Healthy Living

What Are the Causes of Conjunctivitis?

What Are the Causes of Conjunctivitis?

Key Takeaways

  • Conjunctivitis, also commonly called as “pink eye”, is an eye infection caused by either bacteria or viruses.
  • Conjunctivitis is an eye infection that is very common in children.
  • You can also develop a "pink eye" if you are exposed to certain allergens that can irritate your eyes. 

What is conjunctivitis?

Conjunctivitis, also commonly called as “pink eye”, is an eye infection caused by either bacteria or viruses. You can also develop a "pink eye" if you are exposed to certain allergens that can irritate your eyes. When you have a pink eye, the conjunctiva of your eye is inflamed. The conjunctiva is the tissue layer that lines the eyelid’s surface and covers the sclera (white part of the eye).

This eye infection is very common, especially in children. The small blood vessels in the conjunctiva can be visibly seen when they become inflamed. The inflammation is what causes the whites of your eyes to appear reddish or pink. That is why whenever we see a person who has conjunctivitis, their eyes appear to be reddish or pink. Although this kind of eye infection can be very irritating, it hardly causes vision impairment. Treating pink eye as soon as possible can help ease the discomforts. An early diagnosis of conjunctivitis is also needed to limit the spread of the infection.

Causes of Conjunctivitis

There are three causes why someone gets a pink eye. They are:

  •  bacterial infection
  •  viral infection
  •  allergic reaction

The first two are very contagious and can be easily spread at schools, workplaces, or in public transport vehicles. Usually, conjunctivitis is a minor infection, but sometimes, it can develop into a more serious condition that can affect the whole body and not just the eyes. Whether the infection is caused by allergies, viruses, or bacteria, the most common symptoms are:

  • a gritty feeling in one or both eyes
  • redness in the white part of the eye 
  • an itching and burning feeling
  • increased tear production
  • secretions and discharges from the eyes
  • swollen eyelids
  • increased light sensitivity
  • blurry vision 
  • severe pain in the eyes

Allergic Conjunctivitis

Allergic conjunctivitis happens when both of your eyes are affected by allergens such as pollen and animal dander. Your body produces immunoglobulin E (IgE) antibodies in response to these allergy-causing substances. IgE antibodies trigger mast cells, which are white blood cells that mediate inflammatory responses. Mast cells release histamine (a powerful chemical mediator) when you are exposed to allergens. The histamine released by the mast cells produce allergy symptoms, which include redness of the eyes. 

Two Types of Allergic Conjunctivitis

1. Allergic conjunctivitis - is caused by allergens such as pollen, smoke, or chlorine in the water. It is most commonly seen in people who have seasonal allergies. However, this type of conjunctivitis is not contagious.

2. Giant papillary conjunctivitis - is caused by a chronic presence of a foreign body on the eye surface. This type of eye infection is most commonly experienced by people who use contact lenses.

Infectious Conjunctivitis

  • Viral conjunctivitis - can develop after a person comes in contact with someone who coughs or sneezes, or those afflicted with sickness such as the common cold. The virus can spread in the whole body including the conjunctiva and tear ducts. Since the infection originates from a virus, treatment is not really necessary as viruses are self-limiting. However, signs and symptoms can be managed by the use of support compresses (cool or warm) and topical antihistamines to relieve itching and redness.
  • Bacterial conjunctivitis - is primarily caused by bacteria of staphylococcal or streptococcal origin. The infection can be passed through direct physical contact with someone who already has bacterial conjunctivitis. The infection can also be contracted through the sharing of contaminated towels, pillows, and eye makeup. People who use contact lenses should be very careful to use only their own lens containers and artificial tears.Bacterial conjunctivitis is regarded as the second most common cause of infectious conjunctivitis. The most common indicators of bacterial conjunctivitis are sticky mattering of your eyelids upon waking up and eye edema (excess fluid in the tissues that surround the eyes). Uncomplicated cases of bacterial conjunctivitis often resolve after 1-2 weeks.
  • Ophthalmia neonatorum - is a mild form of conjunctivitis that affects newborn babies, but since their immune system is still not highly developed, the infection can lead to a permanent damage. A newborn's eyes are susceptible to bacteria, which is normally present in the mother's birth canal. These bacteria cause no symptoms in the mother. However, the mother can pass the infection to her baby while giving birth. Thus, pregnant women have to monitor their health condition and are recommended to give birth via C-section if there is any doubt that the mother is infected with certain bacteria or viruses. This condition needs treatment without delay to preserve sight. That's why shortly after birth, an antibiotic ointment is applied to every newborn's eyes. The ointment helps in preventing eye infections.

Chemical Conjunctivitis

This type of conjunctivitis can be caused by particular irritants such as air pollution, chlorine and other chemicals in swimming pools, or by an exposure to toxic chemicals.

If you have any of these symptoms, you should visit an ophthalmologist immediately. The doctor will give you further instructions on how to manage your eye condition. You may also have to go through a laboratory test just to know if the infection has spread in the whole body. For future protection, people who once had some type of conjunctivitis have to use their own blankets, pillows and pillowcases, bath towels, and makeup. It is very important not to share contaminated things with anyone. The disease may come back later, but having an increased awareness of precautionary measures ensures that basic prevention steps have been covered.

Preventing the Spread of Pink Eye

Practicing good hygiene is clearly the best way to control the spread of conjunctivitis. Proper precautionary measures include:    

      •    not touching your infected eyes with your hands
      •    regular washing of your hands with soap and water
      •    using clean towels and washcloths
      •    not using other people's towels or washcloths
      •    changing your pillowcases often
      •    not swimming in a swimming pool
      •    throwing away eye cosmetics such as mascara
      •    not sharing personal eye care items
      •    taking a complete course of antibiotics or other medications to effectively get rid of the infection

The symptoms of conjunctivitis often resolve after 3-7 seven days. However, children who have viral conjunctivitis may remain contagious for one week or more. If your child has bacterial conjunctivitis, do not send him or her to school without proper treatment. Your child can go back to school once the redness and eye discharges subside. Consult your doctor if you have any concerns or questions about when your child can go back to school or child care facilities.