorrhea may potentially be transmitted by kissing (Chow, 2019). More research needs to be done, and the study did not find this to be the case with chlamydia, but in the coming years, we may learn more about the role of saliva in the transmission of STIs.
What are the signs and symptoms of pharyngeal chlamydia?
In the majority of cases, pharyngeal chlamydia is asymptomatic. If it does cause symptoms, they 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 (CDC, 2016). More likely causes include viral infections, strep throat, allergies, reflux, and more.
How is pharyngeal chlamydia diagnosed?
To test for pharyngeal chlamydia, a healthcare provider takes a throat swab. However, this may not always happen – even if you ask to be screened for STIs. 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 pharyngeal chlamydia as well. A urine sample or vaginal swab can come back negative for chlamydia even if you do have a pharyngeal infection.
What are the complications of pharyngeal chlamydia?
Untreated pharyngeal chlamydia could potentially infect a sexual partner. This could cause the sexual partner to experience genital symptoms and increases the chances that it can spread back to you, infecting other parts of your body. Untreated genital chlamydia that spreads can cause serious complications like infertility and increased risk of ectopic pregnancy in women (pregnancy outside of the uterus that is a medical emergency and may even cause death).
How is pharyngeal chlamydia treated?
Chlamydia can be easily cured with antibiotics. The two main antibiotics that are usually 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 areas of the body are infected, depending on the severity.