Prescription: Allergic conjunctivitis

Every fortnight Dr Sunita Agarwal highlights a common, but often ignored, medical problem


Allergy is one of the most common causes of conjunctivitis. Patient history can be critical, as many allergic conjunctivitis patients report associated systemic environmental allergies. A variety of antigens have been implicated in allergic conjunctivitis, with seasonal pollens, animal dander, and dusts most commonly implicated.

The most common type of ocular allergy is seasonal and perennial allergic conjunctivitis. Seasonal allergic conjunctivitis (hay fever conjunctivitis) is the more common type accounting for the majority of allergic conjunctivitis cases. It is related to specific pollens that spore during certain seasons. Perennial allergic are often related to animal dander, dust, or other allergens that are present in the environment year round. Symptoms are similar to seasonal allergic conjunctivitis: however, they tend to be milder.

Seasonal allergic conjunctivitis generally occurs in the spring months (grass pollen induced), and in the late summer months (ragweed pollen induced). Itching is a dominant symptom in seasonal allergic conjunctivitis diagnosis, as well as watery/mucus discharge, burning, and redness.

How does it present itself?

Patients often manifest a constellation of non-specific symptoms, though itching is usually predominant. Associated symptoms include redness, swelling, tearing and occasional discharge. Symptoms of seasonal allergies generally include red, itchy and watery eyes. People affected by hay fever and other seasonal allergies also experience symptoms involving the nose and throat.

What are the treatment options?

There are various topical and oral medications readily available at local. For serious cases, a variety of prescription medications are available. Most medications fall into the antihistamine category, either topical or oral. Both work to block the release of histamine, which causes many of the symptoms. Orally ingested antihistamines may partially relieve ocular symptoms but more so other systemic effects such as a runny nose and sneezing. Some oral antihistamines produce unwanted side-effects such as drowsiness, irritability and dryness. They work best if taken before exposure to the allergen, if not, they are best taken at night due to ensuing drowsiness. Topical antihistamines, in the form of eye drops, may prove the most effective way to get relief. Unlike oral medications, eye drops allow the medication to directly treat the affected eyes. Many contain both an antihistamine and a decongestant. Applied when necessary, these drops can alleviate most of the annoying symptoms within minutes. Steroid eye drops are most efective, but have to be monitored if used for a long time due to the side effects of long standing use. Associated dryness may be treated with artificial tears and silicon lacrimal plugs.

How can it be prevented?

Keep windows in your home and car closed during the pollen season: use air conditioning instead. If you suffer badly, some cars have filters fitted that remove the pollen from incoming air. Avoid outdoor activities such as gardening. Avoid going for walks in the morning and early afternoon when pollen release is at its height. Wash your hands, face and hair often to rid them of pollen that may accumulate. Don't rub your eyes. Rubbing stimulates the release of chemicals which can make you eyes even itchier. Use cold compresses to alleviate the itching. Relief from seasonal allergic conjunctivitis comes in many ways. Allergy shots, a desensitisation process, can be helpful for some people in reducing symptoms and the need for other medications.