Pink Eye Causes

There are three leading causes of pink eye:

• Viruses
• Bacteria
• Allergens or irritants

A fungus or parasite may cause pink eye, but it is rare. Let’s take a closer look at each leading cause of pink eye.

Viral Conjunctivitis

Viral pink eye is the most common type, accounting for about 75 percent of cases. Viral conjunctivitis is highly contagious even before symptoms develop and remains contagious while symptoms are present.

Several different viruses can cause pink eye, including:

• Adenovirus is the most common cause of viral conjunctivitis and the virus that causes the common cold.
• COVID-19 virus can cause pink eye.
• Epstein-Barr virus, which also causes infectious mononucleosis.
• Herpes simplex virus, which can also cause painful blisters or ulcers.
• Varicella-zoster virus, which also causes chickenpox and shingles.

Bacterial Conjunctivitis

Pink eye caused by bacteria is less common than viral pink eye. Bacterial pink eye is very contagious from the time symptoms appear until they resolve or until 24 hours after starting antibiotics.

The most common bacteria that cause pink eye include:

• Chlamydia trachomatis, which is a sexually transmitted disease (STD) that can be passed from mom to baby through the birth canal during childbirth.
• Haemophilus influenzae is most common in babies and toddlers.
• Neisseria gonorrhoeae is another STD that can be passed from mom to baby through the birth canal during childbirth.
• Moraxella catarrhalis is a common cause of inner ear and sinus infections.
• Staphylococcus aureus is a bacteria commonly carried in the nose and on the skin of healthy people.
• Streptococcus pneumoniae, which is the leading cause of community-acquired pneumonia.

Allergic Conjunctivitis

Pink eye from allergens and irritants is not contagious. The most common allergens and irritants that cause pink eye include:

• Chlorine or other pool chemicals
• Dander from pets
• Dust mites
• Molds
• Pollen from grass, plants, trees, and weeds

Pink Eye Symptoms

Whether your kiddo’s pink eye is viral, bacterial, or from an allergen, there are some similar signs and symptoms:

• Crusting of their eyelashes or eyelids, especially in the morning when they wake
• Eye discharge, which may be green, white, or yellow
• Irritation and itching of the eye
• Pink or redness in the white of the eye
• Swelling of the eyelids

Your little one may have more specific symptoms depending on the type of pink eye they have. For example:

Viral Pink Eye –

• Has a watery eye discharge.
• Generally starts with one eye and spreads to the other eye within a day or two.
• May occur with other viral illnesses such as a cold, flu, or respiratory infection.

Bacterial Pink Eye –  

• Has a thicker eye discharge.
• May occur with an ear or sinus infection.

Allergic Pink Eye –

• Affects both eyes.
• Causes intense irritation and itching.
• May occur with other allergy symptoms such as asthma, sneezing, or sore throat.

You should call your child’s healthcare provider or eye doctor if your child is a newborn or if your little one has:

• A weakened immune system from an underlying health condition
• Blurred vision
• Eye pain
• Fever
• Intense eye redness
• Light sensitivity
• Symptoms that worsen or do not start to improve after a week of home treatment or after two to three days of medical treatment

Pink Eye Prevention

Viral and bacterial pink eye are highly contagious. Even if your kiddo already has it, you’ll want to take note of these prevention tips to keep them from getting it again. You and your child should:

• Wash your hands! Good hygiene can prevent the spread of most bacteria and viruses. You should wash your hands after applying compresses or eye drops, and your child should wash their hands multiple times a day. Wash your hands with warm water and soap, or use an alcohol-based hand sanitizer if soap and water are unavailable.
• Avoid touching your eyes, face, mouth, or nose.
• Clean frequently touched surfaces in your home, like countertops, doorknobs, faucet handles, and toilets.
• Cough and sneeze into your elbow or sleeve, as some viruses and bacteria that cause pink eye can be transmitted through coughing and sneezing.
• Do not share contact lenses, eye drops, eyeglasses, or eye makeup with others.
• Encourage your child not to touch their friends’ faces.
• Replace or thoroughly disinfect contact lenses that may have been worn as pink eye symptoms developed.
• Stay home from school as long as symptoms are present.
• Stay up to date with all recommended vaccines. Many vaccines can help prevent some of the viral and bacterial causes of pink eye, such as:
  • Chickenpox
  • Haemophilus influenzae type b (Hib)
  • Measles
  • Pneumococcal
  • Rubella
  • Shingles
• Throw away any makeup that may have been worn as pink eye symptoms developed.
• Throw away any tissues used to blow your nose, cough, sneeze, or wipe your eyes immediately.
• Wash all linens such as pillowcases, sheets, towels, and washcloths used by someone with pink eye separately in hot water to prevent the spread.