Allergic Conjunctivitis: Symptoms, Causes, and Diagnosis

Redness, itching, and tearing are signs that can occur with eye allergy. They may be caused by allergic conjunctivitis — inflammation of the clear membrane that lines the eyelids and covers the white of the eye. Below: how it differs from an infection and what the doctor checks.

What allergic conjunctivitis is and what forms it has

The conjunctiva is a clear layer of tissue that lines the eyelids and covers the white of the eye. Conjunctivitis means that this membrane has become inflamed and swollen; causes include infection, an irritant, dry eyes, or allergy. The allergic form is a reaction to pollen, animal fur and dander, mold, and other substances that cause allergy.

Forms are distinguished by scenario. Allergy, for example with hay fever, causes redness and tearing. A long-lasting form is vernal conjunctivitis: it occurs with chronic allergy and asthma, more often in boys and young men, in spring and summer.

Symptoms: what eye allergy looks like

Symptoms include itching, redness, tearing, and a gritty sensation. Usually both eyes are affected. Allergy does not leave sticky pus on the eyelashes — unlike the bacterial form.

• itching and burning in the eyes;
• redness;
• tearing;
• a gritty sensation, as if a speck has gotten into the eye.

Pain, photophobia, and changes in vision are signs that require a doctor; crusts on the eyelids in the morning are more often associated with a bacterial infection.

What causes allergic conjunctivitis

The cause is contact with an allergen: pollen, animal dander and fur, mold. Tears wash away microbes and irritants and contain proteins and antibodies, so when the eyes are dry, the same exposures are tolerated worse. A similar picture is caused by chemicals, smoke, dust, and excessive contact lens wear — this is irritation, not allergy.

Allergic conjunctivitis in children and with contact lens wear

The difficulty lies elsewhere: "pink eye" in children is more often caused by a viral infection, which spreads easily in kindergarten and school. In newborns, eye infection may be caused by bacteria from the birth canal and requires immediate treatment to preserve vision.

In those who wear lenses for many years, a condition similar to vernal conjunctivitis develops; continuing to wear lenses becomes difficult. Spots on the eyelids together with symptoms give reason to suspect allergy to the lenses themselves.

Is it contagious and how long does it last

Conjunctivitis caused by allergy is not contagious. The forms with sticky pus and those in which the eyes are red and feel as if sprinkled with sand are contagious. Infectious conjunctivitis usually resolves within a couple of weeks without treatment; allergic conjunctivitis may resolve on its own when contact with the allergen stops.

Timeframes differ: one threshold is 3–4 days without improvement, another is 7 days. With either of them, an examination is needed.

How diagnosis is carried out and when a doctor is needed

The doctor examines the eyes and assesses the condition of the membrane and eyelids. If necessary, a swab is taken from the conjunctiva for analysis; there are also in-office tests for a specific virus. The distinguishing feature of the allergic form is the absence of sticky pus characteristic of a bacterial infection.

Urgent consultation with a doctor is necessary for eye pain, photophobia, changes in vision such as wavy lines or flashes, very red eyes, and also if a child younger than 30 days has red, stuck-together eyes. Swelling of the eyelids or skin around the eyes is also a reason to seek care.

Red eyes alone are not a reason to call an ambulance; 103 or 112 — for a life-threatening condition according to the general criteria for emergencies.

This material is for reference: it explains how the problem works but does not replace consultation with a doctor — the diagnosis is made during an examination.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer