Is your red eye contagious or just an allergy? Here is how to tell.

Health · Published 3 October 2026 Swipe more like this →

In short: Conjunctivitis, or pink eye, turns your eyes red and gritty, but not all cases are the same. While some forms spread easily through touch, others are merely allergic reactions to pollen or pets. Knowing the difference is key to managing symptoms and preventing the infection from reaching others.

Conjunctivitis is defined by the inflammation of the conjunctiva, the clear layer covering the white of the eye and inner eyelid. Symptoms typically include redness, burning, itching, and a gritty sensation. While often affecting both eyes, the condition can begin in one and spread to the other. The nature of the discharge—watery versus sticky pus—is a primary indicator of whether the condition is contagious. Sticky, pus-producing discharge and a gritty feeling are hallmarks of infectious cases, whereas allergic conjunctivitis typically presents with redness and watering but lacks the contagious element.

The underlying cause dictates the treatment path. Viral infections are the most common cause in adults, while bacterial infections predominate in children. Viral cases often resolve on their own, though bacterial infections may be shortened with antibiotic treatment. Conversely, allergic conjunctivitis is managed using antihistamines or mast cell inhibitor drops. Because some sexually transmitted infections can cause conjunctivitis, these cases require longer recovery times and specific medical attention. It is critical to avoid contact lenses until symptoms fully subside, as lenses can complicate recovery and mask underlying issues.

Preventing the spread of infectious conjunctivitis relies on rigorous hygiene. Regular handwashing, avoiding the sharing of towels or pillows, and washing linens in hot water are essential. While most cases are mild, certain warning signs necessitate urgent medical intervention. Pain in the eyes, sensitivity to light, changes in vision, or persistent symptoms lasting beyond seven days should be evaluated by a professional. For infants under 30 days old, red and sticky eyes require an immediate urgent appointment, as these symptoms can indicate more serious health concerns.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

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