Q I have had an eye irritation for about eight years but am not sure if it is due to an allergy or something else.

The initial feeling is one of discomfort and within minutes, my eyes become red and swollen or puffy.

The puffiness is more apparent in the lower eyebag. This often occurs in my right eye.

The swelling can happen at any time of the day or even while I am asleep.

A doctor has prescribed antibiotics and eye drops while an eye specialist has said I have no major eye problems.

However, the condition is a source of embarrassment as my eyes can swell within minutes.

A From the symptoms you have described, it appears to be one of two possible conditions: allergic conjunctivitis or severe dry eyes with angioedema.

Allergic conjunctivitis is an inflammation of the conjunctiva (the clear membrane that covers the white of the eye inside the eyelid) due to an allergic reaction.

It can be caused by factors such as viruses, bacteria, irritating substances (like shampoo, dirt, smoke and pool chlorine), sexually transmitted diseases, or allergens (substances which cause allergies).

When your eyes are exposed to something you are allergic to, your body's immune system responds by releasing histamine, which causes the blood vessels in the conjunctiva to swell.

As a result, the eyes redden quickly, accompanied by itching and tearing. Some easy home-care methods to relieve this discomfort include applying cool compresses to the eyes or taking oral antihistamines which are easily available at local pharmacies.

In more severe cases where home-care measures do not work, patients can go to an ophthalmologist for further treatment.

These include applying antihistamine or anti-inflammatory eye drops; the application of mild topical eye steroid preparations directly on the surface of the eye for severe reactions; or the use of eye drops that can prevent mast cells (certain white blood cells) from releasing histamine.

Severe dry eyes with angioedema could be the other possible reason for your condition.

This is a swelling similar to hives, but the swelling is beneath the skin rather than on the surface.

The hives are called welts, which are painful and may be itchy and usually occur around the eyes and lips but may also be found on the hands, feet and throat.

Similar to allergic conjunctivitis, angioedema may be caused by an allergic reaction. During the reaction, histamine and other chemicals are released into the bloodstream. It can also happen any time during the day.

However, for patients with dry eyes, the reaction tends to get worse after excessive close-up tasks like looking at a computer screen or watching TV, or upon waking up in the morning.

Similar to allergic conjunctivitis, the home-care methods I mentioned earlier can be applied.

However, with dry eyes, you could also try to relieve the discomfort with lubricant eye drops.

For both these conditions, although both eyes may be affected concurrently, it is possible that only one eye gets affected. Also, those who have asthma or eczema tend to be more hypersensitive and prone to these conditions.

In your case, where your right eye is the one usually affected, you should do an eye check to rule out any rare eye conditions, such as vascular tumours, that can cause sudden swelling in one eye over the other when both are under strain.

Dr Julian Theng

Dr Julian Theng is an ophthalmologist at East Shore Hospital

This article was first published in Mind Your Body, The Straits Times.