In this blog post we will be discussing what “pink eye” is. We’ll discuss what conjunctivitis means and whether it is a non-contagious conjunctivitis/non-infectious conjunctivitis. We will answer the question: does pink eye require antibiotics and is conjunctivitis airborne?

Conjunctivitis means an inflammation of the conjunctiva. Usually pronounced: KON-junk-TY-vuh. The conjunctiva is the clear, vascular mucous membrane that covers the white of the eye and then folds back on the inside of the eyelids and extends to the edge of your upper and lower eyelids. The conjunctiva is an amazing structure that protects, lubricates, and acts as a barrier to the surface of the eye. It has an immune function, that we will discuss later, which helps the eye fight infection. It can heal, so that if it is damaged, it recovers very quickly. The conjunctiva also has some things that can go wrong, such as shrinking and tightening in conditions like scleroderma. It can become loose as we age, which can cause irritation and tearing. It can also scar in such conditions as pterygium, which are due to an aggressive healing response from damage from ultraviolet light from the sun. A pterygium is a salmon pink colored triangular thickened growth that extends out over the cornea, the clear window that protects the iris- the colored part of the eye. This is often seen in people who work outdoors in very sunny parts of the world.

For this blog post, we will be discussing inflammation of the conjunctiva known as conjunctivitis. Conjunctivitis can fall into numerous categories, but the big categories are: infectious conjunctivitis versus non-infectious conjunctivitis. Infectious conjunctivitis is subdivided into bacterial or viral infectious causes.  We will mostly limit this talk to viral conjunctivitis for which the medical term “pink eye” is used. Often people call every red eye “pink eye” regardless of the cause of the conjunctivitis. This is where the confusion lies.

The answer to the question: “Is pink eye airborne?” is a tricky one. If you define “pink eye” as viral conjunctivitis, the answer would be “no”. If you are referring to allergic conjunctivitis the answer is most often “yes“. Among Ophthalmologists, the medical term “pink eye” generally refers to viral conjunctivitis. Viral conjunctivitis is most often the result of viral transmission of a highly infectious but not usually dangerous virus which can be one of many viruses that can cause an infectious and contagious conjunctivitis. The discharge from “pink eye” has sometimes been cultured to be adenovirus or other viruses often with multiple serotypes. As an Ophthalmologist, I have never cultured a viral conjunctivitis because it is generally self-limited, resolves in 7 to 10 days, and most often has no lasting harm. Cultures are expensive, often have false negatives, and do not affect the treatment plan. The viruses that cause pink eye are not airborne and yet are highly contagious by person to person spread. They can be cultured from fomites-the medical term for any inanimate object that can harbor a contagious agent such as a virus. The viruses that cause infectious conjunctivitis have been cultured from towels, door knobs, etc., for up to 21 days.

Whenever you have a red eye that is bothering you, you may not know if it is serious or not. My advice is that anytime you have an eye problem that does not go away after a few days, you should seek out professional eye care. There are thousands of things that can cause red eyes, and while most are self-limited and not serious, there are some that can be very serious and cause loss of vision or permanent damage to your eyes. Pink eye, or more specifically viral conjunctivitis, does not require antibiotics. Antibiotics do not kill viruses and therefore are not effective. However, most of the time you go to an urgent care or emergency room for a red  or “pink” eye, you will leave with an antibiotic. This is why you must follow up with an eye care professional such as an Ophthalmologist or Optometrist. An Optometrist goes to Optometry school and is an Optometric Physician but is not trained to the extent of a MD. Ophthalmologists are Medical Doctors who complete Medical school and go on to complete a four-year residency in pathology and surgery of the eyes and visual system.

“Pink eye” is generally diagnosed through the history and physical examination of the eyes. There are certain markers and physical exam signs that lead an Ophthalmologist to the diagnosis of viral conjunctivitis. Generally, an Ophthalmologist will recommend supportive care for viral conjunctivitis. That is handwashing, not sharing towels, and disinfecting things that he or she may have touched while they were infectious. The course and duration of viral conjunctivitis is similar to that of the common cold. The infectious period is 1 to 7 days. The clinical period (symptoms) is 7 to 10 days. Viral shedding generally stops after a few days even though the eyes may still be red. Occasionally, an Ophthalmologist will prescribe a steroid to decrease the inflammatory component of viral conjunctivitis, but this may extend the shedding period somewhat. I have recommended to my patients either no medication or sometimes a steroid eye drop depending on the degree of the inflammation. There also can be some sub-epithelial corneal infiltrates from certain serotypes of adenovirus that respond well to a steroid eye drop. One must be careful with steroids because they can exacerbate other causes of ocular inflammation, such as a herpetic etiology. This is why treatment should be handled by an Ophthalmologist and never treated in an urgent care with steroids.

The above heading is self-contradictory. “Pink eye” by definition refers to infectious viral conjunctivitis. However the term “non-contagious pink eye” can mistakenly be used by the non-ophthalmologist. A non-contagious pink eye refers to any inflammation of the conjunctiva that is not due to an infectious ideology. There are many types of non-infectious or non-contagious conjunctivitis. This is outside the scope of this blog post. There are huge textbooks written on ocular pathology and many eye problems can cause an inflammation of the conjunctiva or “red eye“ that is not due to virus. There can also be inflammation of the sclera (the white collagen that makes our eyes look white) when the sclera is inflamed it is an omen of a much more serious ocular condition. There can be inflammation of the cornea (keratitis) which also can be a sign of a very serious and vision threatening pathology. This is why these diagnoses are best left to an Ophthalmologist who specializes in the pathology of the eyes and visual system.

Allergic conjunctivitis is a whole different topic, but is potentially confused with “pink eye.” Both conditions cause redness on the surface of the eye, however, allergic conjunctivitis is most frequently associated with itching. Infectious viral conjunctivitis also can have some itching but generally has more discharge and mucus. Allergic conjunctivitis can also have a ropy discharge from the eye, or strings that you can pull out of your eye. Gross right? This is why the diagnosis is best left in the hands of a qualified Ophthalmologist. Allergic conjunctivitis may be chronic and seasonal/predictable, whereas infectious viral conjunctivitis is not predictable or seasonal. Viral conjunctivitis can also be associated with cold symptoms such as a runny nose, cough, and general malaise. Systemic allergies can have these symptoms, too, which can be confusing. There are physical exam signs for the Ophthalmologist that may help differentiate these two conditions, but it is possible that they would be misdiagnosed.

In summary, “pink eye” itself does not need, nor is it responsive, to antibiotics because viral conjunctivitis is the result of a virus and not bacteria. Antibiotics are used for bacteria. Antivirals are for viruses. There are several ophthalmic antivirals, but they are not generally used for viral conjunctivitis or contagious “pink eye.” Allergy medication can help with allergies, but confusingly might also help somewhat with the symptoms of viral conjunctivitis. Take home message: if your eyes are red and don’t get better, see an eye doctor! I hope this has helped you understand that “pink eye” may be a non-infectious conjunctivitis but also can be an infectious or contagious conjunctivitis.