Conjunctivitis (pink eye)

Conjunctivitis, commonly called pink eye, is inflammation of the conjunctiva — the thin, clear tissue covering the white of the eye and the inside of the eyelids. It causes redness, itching, discharge, and a gritty feeling. Viral and bacterial infections, allergies, and irritants are the main causes.

Viral conjunctivitis is highly contagious but usually resolves on its own. Bacterial conjunctivitis may need antibiotic drops. Allergic conjunctivitis is not contagious and responds to allergy treatment. Most cases are mild, but severe pain, light sensitivity, or vision changes require prompt evaluation to rule out more serious eye conditions.

Common symptoms include:

• Red or pink color in the white of the eye
• Itching or burning sensation
• Gritty feeling or foreign-body sensation
• Discharge — watery (often viral or allergic) or thicker yellow-green (often bacterial)
• Crusting of the eyelids or lashes, especially in the morning
• Tearing
• Swollen eyelids
• Sensitivity to light in some cases
• In allergic conjunctivitis: intense itching and often accompanying nasal allergy symptoms

Viral conjunctivitis often starts in one eye and may spread to the other; it can accompany a cold or sore throat.

Main categories:

• Viral — adenoviruses are common; highly contagious; associated with upper respiratory infections
• Bacterial — staphylococci, streptococci, Haemophilus, and others; more common in children; gonococcal and chlamydial conjunctivitis require specific urgent treatment
• Allergic — pollen, dust mites, animal dander, mold; seasonal or perennial
• Irritant — chlorine, smoke, shampoo, pollution, foreign bodies
• Other — chemical splash, systemic diseases, or reaction to eye drops or contact lenses

Risk factors include exposure to infected people (especially in schools, daycare, and households), contact-lens wear, allergies, exposure to irritants, and compromised ocular surface or immunity. Poor hand hygiene facilitates spread of infectious conjunctivitis.

Most conjunctivitis resolves without lasting problems. Potential complications include:

• Spread of infection within households or classrooms
• Keratitis (corneal involvement) with certain viruses or bacteria, which can threaten vision
• Scarring in severe or untreated neonatal conjunctivitis
• Secondary bacterial infection
• Contact-lens-related complications if lenses are worn during infection

To reduce spread and recurrence:

• Wash hands often with soap and water
• Avoid touching or rubbing the eyes
• Do not share towels, pillows, eye makeup, or eye drops
• Change pillowcases frequently during an episode
• Stay home from school or work when contagious if recommended
• Manage allergies and avoid known irritants
• Practice good contact-lens hygiene; do not wear lenses during infectious conjunctivitis

Diagnosis is usually clinical based on history and eye examination. Features that help distinguish types include discharge character, itch intensity, laterality, and associated cold or allergy symptoms. Cultures or rapid tests are reserved for severe, atypical, neonatal, or treatment-resistant cases. Slit-lamp examination may be performed when corneal involvement or alternative diagnoses are a concern.

See a clinician or eye-care professional for moderate to severe symptoms, significant discharge, vision changes, severe pain, light sensitivity, or if symptoms do not improve after a few days. Newborns with eye redness or discharge need urgent evaluation. Contact-lens wearers with red eyes should stop wearing lenses and seek care promptly.

Treatment depends on the cause:

• Viral — supportive care (cool compresses, artificial tears); usually self-limited over 1–2 weeks; antiviral therapy only for specific viruses (e.g., herpes)
• Bacterial — topical antibiotic drops or ointment when indicated; many mild cases resolve without antibiotics
• Allergic — allergen avoidance, oral or topical antihistamines, mast-cell stabilizers, and topical anti-inflammatory drops as needed
• Irritant — remove the irritant and rinse with saline or clean water; further care depending on the chemical
• Gonococcal / chlamydial — systemic antibiotics and urgent specialist care

Steroid eye drops should be used only under clinician supervision because they can worsen certain infections.

Helpful measures:

• Apply cool or warm compresses (clean cloth each time; separate for each eye if both are affected)
• Use preservative-free artificial tears for comfort
• Clean away discharge with a clean, moist cloth
• Stop contact-lens wear until cleared by a clinician
• Discard eye makeup used during the infection
• Practice strict hand hygiene
• Do not share personal items

Bring:

• Description of symptoms, discharge, and which eye(s) are affected
• Recent colds, allergy flares, or known exposures
• Contact-lens use and hygiene habits
• List of eye drops and medicines
• Questions about contagiousness, return to school/work, and whether antibiotics are needed