Adult Ophthalmology: Allergic Conjunctivitis

Allergic conjunctivitis is a relatively common eye condition that can affect men and women of all ages. 

Conjunctivitis affects the ‘conjunctiva’ – the thin membrane that covers the inside of the eyelids and outer white part of the eye – causing it to become inflamed and irritated. Although conjunctivitis can also be caused by bacterial and viral infections, which may be contagious, allergic conjunctivitis is caused by an allergic reaction so cannot be spread from one person to another. 

Symptoms of allergic conjunctivitis typically include red, bloodshot eyes that are itchy and watery. The eyes may also feel sore, sensitive and gritty. Symptoms can vary from person to person and range from mild to severe. For some, allergic conjunctivitis may cause the eyes to feel slightly irritated, while for others there may be intense and unbearable burning and itching. Most of the time both eyes are affected, although it is possible to get allergic conjunctivitis in one eye too.  

Allergic conjunctivitis is not generally associated with sight loss or long-term eye damage. However, in more rare cases, people can develop a condition called vernal keratoconjunctivitis. This is a chronic form of conjunctivitis that can result in damage to the cornea (the transparent film that covers the iris and pupil at the front of the eye), possibly affecting vision. 

The causes of allergic conjunctivitis include: 

Allergic conjunctivitis is caused by an allergic reaction. Exactly why some people develop allergies while others don’t isn’t entirely clear – but they are very common and often run in families, and occur due to an abnormal reaction within the immune system following exposure to specific allergens. These reactions can affect people in different ways and don’t always affect the eyes. 

Things that trigger an allergic reaction are known as ‘allergens’. Anything can potentially trigger a reaction, but common allergens include pollen (in fact, like hay fever, allergic conjunctivitis can be seasonal for some people), pets and animals, dust mites, moulds, and certain chemicals in cosmetics and cleaning products, for example. 

Exposure can occur in different ways too. For example, symptoms may be triggered as a result of breathing in airborne allergens, or by touching the allergen and then rubbing your eyes.  

Treatment of allergic conjunctivitis:  

Very mild allergic conjunctivitis that isn’t causing significant symptoms may sometimes clear up on its own after a week or two. However, many people will require treatment to help manage the underlying allergy as well as relieve symptoms. 

For mild to moderate symptoms with intermittent flare-ups, antihistamine eye drops for allergic conjunctivitis can help. If there are additional allergy symptoms beyond the eye (such as allergic rhinitis/congested and runny nose, or an itchy rash), antihistamine tablets may be required too. 

More severe allergic conjunctivitis may require steroid eye drops. These can be very effective but it’s important they’re only taken as prescribed and monitored by a specialist, as prolonged use can lead to an increased risk of side-effects that may need to be managed. 

Knowing how to care for your eyes during a flare-up can help too, which Mr Saurabh Jain is happy to advise on. For example, avoiding wearing contact lenses is advised until symptoms are under control, to avoid aggravating the eye further. A cool eye compress may help soothe itching and soreness, and wearing sunglasses can help protect sensitive eyes. It’s also a good idea to identify the specific allergens causing your symptoms so that, if possible, you can take steps to avoid them or minimise exposure. 

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Mr Saurabh Jain

Saurabh Jain Is a Consultant Ophthalmic Surgeon and Clinical Director of services at the Royal Free London NHS Foundation Trust.