Conjunctivitis (Pink Eye)

Conjunctivitis or pink eye, as it is commonly called, is an inflammation or swelling in the conjunctiva, the thin membrane that covers the white area of your eyeball and inner eyelid.

Once the blood vessels in the conjunctiva become inflamed, it produces the pink or red color that’s commonly linked with conjunctivitis.

While some forms of conjunctivitis can be highly contagious, others may be triggered by exposure to harsh chemicals or by an allergy. Symptoms may last for a prolonged period and include tearing, redness, itching, and more.

What are the causes?

Conjunctivitis is a fairly common condition with a number of causes. These causes can be grouped into three categories: allergic conjunctivitis, infectious conjunctivitis, and chemical conjunctivitis.

Allergic conjunctivitis

Pink eye can be triggered by allergens, or when foreign bodies find their way into your eyes. It is usually itchy.

Allergens like pollen or dust can trigger your body to create more histamine, which causes inflammation as your body responds to what it thinks is an infection. In turn, it causes pink eye in one or both eyes. Some common causes of allergic conjunctivitis include

  • Food allergies
  • Seasonal allergies
  • Contact dermatitis of the eyelids (often as a result of rubbing the eyes)

Infectious conjunctivitis

This type of conjunctivitis is highly contagious and is caused by viruses and bacteria. Bacterial conjunctivitis is commonly caused by staphylococcus or streptococcus, the bacteria responsible for staph infections or strep throat.

They are usually transmitted by sharing eye makeup or touching your eyes with unclean hands. Viral conjunctivitis, on the other hand, is usually caused by the same viruses responsible for the common cold.

Some common infectious conjunctivitis includes:

  • Keratoconjunctivitis – what most people refer to as pink eyes
  • Ophthalmia neonatorum – a serious type that can also affect babies as they pass through the birth canal

Chemical conjunctivitis

Also known as toxic conjunctivitis, this form of pink eyes can be triggered by anything in the environment that injures or irritates the eyes. Some common causes include

  • Smoke
  • Fumes
  • Acid exposure
  • Over-chlorinated pools

Rinsing your eyes with flowing water is a simple and effective way to stop a chemical irritant from causing pink eyes.

What are the symptoms?

Pink eye symptoms are a result of the immune system’s response to an infection or irritant with inflammation. This involves the expansion of blood vessels to create room for larger cells to access an injured area.

If there is an infection, the build-up of dead viruses or bacteria and dead white blood cells can lead to the formation of pus.

Depending on the cause, people with conjunctivitis may experience some or all of the following symptoms and more. Speak with your physician about treatment if you experience any of the following.

  • Burning or itchy eyes
  • Pink or red discoloration in one or both eyes
  • Swollen eyelids
  • Blurred vision
  • Excessive tearing
  • Gritty feeling in the affected eye
  • Thick or watery discharge that forms a crust on your eyes at night
  • Increased sensitivity to light

If you have pink eyes, it is essential to pay attention to your symptoms as the condition can be transferred to others up to two weeks after it develops.

How is the condition diagnosed?

Diagnosing pink eye isn’t difficult. First of all, your doctor will want to determine whether the cause is allergic, infectious, or toxic.

To do this, your doctor will simply ask you a few questions and examine whether:

  • There is visible discharge ( usually a sign of an infection)
  • One of both eyes are affected ( as infections usually affect only one eye)
  • The discharge is thin or thick (this can help differentiate a bacterial or viral infection)
  • There is bleeding in the affected eye (mostly common with viral infection)
  • There are allergy symptoms (such as allergic rhinitis or hives)
  • There are swollen nymph nodes (a clear indication of an infection)

Your doctor may also ask you if you’re experiencing symptoms of asthma, hay fever, or the common cold.

