Causes and Risk Factors of Conjunctivitis
Discover the common causes and risk factors of conjunctivitis, including viral and bacterial infections, allergens, and irritants. Understand who is most at risk and how to prevent its spread effectively.
Written by Dr. Dhankecha Mayank Dineshbhai
Reviewed by Dr. Rohinipriyanka Pondugula MBBS
Last updated on 25th Aug, 2025
Introduction
Conjunctivitis, commonly known as "pink eye," is an eye condition that causes redness, irritation, and sometimes discharge. It can affect people of all ages and is usually not serious, but it can be uncomfortable and contagious. Understanding what causes conjunctivitis and the factors that increase your risk can help you prevent it or seek timely treatment.
What Causes Conjunctivitis?
Conjunctivitis occurs when the thin, clear tissue covering the white part of the eye (conjunctiva) becomes inflamed. The main causes include:
1. Viral Conjunctivitis
Cause: Viruses, such as the common cold or adenovirus.
How it spreads: Highly contagious through direct contact with infected eye secretions or respiratory droplets (sneezing, coughing).
Symptoms: Watery discharge, redness, itching, and often affects one eye before spreading to the other.
2. Bacterial Conjunctivitis
Cause: Bacteria like Staphylococcus aureus, Streptococcus pneumoniae, or Haemophilus influenzae.
How it spreads: Touching eyes with dirty hands, sharing contaminated towels, or makeup.
Symptoms: Thick yellow or green discharge, crusting of eyelids (especially after sleep), and redness.
3. Allergic Conjunctivitis
Cause: Allergens like pollen, dust mites, pet dander, or smoke.
How it spreads: Not contagious; triggered by exposure to allergens.
Symptoms: Itchy, watery eyes, swelling, and often occurs with other allergy symptoms (sneezing, runny nose).
4. Irritant (Chemical) Conjunctivitis
Cause: Exposure to irritants like chlorine (in swimming pools), smoke, air pollution, or harsh chemicals.
How it spreads: Not contagious; caused by direct irritation.
Symptoms: Burning sensation, redness, and excessive tearing.
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Who is at Risk of Conjunctivitis?
Certain factors increase the likelihood of developing conjunctivitis:
1. Age
Children are more prone due to frequent exposure in schools and daycare centres.
Older adults may have weaker immune systems, making them susceptible to infections.
2. Weakened Immunity
People with conditions like diabetes, HIV, or those undergoing chemotherapy are at higher risk.
3. Seasonal Allergies
Those with hay fever or allergic rhinitis are more likely to develop allergic conjunctivitis during high-pollen seasons.
4. Contact Lens Wearers
Improper lens hygiene can lead to bacterial or viral infections.
Sleeping with lenses increases the risk of irritation and infection.
5. Exposure to Infected Individuals
Being around someone with viral or bacterial conjunctivitis raises the risk of catching it.
6. Environmental Factors
Living in polluted areas or working in dusty/smoky environments can trigger irritant conjunctivitis.
How Can You Reduce the Risk?
Here’s how you can reduce the risk of conjunctivitis:
1. Practice Good Hygiene
Wash hands frequently with soap and water.
Avoid touching or rubbing your eyes.
Do not share towels, makeup, or eye drops with others.
2. Protect Your Eyes
Wear sunglasses to shield against allergens and irritants.
Use goggles while swimming to prevent chlorine irritation.
3. Manage Allergies
Keep windows closed during high pollen seasons.
Use antihistamine eye drops (after consulting a doctor).
4. Proper Contact Lens Care
Clean and store lenses as directed.
Replace them on schedule and avoid sleeping with them.
5. Avoid Contagious Spread
If infected, stay home until symptoms improve (especially for viral/bacterial types).
Disinfect surfaces like doorknobs and phones regularly.
When to See a Doctor?
Most cases of conjunctivitis resolve on their own, but seek medical help if:
Symptoms worsen or last more than a week.
There is severe pain, blurred vision, or sensitivity to light.
The eye produces thick pus-like discharge (possible bacterial infection).
If you suspect conjunctivitis, you can consult an eye specialist on Apollo 24|7 for proper diagnosis and treatment.
Conclusion
Conjunctivitis is common but manageable with the right precautions. Knowing its causes and risk factors helps in prevention and timely care. Simple hygiene practices and avoiding irritants can go a long way in keeping your eyes healthy.
If you experience persistent symptoms, don’t hesitate to book an online consultation or schedule an eye test through Apollo 24|7 for expert advice. Stay informed, stay safe!
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Consult Top Ophthalmologists
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Consult Top Eye Surgeon
Dr. Smriti Nagpal
Ophthalmologist
13 Years • MBBS , MS (Ophthalmology)
New Delhi
Sunshine mediclinic, New Delhi
Dr. S Venkateswaran
Ophthalmologist
35 Years • MBBS, PGD (OPTHALMOLOGY)
Tiruvannamalai
Shiva Eye And General Hospital, Tiruvannamalai
Dr. Anupa Gulati
Ophthalmologist
25 Years • MBBS, Dip in Ophthalmology
New Delhi
Visitech Eye Centre Green Park, New Delhi
Dr. Mridula V Amarnath
Ophthalmologist
12 Years • MBBS,MS (Opthalomology)
Bengaluru
Apollo Medical Center, Marathahalli, Bengaluru
Dr. Smita Gaurav Gujarathi
Ophthalmologist
4 Years • MBBS DNB (Opthal)
Nashik
Apollo Hospitals Nashik, Nashik
