Pink eye is one of the most familiar eye conditions in the world. The medical term, conjunctivitis, refers to inflammation of the thin transparent membrane that covers the white of the eye and lines the inner eyelid. It can arise from infection, allergy, or irritation, and although most cases resolve on their own, knowing which type you are dealing with shapes both treatment and how cautious you need to be around other people.

Viral Conjunctivitis

Viruses, particularly adenoviruses, cause the majority of contagious pink eye cases. Symptoms include watery discharge, redness, a gritty sensation, and often a recent cold or sore throat. Viral conjunctivitis is highly contagious for up to two weeks and spreads through droplets, contaminated hands, and shared towels. Treatment is supportive: cool compresses, artificial tears, and meticulous hand hygiene.

Bacterial Conjunctivitis

Bacterial cases tend to produce thicker, yellow-green discharge that mats the lashes shut overnight. They respond well to topical antibiotic drops or ointment, with most patients improving within a few days. Newborns, contact lens wearers, and people with significant pain or vision change deserve prompt medical evaluation, since some bacterial strains can damage the cornea.

Allergic Conjunctivitis

Allergic conjunctivitis is not contagious. It affects both eyes simultaneously, produces intense itching rather than burning, and is usually accompanied by sneezing or nasal congestion. Triggers include pollen, animal dander, and dust mites. Antihistamine eye drops, oral antihistamines, and cool compresses provide reliable relief, and identifying the trigger helps prevent repeat episodes.

Irritant and Chemical Causes

Smoke, chlorine, cosmetics, and air pollution can all inflame the conjunctiva. Symptoms resemble mild infection but resolve quickly once exposure ends. The Mayo Clinic provides a helpful overview of the different forms at mayoclinic.org, including when to seek urgent care for chemical splashes that require immediate flushing with water.

Preventing Spread at Home and School

Because viral and bacterial forms spread easily, sensible precautions matter. Wash hands frequently, avoid touching the eyes, do not share pillowcases or makeup, and replace contact lens cases. Schools and workplaces often request a day or two at home until obvious discharge subsides. Disinfecting doorknobs and phone screens reduces household transmission considerably.

When to See a Professional

Most pink eye clears within one to two weeks. Worsening pain, sensitivity to light, blurred vision that does not clear with blinking, or symptoms lasting more than two weeks all warrant a visit to an eye care provider. Contact lens wearers should remove their lenses at the first sign of redness and consult a clinician before resuming wear, as a corneal ulcer can mimic conjunctivitis in its earliest stage.