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FACT SHEET: Conjunctivitis (also known as “pink eye” and “red eye; infectious conjunctivitis may be caused by viruses [often adenovirus], bacteria [usually staphylococci, streptococci, and Haemophilus species], or chlamydia; allergic conjunctivitis and irritant conjunctivitis do not pose an infectious riskto others)

Date of Publication: December 11, 2013

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

  • No

Is medical consult advised?

  • Yes, if infectious conjunctivitis is suspected (i.e., pink eye accompanied by eye discharge) and the patient/client is not already under medical care. While a medical consult for oral health reasons is not required, a referral to a primary care provider (e.g., physician or nurse practitioner) may be appropriate for definitive diagnosis, tailored treatment, and reduction of transmission risk. A medical consult is particularly important if the patient/client’s apparent conjunctivitis is accompanied by vision problems (such as persistent blurriness following eye cleansing, as well as sensitivity to light), moderate to severe eye pain, or intense eye redness, or if bacterial conjunctivitis being treated with topical antibiotics does not begin to improve after 24 hours of treatment. Patients/clients suspected of having viral conjunctivitis caused by the herpes simplex virus or varicella-zoster virus (the cause of chickenpox and shingles) should be seen urgently by an ophthalmologist.

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

  • No.

Is medical consult advised? 

  • Yes; see above.

Is medical clearance required? 

  • No.

Is antibiotic prophylaxis required?  

  • No.

Is postponing treatment advised?

  • Possibly. If active infectious conjunctivitis is suspected, deferral of dental hygiene procedures should be considered until patient/client has been treated with an antibiotic for at least 24 hours and/or eye discharge (watery or purulent) has resolved.

Oral management implications

  • The dental hygienist should distinguish between the main types of inflammation of the conjunctivae. The primary concern of the dental hygienist is untreated or unresolved infectious conjunctivitis. Allergic and irritant conjunctivitis do not pose an infectious risk. 
  • Allergic conjunctivitis may be accompanied by allergic rhinitis (i.e., nasal congestion and discharge), which may affect nose breathing. Seasonal allergic conjunctivitis and rhinitis most commonly occur during the spring, summer, and autumn, when environmental allergens such as grass, pollens, and ragweed are in abundance. 
  • Mode of transmission of infectious conjunctivitis is usually direct contact via fingers, facecloths, towels, etc., to the other eye or to other persons. Contaminated eye drops, contact lenses, and eye make-up are other potential vehicles of transmission. Large respiratory tract droplets can also spread viral or bacterial conjunctivitis.  
  • Bacterial conjunctivitis is highly contagious and spreads easily in daycare and primary school settings; this is why persons who are diagnosed with conjunctivitis, particularly children, should stay home until after treatment is started to avoid infecting others. Bacterial conjunctivitis is less frequent in children older than five years of age.
  • Viral conjunctivitis is also highly contagious and can result in epidemics. Most viruses that cause conjunctivitis are spread through direct hand-to-eye contact by hands contaminated with the infectious virus. Contact with infectious tears, eye discharge, fecal matter, or respiratory discharges can contaminate hands.
  • In the case of infectious conjunctivitis, avoid contact with infected eyes and eyelashes, as well as objects (e.g., towels) that have come in contact with infected eyes. 
  • For infectious conjunctivitis, ensure appropriate infection control measures are in place (e.g., gloves, hand washing, goggles) to prevent viral or bacterial spread from patient/client’s eyes or mouth to the eyes of the dental hygienist. If active infectious conjunctivitis is suspected, deferral of dental hygiene procedures should be considered until patient/client has been treated with an antibiotic for at least 24 hours and/or eye discharge (watery or purulent) has resolved. This approach will reduce risk of transmission to the dental hygienist.
  • If you, the dental hygienist, have infectious conjunctivitis, you should restrict yourself from patient/client contact as well as contact with the patient/client environment until you have no discharge from your eyes.
  • There is no vaccine that prevents all types of infectious conjunctivitis. However, there are vaccines that protect against several viral and bacterial diseases associated with conjunctivitis; namely, rubella, measles, chickenpox, shingles, Streptococcus pneumoniae, and Haemophilus influenzae type b (Hib).

Oral manifestations

  • None

Related signs and symptoms

  • Conjunctivitis involves inflammation and swelling of the conjunctiva (i.e., the thin layer of tissue that lines the inside of the eyelid and covers the white part, or sclera, of the eyeball). It is often called “pink eye” or “red eye”, because it can cause the sclera of the eye to take on a pink or red colour. It is a very common eye condition. 
  • The most common causes of conjunctivitis are viruses, bacteria, and allergens. However, there are also other causes, including chlamydia, fungi, chemicals, certain diseases, and contact lens use. The conjunctiva can also become irritated by foreign bodies in the eye and by air pollution.  
  • Signs and symptoms associated with conjunctivitis, in addition to pink/red eye colour and conjunctival swelling, can include: 
    • Increased tearing
    • Discharge of pus, especially yellow-green (more common in bacterial conjunctivitis)
    • Crusting of eyelids or lashes, especially in the morning
    • Itching, irritation, and/or burning
    • Foreign body sensation in the eye(s)
    • Urge to rub the eye(s)
    • Sensitivity to bright light
    • Enlargement and/or tenderness of the lymph node in front of the ear 
    • Symptoms of a cold, flu, or other respiratory infection 
    • Symptoms of allergy, such as an itchy nose, sneezing, a scratchy throat, or asthma (in allergic conjunctivitis) 
  • Viral infectious conjunctivitis is typically mild, with symptoms being the worst on days 3−5 of infection. The condition usually clears up in 7−14 days without treatment and resolves without any long-term effects. Antiviral medication can be prescribed by a physician to treat more serious and less common forms of viral conjunctivitis, such as those caused by the herpes simplex virus or varicella-zoster virus
  • Bacterial infectious conjunctivitis is typically mild, with symptoms lasting as few as 2−3 days or up to 2−3 weeks. Many cases improve in 2−5 days without treatment. However, topical antibiotics are often prescribed to speed up resolution of the infection and to reduce transmissibility risk to others. Approximately 32−50% of infectious conjunctivitis cases are bacterial.
  • Allergic conjunctivitis is caused by the body’s reaction to certain allergens. It occurs more frequently among people with other allergic conditions, such as hay fever (allergic rhinitis), asthma, and eczema. It may occur seasonally when pollen counts are high, or year-round due to indoor allergens, such as dust mites and animal dander. It improves once the allergen is removed or after treatment with allergy medications, such as topical antihistamines. 
  • Not all cases of eye redness are due to conjunctivitis. Inflamed eyes may also be due to acute uveitis (which includes inflammation of the iris), acute angle-closure glaucoma, and corneal disorders. These conditions require urgent medical intervention.

References and sources of more detailed information

Date: June 16, 2013
Revised: November 18, 2019