Allergic conjunctivitis

Allergic conjunctivitis (also known as allergic eye) is inflammation of the white part of the eye and inside lining of the eyelids due to allergies.

image of a normal eye and an eye with conjunctivitisConjunctivitis is sometimes called 'pinkeye' and causes red, sore, gritty, watery, itchy eyes. There may be swelling of the eyelids and crusting on the eyelids overnight.

Causes

Conjunctivitis can be caused by allergies (eg, hay fever), irritants (such as shampoo, chlorine, make-up) or a bacterial or viral infection. If there is a pus-like discharge, which makes eyelids sticky it is more likely to be a bacterial infection. Bacterial conjunctivitis is very common, and both bacterial and viral conjunctivitis are very infectious. 

Allergies causing allergic conjunctivitis can be:

  • Airborne allergens, such as pollen (hay fever).
  • Dust mites, animal dander and feathers are the most common allergens.
  • Direct eye contact with allergic triggers such as cosmetics or preservatives (even some in eye drops).

Symptoms

The eyes are very sensitive to environmental allergens. A key difference with allergic conjunctivitis is both eyes are usually affected. Other symptoms include: 

  • Itchy, watery eyes (most common).
  • Puffy eyelids. Sometimes this is called 'allergic shiners". Sometimes enlarged blood vessels, or swelling of the eyelids.
  • People often also have other allergic symptoms such as acute onset of a blocked or runny nose.
  • Red, inflamed conjunctiva (seen if you pull your lower eyelid down and look on the inside) known as chemosis. (See chemosis video
  • Sore, gritty, irritated eyes is more likely to be due to dry eye, caused by problems with tear production.
  •  If allergic conjunctivitis is combined with nasal allergy, the condition is termed allergic rhinoconjunctivitis.

Duration

  • Seasonal at typical times of the year  when due to certain pollen, or grasses.
  • Continuous – occurs anytime with allergens such as dust mite or pets.
  • Sporadic – due to direct contact with an allergen such as cosmetics.

Treatment

For allergic conjunctivitis, one option is to find what causes your symptoms and avoid these if possible. Often this is difficult in which case you may need anti-allergy medicine or drops. 

    • Anti-allergy drops are available from a pharmacy or on prescription from your doctor.
    • Antihistamine tablets, such as loratadine can reduce the allergic response.
    • Sometimes mild steroid eye drops are needed. 

A recent Cochrane review by Castillo et al, June 2015, (1) combining the results of 30 studies has confirmed that:

  • topical antihistamines and mast cell stabilisers, alone or in combination, are safe and effective for reducing symptoms of seasonal and perennial allergic conjunctivitis.
  • There was insufficient evidence to discern which topical antihistamines and mast cell stabilisers are the most effective.

When medications do not provide enough relief another option is immunotherapy. Immunotherapy can be given under the tongue, nasally or by injection and is given over several years to build immunity to the allergen. A Cochrane review in 2011 by Calderon et al concluded that "overall, sublingual immunotherapy is moderately effective in reducing total and individual ocular symptom scores in participants with allergic rhinoconjunctivitis and allergic conjunctivitis.. more studies are needed." (2)

When to seek medical advice

Conjunctivitis does not usually affect your vision or eyesight. If you have any reduced vision, or if there is pain in the eye, or other symptoms such as fever or severe infection, visit your doctor straight away. You can also phone Healthline for advice on 0800 611 116.

If your eyes do not improve with treatment or you feel they are getting worse, consult your doctor or an optometrist.

To find an optometrist near you visit:

Self care

Washing your eyes:

  • Before touching your eyes, wash your hands with soap and warm water.
  • Dry hands with a clean (or disposable) towel.
  • Clean away any crusting or discharge with a disposable cotton swab and a weak salt water solution (1 tsp of salt in 500ml of cooled, boiled water).
  • Apply a clean cold facecloth (cold compress) over closed eyes. 

To clean your eyes, do not use cotton wool balls because they can unravel, leaving cotton in your eye. Surgical swabs from your chemist or disposable eye make-up removal pads are best.

image of woman using eye dropsIf using drops:

  • Always wash your hands first.
  • Open the container.
  • Pull the lower eyelid gently down with your forefinger to form a pocket.
  • Tilt your head slightly back and look up.
  • Holding the bottle between the thumb and forefinger, gently squeeze the recommended number of drops in the lower eyelid pocket.

To apply ointment:

  • Always wash your hands first.
  • Hold the tube between the thumb and forefinger.
  • Rest your hand against your nose to position the tip of the ointment tube.
  • Apply a small strip of ointment into the lower eyelid pocket.

Points to remember:

  • Do not touch the eye with the dropper or tube tip.
  • Discard all drops, solutions and ointments one month after opening to avoid bacterial contamination.
  • Some eye drops/products should only be used for a few days, check packet instructions.
  • Single-dose lubricant eye drops remain sterile until opened, if used before the expiry date.

Prevention

  • Try not to rub or touch your eye: if you touch anything you are allergic to, then your eye, this can trigger allergic conjunctivitis.
  • Before touching your eyes for any reason, wash your hands carefully. 
  • If your symptoms seem to come on after using eye make-up, change to low allergy eye products or discuss with your pharmacist. 
  • Use your own flannel, towels, pillowcases and bed linen (and change these regularly).
  • Contact lens wearers need to take extra care with lens hygiene and care procedures to avoid eye infection (and do not use contact lenses when you have conjunctivitis).

Learn more

Conjunctivitis factsheet  KidsHealth NZ
Conjunctivitis Root Eye Dictionary 
Allergic conjunctivitis Patient Info, UK
Eye allergy American Academy of Allergy Asthma & Immunology

References

  1. Castillo M, Scott NW, Mustafa MZ, Mustafa MS, Azuara-Blanco A. Topical antihistamines and mast cell stabilisers for treating seasonal and perennial allergic conjunctivitis. Cochrane Database of Systematic Reviews 2015, Issue 6. Art. No.: CD009566. DOI: 10.1002/14651858.CD009566.pub2
  2. Calderon MA, Penagos M, Sheikh A, Canonica GW, Durham S. Sublingual immunotherapy for treating allergic conjunctivitis. Cochrane Database of Systematic Reviews 2011, Issue 7. Art. No.: CD007685. DOI: 10.1002/14651858.CD007685.pub2
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