Conjunctivitis is an inflammation of the thin, clear tissue (the conjunctiva) that covers the white part of your eye and lines the inside of your eyelids, and it’s commonly called “pink eye.”

What is conjunctivitis?

  • The conjunctiva is a clear layer over the white of the eye and inside the eyelids.
  • When it becomes inflamed or infected, blood vessels swell and the eye looks red or pink, often with irritation or discharge.
  • It is one of the most common causes of a “red eye” seen in clinics and emergency rooms.

Main causes

Conjunctivitis isn’t just one disease; it’s a group of problems that all inflame the same tissue.

  • Viral infections (often the classic, highly contagious “pink eye,” especially in children).
  • Bacterial infections (can cause more pus-like discharge; some types in newborns or adults can be serious if not treated).
  • Allergies (pollen, dust, pet dander, cosmetics; typically very itchy, often both eyes).
  • Irritants/chemicals (chlorine in pools, smoke, fumes, or other substances that irritate the eye surface).
  • Dryness or other noninfectious triggers can also inflame the conjunctiva.

Typical symptoms

  • Red or pink-looking eye (or both eyes).
  • Watery, mucous, or pus-like discharge, sometimes making eyelids stick together when you wake up.
  • Gritty feeling, burning, or mild pain in the eye.
  • Itchy eyes, especially in allergic conjunctivitis.
  • Sometimes mild swelling of eyelids and sensitivity to light.

If there is severe pain, major vision change, or intense light sensitivity, that can indicate a more serious problem and needs urgent medical care.

Is it contagious?

  • Viral and many bacterial forms are contagious and can spread easily, particularly in schools and daycare.
  • Allergic and purely chemical/irritant conjunctivitis are not contagious.

Common spread routes include touching your eyes with contaminated hands, sharing towels or cosmetics, or close contact with an infected person.

Basic treatment ideas (general info, not personal medical advice)

  • Viral conjunctivitis: Often clears on its own; treatment focuses on comfort (cool compresses, artificial tears, hygiene). Antibiotic drops do not help viruses.
  • Bacterial conjunctivitis: Sometimes treated with antibiotic eye drops or ointments, especially if discharge is heavy or symptoms are significant.
  • Allergic conjunctivitis: Managed by avoiding triggers where possible and using allergy eye drops (antihistamines, mast-cell stabilizers) or other anti-inflammatory drops as advised by a clinician.
  • Chemical/irritant conjunctivitis: Rinsing the eye and avoiding the irritant are key; severe chemical exposures are emergencies.

Always see a health professional if you have eye pain, vision changes, symptoms in a newborn, or if redness and discharge don’t improve, because some serious eye conditions can look similar.

Quick “at a glance” table

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Type Key triggers Typical features Contagious?
Viral conjunctivitis Cold/respiratory viruses, close contact with infected people.Red, watery eyes, burning or gritty feeling, often starts in one eye then spreads.Yes, often highly contagious.
Bacterial conjunctivitis Bacteria on eye surface or from contact, sometimes sexually transmitted bacteria or birth canal in newborns.Thick discharge, crusted lashes, redness; lids may stick together.Yes.
Allergic conjunctivitis Pollen, dust, pets, cosmetics, other allergens.Very itchy, watery or stringy discharge, often both eyes, often seasonal.No.
Chemical/irritant conjunctivitis Chlorine, smoke, fumes, other irritants.Red, burning, watery eyes after exposure.No.

Brief, story-style example

Imagine you wake up with one eye stuck shut, feeling sandy and looking bright pink in the mirror. By mid-morning it’s watering and you notice a bit of yellowish gunk in the corner. A family member had a “red eye” last week. That picture fits a very common form of conjunctivitis, where the inflamed conjunctiva makes the eye look red and irritated, and germs or irritants determine which specific type it is.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.