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FACT SHEET: Chlamydia (also known as “the clam” and “nongonococcal urethritis”; caused by bacterium Chlamydia trachomatis; also known generically as a “sexually transmitted infection” [STI], “sexually transmitted disease” [STD], and “venereal disease” [VD])

Date of Publication: May 19, 2015

Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • Potentially, if patient/client has active infectious oral disease. 

Is medical consult advised?  

  • Yes, if active infectious oral disease is suspected on the basis of history and/or examination. 
  • If patient/client has oral and/or reproductive/systemic manifestations suggestive of an STI, refer to primary care provider (e.g., physician or nurse practitioner) for definitive diagnosis (e.g., swab, urine test, etc., for chlamydia) and treatment (i.e., antibiotic). Instruct patient/client to reschedule dental hygiene appointment when oral chlamydial infection has been appropriately treated with an antibiotic and rendered orally non-infectious.

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • Potentially, if patient/client has active infectious oral disease.

Is medical consult advised? 

  • See above.

Is medical clearance required? 

  • Yes, if active infectious oral disease is suspected on the basis of history and/or examination. 

Is antibiotic prophylaxis required?  

  • No.

Is postponing treatment advised?

  • Yes, if active infectious oral disease is suspected on the basis of history and/or examination.

Oral management implications

  • Mode of transmission: Unprotected vaginal, anal, and oral sex with an infected partner, some of which can result in oral manifestations. The risk of transmission during oral sex (fellatio, cunnilingus, and anilingus) is increased if there are small cuts in the mouth (e.g., from dental work; brushing or flossing before/after oral sex; gum disease; or sharp foods). Risk during oral sex is also increased if there are sores on the mouth or genitals caused by rough or prolonged oral sex or an STI such as herpes or syphilis; if the person receiving oral sex is menstruating; and if there is holding of semen, vaginal fluid, or menstrual blood in the mouth for a long time or if it is swallowed. 
  • Transmission of chlamydia from an infected patient/client to oral health personnel is highly unlikely. Routine personal protective equipment (i.e., gloves, protective eyewear, and mask) should provide adequate protection from accidental transmission. 
  • In Ontario, chlamydia is a specified Reportable Communicable Disease (as per Ontario Regs 559/91 and amendments under the Health Protection and Promotion Act). Thus, physicians and laboratories are obligated to report this disease to the local Medical Officer of Health so the local public health unit can ensure affected persons are appropriately treated and contact tracing occurs to minimize further disease transmission.   
  • Sex partners of patients/clients with STIs should be assessed by an appropriate healthcare professional (e.g., physician) and treated as appropriate.   
  • To reduce acquisition and spread of oral cavity STIs, condoms or dental dams should be used for all oral-genital and oral-anal contact. 
  • Brushing or flossing of teeth should be avoided within 30 minutes of giving oral sex.  
  • Antibacterial mouthwash should be used after oral sex.  
  • The occurrence of certain STIs (including chlamydia) in children automatically warrants consideration of sexual child abuse, and dental hygienists should be familiar with their professional reporting obligations to the Children’s Aid Society. Additionally, palatal petechiae in children could be a sign of forced oral sex. 

Oral manifestations

  • When chlamydia is found in the throats of men and women having oral sex with an infected partner, it is typically asymptomatic.   
  • When oral chlamydia infection is symptomatic, symptoms typically develop 1 to 3 weeks after initial exposure, manifesting as pharyngitis (inflamed, sore throat), which may lead to painful swallowing. Other signs/symptoms include decreased appetite, cough, and fever.

Related signs and symptoms

  • A single STI is accompanied by additional STIs in about 10% of cases. Chlamydial co-infection with gonorrhea is common.   
  • In Canada, reported rates of chlamydia have been mostly rising since the late 1990s, with a dip during the COVID-19 epidemic starting in 2020. Chlamydia is the most commonly reported bacterial STI, and disproportionately affects younger adults, particularly women. In 2020, nearly 106,000 cases of chlamydia were reported, with 53% being among people aged 15 to 24 years old, and with females comprising 59% of all reported cases. 
  • Most infected men and women do not have overt signs or symptoms.  
  • Some patients/clients may experience the following signs/symptoms 2 to 6 weeks after exposure: discharge from the vagina (mucopurulent) or penis (mucoid or watery); dysuria (painful urination); pain during sexual activity; vaginal bleeding between menstrual periods or after sex; lower abdominal pain; burning or itching around the tip of the penis; and pain in the testicles. Proctitis1 may present as rectal pain, discharge, and/or bleeding.  
  • If not treated in women, chlamydia may spread from the cervix to the uterus and Fallopian tubes, causing pelvic inflammatory disease (PID) and pelvic pain. Similar to gonorrhea, tubal scarring, ectopic pregnancy, and infertility may result; in addition, some patients/clients may develop perihepatitis (“Fitz-Hugh-Curtis syndrome”), which is associated with right upper quadrant abdominal pain. In men, epididymitis2 (manifesting as pain in the testicles) and prostatitis may occur.  
  • Reactive arthritis can occur in men and women following asymptomatic or symptomatic infection. Sometimes this occurs as part of a triad of symptoms (with inflammation of the eyes and urethra), referred to as Reiter’s syndrome. 
  • Conjunctivitis and pneumonia may occur in newborns (resulting from infection from the birth canal).

References and sources of more detailed information

Date: December 23, 2014
Revised: January 8, 2020; January 17, 2024


1 Proctitis is inflammation of the lining of the rectum.
2 Epididymitis is inflammation of the epididymis, the coiled tube behind the testicle.

* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.