Conjunctivitis | Pokenga whatu

The three main types of conjunctivitis are defined by their causes, these are: allergic, viral and bacterial. Viral and bacterial conjunctivitis are both infectious types of conjunctivitis. 

• Allergic conjunctivitis
  Conjunctivitis caused by allergies can be seasonal, occurring at certain times of the year (when due to pollen or grasses), or continuous or ongoing (when caused by allergens such as dust mite or pets). Allergic conjunctivitis is not infectious or contagious. Read more about allergic conjunctivitis.
• Viral conjunctivitis
  This is often caused by the same virus that causes the common cold. It usually begins in one eye, then affects the other eye within 24 to 48 hours. It tends to cause a thin watery or white mucous discharge and may be accompanied by symptoms of a cold. 
• Bacterial conjunctivitis
  This is caused by a bacterial infection and is common in infants and children. Typical symptoms include a sticky yellow or green discharge, most noticeable on waking up. 

Other causes

Inflammation of the conjunctiva can also be caused by direct contact with irritant chemicals such as cosmetics, chlorine from swimming pools or preservatives (even some in eye drops). People who wear contact lenses can get eye irritation due to the lens or contact lens solutions and are also more likely to get eye infections.

The common symptoms of conjunctivitis are:

• increased amount of tears
• gritty eyes – feels like there’s sand in your eyes
• itchy eyes
• swelling of your eyelids and crusting on your eyelids overnight.

Image: 123rf

This varies slightly depending on what is causing it:

• Allergic conjunctivitis
  The main symptom is itchy, watery eyes, which usually affects both eyes. It tends to be more common in people who have other allergies such as hay fever, asthma or eczema.
• Viral conjunctivitis
  This tends to cause a thin watery or white mucous discharge that usually begins in one eye, then affects the other eye within 24 to 48 hours. It may be accompanied by symptoms of a viral infection such as a common cold, cough or sore throat.
• Bacterial conjunctivitis 
  This generally affects one eye but can easily spread to both eyes. It produces a sticky white, yellow or green discharge that causes your eyelids to stick together. This is most noticeable on waking up.

The treatment for conjunctivitis differs depending on what is causing it.

Allergic conjunctivitis

This type of conjunctivitis gets better when you avoid the things that cause the allergy. Anti-allergy eye drops or antihistamine tablets can reduce the allergic response and relieve the symptoms. Antibiotic eye drops do not help allergic conjunctivitis.

Read more about hay fever and allergic conjunctivitis.

Viral conjunctivitis 

There is no effective treatment for common viral conjunctivitis. In most cases, it gets better on its own over a few days.

• Artificial tears eye drops can provide some relief from any discomfort.
• Clean away secretions from eyelids and lashes with cotton wool soaked in water.
• Viral conjunctivitis is contagious, so take care to wash your hands, use separate towels and avoid touching your face.

Bacterial conjunctivitis

Most cases of bacterial conjunctivitis are mild and it usually gets better on its own within a few days.

• You can clean away secretions from eyelids and lashes with make-up removal pads soaked in water or a clean facecloth.
• You can use artificial tears eye drops for relief from any discomfort.
• Antibiotic eye drops are not usually necessary for mild infection. 
• In some cases where the infection is more severe or persistent, antibiotic eye drops or eye ointment may be necessary.

Read more about antibiotics for bacterial conjunctivitis(external link)(external link)

Both viral and bacterial conjunctivitis are forms of infectious conjunctivitis, which means they can spread from one eye to another and from one person to another. You can care for yourself by carefully washing your eyes, as follows.

• Before touching your eyes, wash your hands with soap and warm water.
• Dry your hands with a clean (or disposable) towel.
• Clean away any pus, crust or discharge with a disposable cotton swab soaked in water.
• Wipe your eye once, from the end nearest your nose to the outside, then throw the swab away. Continue until your eye is clean.
• Wash and dry your hands again.

Cotton wool balls are not ideal because they can unravel, leaving cotton in your eye. Surgical swabs from your chemist or disposable eye make-up removal pads are best.

Contact lens users

• Do not wear lenses during infection and for 48 hours after it has cleared.
• Discard any disposable lenses and cases.
• If you are using non-disposable lenses, clean your lenses and containers completely before re-using.

Good hygiene can help prevent the spread of conjunctivitis:

• Try not to rub or touch your eye – you can spread infection to your other eye or to someone else.
• If you do touch your eye, wash your hands well afterwards.
• Use your own facecloth, towels, pillowcases and bed linen and change these regularly.

It is best to keep young children with infectious conjunctivitis home from daycare/school if the eye is sticky or weeping because the discharge is infectious.

Learn more

Conjunctivitis in children(external link)(external link)  KidsHealth NZ
Conjunctivitis factsheet (external link)(external link) KidsHealth NZ
Antibiotics for pink eye(external link)(external link) Choosing Wisely, NZ

Resources

Antibiotics for pink eye(external link)(external link) Choosing Wisely and American Academy of Ophthalmology, 2013
Watery eye(external link)(external link) Auckland Eye NZ, 2012

Related topics

Allergies
Allergic conjunctivitis
Eye drops
Eye ointment
Eye conditions

References

1. Causes, complications and treatment of a red eye(external link)(external link) BPAC, NZ, 2013
2. Conjunctivitis(external link)(external link) BPAC antibiotic guide, NZ, 2017 edition 

Conjunctivitis(external link) BPAC antibiotic guide 2017 edition 
Is this red eye a bacterial conjunctivitis? - a user's guide to correct treatment(external link) May 2016
Causes, complications and treatment of a red-eye(external link) BPAC NZ, 2013
Anti-inflammatory and allergy eye drops(external link) NZ Formulary
Anti-infective eye preparations(external link) NZ Formulary