👁️ Conjunctivitis (Pink Eye): Symptoms, Causes & How to Treat It

Waking up with one or both eyes stuck shut, red, and irritated is the classic sign of conjunctivitis, commonly called "pink eye." It is an inflammation of the conjunctiva — the thin, transparent membrane that covers the white of the eye and lines the inner eyelids. Most cases are caused by viruses, are highly contagious, and spread rapidly through households, schools, and workplaces. Dr. Ravi Sishir Reddy explains the different types of conjunctivitis, how to tell them apart, the best treatments, and how to prevent infecting others.

1. What Is Conjunctivitis (Pink Eye)?

Conjunctivitis occurs when the conjunctiva becomes inflamed. This causes the tiny blood vessels in the conjunctiva to dilate, giving the eye a pink or red appearance. The three main types are:

• Viral conjunctivitis: The most common form in adults. It is usually caused by adenoviruses and often accompanies or follows a cold, sore throat, or upper respiratory infection. It is extremely contagious and spreads through direct contact with eye secretions or contaminated surfaces.
• Bacterial conjunctivitis: Caused by bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, or Haemophilus influenzae. It produces a thicker, pus‑like discharge and can affect one or both eyes. It is also contagious but responds well to antibiotic eye drops.
• Allergic conjunctivitis: Not an infection but an allergic reaction to pollen, dust mites, pet dander, or mould. It often occurs seasonally or after exposure to an allergen and is associated with intense itching, watery discharge, and often sneezing and nasal symptoms. It is not contagious.

Irritant conjunctivitis (from chemicals, smoke, or contact lenses) is another less common form. Dr. Reddy notes that distinguishing between viral and bacterial conjunctivitis based on symptoms alone can be difficult, but some key features help guide treatment.

2. Viral vs. Bacterial vs. Allergic Conjunctivitis

Symptom	Viral	Bacterial	Allergic
Itching	Mild to moderate	Mild	Severe
Redness	Generalised, pink	Generalised, deep red	Generalised, pink
Discharge	Watery, clear	Thick, yellow‑green pus	Watery, stringy mucus
Eyelid sticking	Often stuck in the morning	Frequently stuck; crusting on lashes	Rare
Tearing	Moderate	Moderate	Profuse
Associated symptoms	Cold, sore throat, fever; lymph node in front of ear may be swollen	Often only the eye is affected	Sneezing, runny nose, itchy nose
Which eye first?	Often one eye, then spreads to the other	One or both	Both eyes simultaneously
Contagious?	Highly contagious	Contagious	Not contagious

A helpful rule of thumb: if the discharge is thick, yellow‑green, and causes the eyelids to crust over, it is more likely to be bacterial. If the discharge is watery, and there is a tender lymph node just in front of the ear (preauricular lymphadenopathy), it is probably viral. If the eyes are intensely itchy and both are affected, with a history of allergies, it is likely allergic.

3. How Is Conjunctivitis Diagnosed?

Most cases of conjunctivitis are diagnosed clinically based on the history and the appearance of the eye. A doctor using a slit lamp (a specialised magnifying microscope) can examine the conjunctiva, cornea, and anterior chamber in detail. In most routine cases, laboratory tests are not needed. However, if the conjunctivitis is severe, recurrent, or not responding to treatment, your doctor may take a swab of the discharge for culture and sensitivity to identify the specific bacteria and determine the most effective antibiotic. In suspected viral conjunctivitis, a rapid adenovirus test may be performed if available.

Dr. Reddy emphasises that red eye is not always conjunctivitis. More serious conditions — such as acute angle‑closure glaucoma, iritis (uveitis), or a corneal ulcer — can also cause a red, painful eye and can lead to permanent vision loss if misdiagnosed. These are usually accompanied by moderate to severe pain, significantly blurred vision, and sensitivity to light (photophobia). If you have these symptoms, do not assume it is just pink eye — see an ophthalmologist immediately.

4. How to Treat Conjunctivitis

Treatment depends on the cause:

Viral Conjunctivitis

There is no specific antiviral for most viral conjunctivitis. It is self‑limiting and usually resolves in 7‑14 days. Management focuses on symptom relief and preventing spread:

• Cold compresses over the closed eyelids for 10‑15 minutes, several times a day, provide soothing relief.
• Artificial tears (lubricating eye drops) relieve dryness and irritation.
• Avoid touching or rubbing the eyes.
• Antibiotic drops do not help viral conjunctivitis and should not be used unless a bacterial infection is also present.
• In severe cases caused by herpes simplex virus, antiviral eye drops or oral antivirals may be prescribed by an ophthalmologist.

Bacterial Conjunctivitis

While many mild bacterial conjunctivitis cases improve on their own, antibiotic eye drops or ointment can speed recovery and reduce contagiousness. Common options include:

• Chloramphenicol, moxifloxacin, tobramycin, or erythromycin eye drops or ointment, used 3‑4 times a day for 5‑7 days.
• An ointment is often preferred at night because it provides longer contact time and prevents the eyelids from sticking shut in the morning. Drops are used during the day.
• Improvement is usually seen within 24‑48 hours. It is important to complete the full course to ensure the infection is fully cleared.
• Contact lens wearers should stop wearing their lenses immediately and discard the current pair and the lens case. They should use glasses until the infection has completely resolved and the eye is no longer red or painful.

Allergic Conjunctivitis

• Avoid the allergen whenever possible.
• Cold compresses and lubricating artificial tears provide relief.
• Antihistamine eye drops (olopatadine, ketotifen) or mast cell stabiliser drops (sodium cromoglycate) reduce itching and redness.
• Oral antihistamines (cetirizine, loratadine) can help if both eyes and nasal symptoms are present.
• Severe cases may require a short course of corticosteroid eye drops prescribed by an eye specialist.

5. How to Stop Conjunctivitis from Spreading

Viral and bacterial conjunctivitis are very contagious. Dr. Reddy advises strict hygiene to protect others and to avoid reinfecting yourself:

• Wash your hands frequently with soap and water, especially before and after touching your eyes or applying drops.
• Avoid touching or rubbing your eyes.
• Do not share towels, washcloths, pillows, or eye makeup. Use a separate towel for your face and change it daily.
• Wash pillowcases, towels, and face cloths in hot water with detergent.
• Throw away eye makeup (mascara, eyeliner) that was used just before or during the infection, as it can be contaminated.
• Clean your glasses regularly.
• Stay home from work or school until the discharge has resolved and the eye is no longer red, or for at least 24 hours after starting antibiotic drops for bacterial conjunctivitis.
• Disinfect surfaces that are frequently touched (doorknobs, keyboards, phones).

6. When to See a Doctor or Eye Specialist

Most conjunctivitis is mild and resolves without complications, but seek medical attention if you experience:

• Moderate to severe eye pain — not just irritation or itchiness.
• Significant sensitivity to light (photophobia).
• Blurred vision that does not clear with blinking or wiping away discharge.
• Intense redness in one eye, especially with a fixed, dilated pupil — could indicate acute glaucoma.
• Symptoms that worsen or do not improve after 3‑5 days of treatment.
• A white spot or ulcer on the cornea (the clear part of the eye) — this is a medical emergency.
• A weakened immune system — conjunctivitis can be more severe and atypical.
• Recent eye surgery or trauma.
• Newborns with eye discharge — this requires immediate paediatric evaluation to rule out serious infections.