Eye Allergy – How to Recognise It, What Helps and When to See an Eye Doctor

Eyes so itchy you cannot stop touching them, red, watering and slightly puffy – in spring, after dusting or after stroking the cat. This is eye allergy, known medically as allergic conjunctivitis. It is not contagious and in most cases does not threaten your sight, but it can be very wearing. The good news: once you understand what is happening in the eye and use the right treatment, most people get their symptoms well under control.

What happens in the eye

The conjunctiva is the clear membrane that covers the white of the eye and the inner surface of the eyelids. It contains immune cells called mast cells. In people prone to allergy, contact with an allergen – plant pollen, house dust mites, pet hair and saliva, mould – makes these cells release histamine and other inflammatory substances. The result comes within minutes: itching, redness, watering and swelling.

The key sign: itching

If one word sets allergy apart from other eye problems, it is itching. Other typical signs:

• Both eyes are affected, usually to the same degree.
• Redness, watering and a clear watery or stringy discharge.
• Swelling of the eyelids and sometimes of the conjunctiva itself, which looks like clear “jelly” over the white of the eye.
• A background of runny nose, sneezing or asthma.
• Worsening in certain seasons, or with obvious exposure to dust, pets or smoke.

What is not typical of allergy: real pain, strong sensitivity to light, reduced vision, only one eye affected, or a thick yellowish discharge. These point to a different problem – most often infectious conjunctivitis or a problem with the cornea – and need to be examined.

The types

Seasonal allergy – the most common form. It appears in spring and early summer, during the pollen season, and usually comes with allergic rhinitis (hay fever).

Year-round allergy – caused mainly by house dust mites, pets and mould. Symptoms are usually milder, but constant.

Forms that need follow-up by an eye doctor – less common, but important to know about:

• Vernal keratoconjunctivitis (VKC) – common in children and teenagers, especially in warm climates such as Israel’s. The itching is intense, there is a thick stringy discharge, and large bumps form on the inner surface of the upper eyelid. In some cases the cornea is affected too.
• Atopic keratoconjunctivitis (AKC) – in adults with atopic dermatitis (eczema). It is chronic and can damage the cornea.
• Reaction to contact lenses – small bumps on the inner surface of the upper eyelid, discomfort and mucus, usually in people who have worn lenses for a long time.

In these forms, over-the-counter drops are not enough, and examination and follow-up are needed.

Allergy, dryness or infection?

All three conditions can look alike, and can also occur together. Dry eye causes burning, a gritty feeling and tired eyes more than itching, and gets worse in front of screens and in air conditioning. Infectious conjunctivitis usually comes with discharge and often starts in one eye. There is also a common situation in which drops or products used around the eyes are themselves causing the reaction: preservatives in drops, creams, make-up. For the various causes of a red eye, see red eyes.

What to do at home

• Don’t rub. Rubbing releases more histamine and increases the itching – and see below on the damage to the cornea.
• A cold compress on closed eyes for a few minutes soothes the itching and swelling.
• Preservative-free lubricating drops, ideally chilled, wash allergens out of the eye.
• Reduce exposure: in pollen season, keep windows closed at peak times, wear wraparound sunglasses, and wash your face and hair when you get home. At home: wash bedding in hot water, and keep pets out of the bedroom.
• Contact lenses: during a flare-up it is better to take them out. Daily disposable lenses are usually better tolerated.

Allergy drops – how they differ

Dual-action drops – an antihistamine and a mast cell stabiliser in the same drop. They calm the itching within minutes and also reduce the next reaction, which is why they are the mainstay of treatment. Some are sold without a prescription; for the differences between products, see over-the-counter eye drops. For seasonal allergy you can start them even before the season begins.

Drops that constrict blood vessels (“anti-redness”) – whiten the eye quickly, but do not treat the allergy itself. With prolonged use they can cause rebound redness when the effect wears off, so they are suitable for short-term use only.

Anti-allergy tablets – very helpful for a runny nose and sneezing, but less effective than drops for itchy eyes, and in some people they dry the eyes out.

Steroid drops – very effective in a severe flare-up, but only under the guidance of an eye doctor, for a short time and with follow-up. Unsupervised use can raise eye pressure, speed up cataract formation and worsen infections such as herpes in the eye.

Drops that modulate the immune system – in the chronic, severe forms, such as vernal and atopic keratoconjunctivitis, the eye doctor can prescribe drops that calm the immune response over the long term and allow steroids to be reduced.

Why it matters so much not to rub

Hard, repeated eye rubbing over months and years has been linked to weakening of the cornea and to the development or worsening of keratoconus – a condition in which the cornea becomes thin and changes shape. This is one of the reasons why children and teenagers with eye allergy, and especially those with vernal keratoconjunctivitis, need good treatment and follow-up: controlling the itch reduces the urge to rub. If you have a child at home who rubs their eyes constantly, or whose glasses prescription changes quickly, it is worth having the cornea checked too.

When to see an eye doctor

• Eye pain, strong sensitivity to light or reduced vision.
• Only one eye affected, or a thick yellowish discharge.
• Symptoms that do not settle after a week or two of home care and drops.
• Children with intense, prolonged itching, a thick stringy discharge or constant eye rubbing.
• Eczema on the eyelid skin together with eye symptoms.
• Anyone who needs steroid drops, or has used them in the past without follow-up.
• Contact lens wearers with a red, painful eye – here the concern is contact lens keratitis, not allergy.

An examination with Prof. Michael Mimouni

Prof. Michael Mimouni, Director of the Cornea Unit at Rambam, sees patients with corneal and ocular surface problems – including eye allergy, dry eye and eyelid inflammation – at his clinics in Herzliya Pituach and Haifa. During a slit-lamp examination we will check the conjunctiva and the inner surface of the eyelids, make sure the cornea is healthy, and put together a treatment plan suited to the type of allergy and the season. Get in touch to book an appointment.

The information on this page is general and is not a substitute for an examination and personal medical advice. Diagnosis and treatment decisions are made only after a full eye examination. Do not use steroid drops without the guidance of an eye doctor.