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Pink Eye vs. Allergies: How to Tell the Difference

Updated June 18, 2026 · 4 min read · Minor Ailments

Red, watery, irritated eyes can come from a lot of things — but the two most common are pink eye (conjunctivitis) and eye allergies. They look almost identical, yet the right treatment is completely different. Here's how our pharmacist tells them apart, and why guessing wrong can keep you uncomfortable for days longer than you need to be.

Why it matters which one you have

Reaching for antibiotic drops when the problem is allergies won't help at all — and using a soothing antihistamine drop won't clear a bacterial infection. Both are minor ailments an Ontario pharmacist can assess and prescribe for, so a two-minute conversation at the counter can get you on the correct treatment the same day, without a doctor's appointment.

The tell-tale signs

It's more likely allergies if…

• Both eyes are affected at once.
• The main feeling is itch — allergic eyes are itchy more than anything.
• The discharge is clear and watery, not thick.
• You also have a runny nose, sneezing, or a tickly throat.
• It flares with pollen, dust, pets, or seasons and comes and goes.

It's more likely pink eye (infectious conjunctivitis) if…

• It often starts in one eye and may spread to the other.
• There's thick yellow or green discharge, especially if your lashes are crusted or stuck shut in the morning.
• The feeling is more gritty or burning than itchy.
• Someone close to you recently had it — bacterial and viral pink eye are contagious.

How each one is treated

Eye allergies usually settle with antihistamine or mast-cell-stabilizer eye drops, avoiding the trigger, and cool compresses. Bacterial pink eye may need antibiotic drops or ointment. Viral pink eye — the most common kind — often clears on its own in a week or two with comfort measures, since antibiotics don't help a virus. The trick is knowing which you have, and that's exactly what the assessment sorts out.

When to see a doctor or go to urgent care

Some eye symptoms point to something more serious. Please seek in-person medical care promptly if you have changes in vision, eye pain, sensitivity to light, a recent eye injury, or symptoms in a newborn, or if you wear contact lenses and develop a red, painful eye. Our pharmacist will also refer you on if your case needs a physician.

Get it checked at our St. Clair West pharmacy

You don't need to book a doctor or wait at a walk-in clinic. Walk in to St. Clair Drug Mart Pharmacy at 1203 St. Clair Ave W, and our pharmacist will look at your symptoms, tell you which condition you're dealing with, and start the right treatment — often in a single visit.

This article is general information, not medical advice. Speak with our pharmacist or your doctor about your specific situation.