Conjunctivitis (Pink eye): What it is & How to Treat it

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girl with pinkeye pointing with finger

If your child says he or she feels a grain of sand in their eyes, watch out for watery, red or pink eyes, and sticky fluids coming from the eyes as well. It could be conjunctivitis. Here is an expert guide with all your answers, reviewed by pediatrician Dr. Eddie Cheung. 


What is conjunctivitis?

Commonly known as pink eye, conjunctivitis is an inflammation of the conjunctiva (a clear membrane covering the sclera and lining the inner eyelids). It can affect one or both eyes. The infection may affect one eye first then spread to the other.  


The classifications include infectious and non-infectious. Infectious conjunctivitis is more common. They are caused by bacteria, such as Haemophilus influenzae, Streptococcus pneumoniae and Chlamydia trachomatis (cause of STDs), and viruses like adenoviruses. Both are very contagious. 


Non-infectious conjunctivitis is a result of allergies or chemicals and irritants, such as air pollution. It is non-contagious. Dirty contact lenses are one common cause of it.  


Conjunctivitis is usually mild and can go away on its own without treatment. It lasts about 1-2 weeks and mainly affects children under the age of 5. Viruses account for up to 80% of all cases of acute conjunctivitis, but bacterial causes are more common in children. 


Your doctor will make a diagnosis based on the symptoms and an eye examination.  


It is best for your child to stay home until there is no longer any discharge from the eye(s) or 24 hours after antibiotic treatment.  


Incubation period: usually 1-3 days after exposure to bacteria, 1-12 days if it’s viral, and 3 days to several weeks for chlamydial conjunctivitis.  


Infectious period: Viral: while symptoms are present; bacterial: at least 24 hours after antibiotics have begun.

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How is conjunctivitis transmitted?

Infectious conjunctivitis can spread from person to person through:

  • direct contact with eye secretions 
  • indirect contact with items contaminated with eye secretions, e.g. towels, eye makeup, pillowcases and clothing
  • touching your eyes after touching an infected person or shaking hands
  • airborne droplets by coughing and sneezing
  • swimming in contaminated water
  • sexual contact or during childbirth from mothers to babies in chlamydial infections

Signs and symptoms of conjunctivitis

They may include:

  • Redness in the white of the eyes
  • Swelling of the conjunctiva
  • Excessive tearing
  • sandy or gritty sensation in the eyes 
  • Itchiness, irritation or burning sensation
  • Gooey discharge (pus or mucus) 
  • Eyelids sticking together due to discharge, especially first thing in the morning

In bacterial conjunctivitis, eye secretions are particularly sticky and whitish, yellow or yellowish-green in colour, but are more watery in the viral one. Both types can affect one or both eyes. Symptoms of respiratory infections like flu may also accompany viral conjunctivitis.  


As for allergic conjunctivitis, it usually occurs in both eyes and seasonally. Symptoms of allergy are simultaneously present, such as a stuffy nose, sneezing and a scratchy throat.

When should you see a doctor?

Newborns (younger than 28 weeks) with symptoms of conjunctivitis should be taken to see a doctor immediately.  Also, see your doctor if pink eyes occur along with:

  • heightened sensitivity to light 
  • eye pain 
  • blurred vision
  • Increased redness in one or both eyes
  • symptoms that worsen or do not improve after a few days of treatment
  • pre-existing eye conditions

How is conjunctivitis treated?


Viral conjunctivitis

There is no specific treatment. Antibiotics are not used as they do not kill viruses. Your doctor may prescribe antiviral medications if it is serious, for instance acyclovir. It usually clears up within 1-2 weeks. 


Bacterial conjunctivitis

It can be treated with antibiotic eye drops or ointment for 5-7 days. Examples of antibiotics include gentamicin and chloramphenicol. Symptoms often improve within 3-4 days after treatment. Note that ointments can cause blurred vision for up to 20 minutes. Recovery can take up to 2 weeks.  


If the bacterium Chlamydia is involved, your child will need oral antibiotics.  


Allergic conjunctivitis

Minimized exposure to allergens is one simple way to reduce symptoms. Some common medications are:

  • Antihistamines: reduce itchiness and watery eyes, e.g. chlorpheniramine
  • Decongestants: reduce redness of eyes, e.g. naphazoline. 
  • Mast cell stabilizers: reduce itchiness and watery eyes, e.g. cromolyn sodium.
  • Non-steroidal anti-inflammatory drugs: reduce inflammation, e.g. diclofenac.  
  • Steroids: reduce inflammation, e.g. prednisolone.
  • Artificial tears: contain no drugs and is for lubrication only. 

Warm compress also helps relieve eye discomfort and dryness. Soak a clean cloth in warm water and gently rub your eyes to remove discharge. Use a new cloth for another eye.  


Here are some hygiene measures to avoid getting or spreading conjunctivitis.  

  1. Clean your hands with soap and water or alcohol-based hand sanitizer regularly, for example after coughing and sneezing, or touching the infected eyes. 
  2. Wash pillows, sheets, face cloths and other linens used in hot water and detergent separately. 
  3. Avoid touching your eyes with unwashed hands. 
  4. Clean eyeglasses and cases used during the infection.
  5. Keep your house clean and avoid allergens to prevent allergic conjunctivitis. 
  6. Do not touch or rub your eyes as it can worsen symptoms.
  7. Do not use the same eye products for infected and non-infected eyes.
  8. Do not share personal items, such as eye drops, glasses, cosmetics and tissues. 
  9. Do not go swimming while infected.
  10. If you are pregnant, screening for and treating STDs can prevent conjunctivitis in newborns. 

Dr. Eddie Cheung 張蔚賢醫生 is a specialist in paediatrics. He received his paediatric training in Queen Mary Hospital and post-fellow paediatric cardiology training in Grantham Hospital/ Queen Mary Hospital. He is a Fellow of the Hong Kong College of Cardiology, the Vice President of Hong Kong Society of Paediatric Cardiology and Consultant of Hong Kong Association of Cleft Lip and Palate. He is currently working as Director of Paediatric Centre of HK Medical Consultants and serves as Infection Control Officer at the Hong Kong Adventist Hospital.

This article was independently written by Healthy Matters and is not sponsored. It is informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be relied upon for specific medical advice.

Dr. Cheung Wai Yin Eddie
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