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

Date of Publication: December 11, 2013
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Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • No

Is medical consult advised?

  • Yes, if infectious conjunctivitis (especially pink eye accompanied by discharge) is suspected 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, nurse practitioner, or pharmacist1) 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.
  • Yes, if an undiagnosed or untreated associated disease (infectious or non-infectious) is suspected to underlie the conjunctivitis.

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 with
    • bacterial conjunctivitis has been treated with an antibiotic (typically topical therapy with drops or ointment) for at least 24 hours or no longer has eye discharge (often purulent [“pus”])
    • viral conjunctivitis no longer has eye discharge (often watery) has resolved.

      In general, patients/clients with untreated or unresolved infectious conjunctivitis should be excluded from the operatory.

  • Possibly, if there is an associated infectious disease (e.g., COVID-19 or influenza), regardless of eye discharge, for which the patient/client is still in the period of communicability.

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 a risk of infectious disease transmission. 
  • 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 can also be 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 (in the case of bacterial conjunctivitis) or eye discharge (purulent or watery) 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, COVID-19, respiratory syncytial virus (RSV), Streptococcus pneumoniae, and Haemophilus influenzae type b (Hib).

Oral manifestations

  • None, given that this is a condition of the eye. (However, an associated disease may have oral manifestations.)

Related signs and symptoms

  • Conjunctivitis entails 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.2 It is a very common condition. 
  • The most frequent causes of conjunctivitis are viruses3, bacteria, and allergens. However, there are also other causes, including fungi, parasites, 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, depending on the underlying cause: 
    • increased tearing
    • thick discharge (“pus”), especially yellow-green (in infectious conjunctivitis, especially bacterial)
    • sticking together of eyelids or eyelashes (in infectious conjunctivitis, especially bacterial)
    • crusting of eyelids or eyelashes, particularly in the morning (in infectious conjunctivitis, especially bacterial)
    • watery discharge (more common in viral conjunctivitis)
    • itching, irritation, and/or burning (especially in allergic conjunctivitis)
    • foreign body sensation in the eye(s)
    • urge to rub the eye(s)
    • sensitivity to bright light
    • enlargement and/or tenderness of the preauricular node4 (in infectious conjunctivitis, especially viral) 
    • signs/symptoms of a cold, influenza (“flu”), or other respiratory infection (in infectious conjunctivitis, especially viral)
    • signs/symptoms of a middle ear infection (in infectious conjunctivitis, especially bacterial)
    • signs/symptoms of allergy, such as an itchy nose, sneezing, a scratchy throat, or asthma (in allergic conjunctivitis).
  • Viral infectious conjunctivitis, the most common type of short-term conjunctivitis, is typically mild, with symptoms being the worst on days 3−5 of infection. This type of pink eye often starts in one eye and spreads to the other eye within days. The condition usually clears up in 7−14 days without treatment and resolves without any long-term effects. Antibiotics do not help.5 Serious and less common types of viral conjunctivitis are those caused by the herpes simplex virus or varicella-zoster virus; these types of eye infections necessitate urgent medical intervention (including treatment with antiviral medication).
  • Bacterial infectious conjunctivitis is typically mild, with symptoms lasting as few as 2−3 days or up to 2−3 weeks. One or both eyes are affected. About 30% of infectious conjunctivitis cases are bacterial, although this percentage is higher in young children. 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. Serious and less common types of bacterial conjunctivitis include those caused by Neisseria gonorrhoeae or Chlamydia trachomatis, which if untreated, can lead to loss of vision.
  • Allergic conjunctivitis is caused by the body’s reaction to certain allergens. Both eyes are usually affected at the same time. 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 uveitis6 (which includes inflammation of the iris, the coloured part of the eye), 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; January 3, 2025


FOOTNOTES

1 As of October 2023, Ontario pharmacists are authorized to prescribe medications for 19 “minor ailments”, including conjunctivitis (bacterial, viral, and allergic).
2 The pink colour is due to dilatation of blood vessels.
3 A rare viral cause of conjunctivitis in the Canadian setting is zika virus disease, which is more common in tropical and subtropical locales.
4 The preauricular node is the lymph node in front of the ear (auricle).
5 Viral conjunctivitis may be managed with cold compresses (e.g., tea bags), decongestants, or artificial tears.
6 The uvea is middle layer of the eyeball, comprised of the iris, ciliary body, and choroid.


* 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.