Depending on the severity and type of symptoms, your physician may take a fluid or tear sample from your conjunctiva and send it to a lab for further testing to help pinpoint an infectious case, if present. Other tests may include

  • Rapid screening (to confirm Keratoconjunctivitis – EKC)
  • A fluorescent eye stain (used to look for abrasions or evidence of a lesion or sore)

What are the treatments for pink eye?

Conjunctivitis (Pink Eye)

The treatment of pink eye depends on the underlying cause. If a chemical irritant caused your pink eye, there’s a good chance that it will clear up on its own in a few days. If it was caused by an allergen, bacterium, or virus, they might require oral medications or eye drops.

Here are a few treatment options

Allergic conjunctivitis

If your pink eye was caused by an allergen, your physician might likely prescribe an antihistamine to stop the inflammation. Some common antihistamines available in over-the-counter medications include Loratadine and diphenhydramine.

They are useful in clearing allergic symptoms and may help clear allergic conjunctivitis. Other treatments include anti-inflammatory eye drops or antihistamine eye drops.

Bacterial conjunctivitis

To treat conjunctivitis caused by a bacterium, your doctor will most likely recommend an antibiotic. While adults prefer eye drops, ointment might be suitable for children as it’s easier to apply.

With the use of antibiotic medication, you may begin to clear out in a few days.

Viral conjunctivitis

Unfortunately, there is no treatment available for viral conjunctivitis. As with common cold and other viral infections, the illness just has to run its course and will probably clear out in on its own in 7 to 10 days.

If you experience severe pain or discomfort, steroid eye drops may help soothe your symptoms.

How can you prevent pink eye?

One of the best ways to prevent and stop the transmission of conjunctivitis is by practicing good hygiene. Wash your hands often and thoroughly, and try to avoid touching your eyes with dirty hands. Only use clean towels and tissues to wipe your eyes and face.

Make sure not to share your cosmetics with other people, especially mascara or eyeliner. Also, make it a habit to change and wash your pillowcases frequently.

If your doctor thinks that your contact lenses are contributing to your condition, they may recommend switching to another type of disinfection solution or contact lens.

They may also recommend cleaning or replacing your contact lenses more frequently, or that you stop wearing contact lenses till further notice – or at least until your eye heals. Avoiding decorative contact lenses or poorly fitted contact lenses may also reduce your risk of a pink eye.

How to prevent the transmission of the illness

If you already have conjunctivitis, you can keep your family and friends safe by observing the following:

  • Avoid sharing washcloths and towels
  • Wash your hand frequently
  • Change your washcloth and towel daily
  • Once your infection clears, replace your eye cosmetics
  • Follow your physician’s advice on contact lens care

If your child develops pink eye, it is best they skip school for at least 24 hours after they start treatment, and till the symptoms have fully resolved, so they don’t transmit the pink eye to others.

Also, observe the preventive steps if you are infected. If you have bacterial conjunctivitis, you should avoid going to work until you have had at least 24 hours of treatment with an eye drop or any other topical medication.

If your infection is viral, you may need to call out or work from home until the illness has run its course. If you go back to work early, try as much as possible not to touch your eye, as this can transmit the discharge to doorknobs, keyboards, and other objects that your co-workers may come in contact with.

Avoid using an eye patch, as this can help the bacteria grow. Instead, carry antiseptic wipes to clean surfaces and avoid shaking hands with clients and colleagues.

Bottom line

Pink eye is usually not a serious eye infection, but it can develop into a severe condition if left untreated. While many forms of conjunctivitis can be treated by a pediatrician or a general practitioner, severe cases – or those that refuse to respond to treatment – should be handled by an ophthalmologist.


  • Conjunctivitis: A Systematic Review of Diagnosis and Treatment – NCBI
  • Conjunctivitis – AOA
  • Conjunctivitis: Overview – NCBI
  • Conjunctivitis (Pink Eye) – CDC
  • Pink eye (conjunctivitis) – MayoClinic
  • Common eye infections – NPS
  • Allergic conjunctivitis: a comprehensive review of the literature – BMC