It is one thing to occasionally have red eyes. It's another to have conjunctivitis, a condition caused by the infection or inflammation of the transparent membrane that covers the eyeball or inner eyelid. Often referred to as pink eye, conjunctivitis is characterized by redness, itching, burning, tearing, and a discharge that can cause crusting around the eye. Since it can be contagious and have complications, it's important to recognize its signs and symptoms, be evaluated, and, if needed, get treatment.
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Frequent Symptoms
When some people hear the term "pink eye," they often take it to mean the highly contagious viral form known as epidemic keratoconjunctivitis (EKC). EKC is associated with the cold virus and can sweep through a school, daycare, or office as those who are infected cough, sneeze and pass the virus to peers.
However, other bacteria and viruses can also cause conjunctivitis, as can allergies or chemical contaminants.
Symptoms of EKC are in line with those common to all forms of conjunctivitis, including:
- A pink discoloration of one or both eyes
- A gritty feeling in the affected eye
- Itchy or burning eyes (ocular pruritus)
- Excessive tearing (epiphora)
- Swollen eyelids
- Blurred vision
- Increased sensitivity to light (photophobia)
- A discharge from the eye that can form a crust at night
While EKC is usually limited to the above, other forms may involve these and additional symptoms.
By Cause
Pink eye can be contagious or non-contagious. If you suspect you have it, a healthcare provider can evaluate your symptoms to determine both the cause and the appropriate course of treatment.
Conjunctivitis can be broadly classified into three groups: infectious conjunctivitis, allergic conjunctivitis, and chemical conjunctivitis.
While they all tend to manifest with symptoms of redness, discomfort, and tearing, there may be subtle variations that differentiate one from the next.
Viral Conjunctivitis
Viral conjunctivitis is associated with upper respiratory infections and colds. It usually affects only one eye but may affect both if you rub your eyes.
Viral conjunctivitis can often cause a watery discharge that may be clear, sticky, or slightly milky. Because it is closely aligned with respiratory infections, the pink eye may be accompanied by coughing, sneezing, nasal drip, and a sore throat. Swollen lymph nodes are also common.
Typically, if you have viral conjunctivitis, the third through fifth days of the infection will be the worst. After that, the eyes will begin to improve on their own.
In addition to EKC, other viral causes include the herpes simplex virus (HSV), which can affect children and cause recurrent infections in adults. While less common than EKC, it can be more problematic if it moves toward the center of the cornea (clear covering of the colored portion of the eye).
Bacterial Conjunctivitis
Unlike the viral form of pink eye, bacterial conjunctivitis will typically affect both eyes and produce a thick, yellow-green discharge. Among the bacterial types involved, Staphylococcus, Streptococcus, Corynebacterium, Haemophilus, Pseudomonas, and Moraxella species are the most common.
Because the purulent (pus) discharge can be profuse, the crust around the eyes will usually be thicker and may even "glue" the eyelids shut in the morning. Swollen lymph nodes are less common but can occur with severe gonorrheal infections.
Gonorrhea or chlamydia may also cause a form of conjunctivitis known as ophthalmia neonatorum in which the bacterium is transferred to a newborn's eyes as it passes through the mother's birth canal. While most of these infections are avoided due to the standard use of antibiotics after delivery, untreated infections can lead to eye pain, swelling, and a purulent discharge within the first month of life.
Allergic Conjunctivitis
Allergic conjunctivitis may be triggered by multiple causes, including seasonal allergies or food allergies.
Allergic conjunctivitis will typically affect both eyes and may be accompanied by classic allergy symptoms such as hives, itchiness, or allergic rhinitis (sneezing, congestion, swollen eyes).
While excessive tearing is common, eye discharge is less so. In severe cases, a rash can break out on the conjunctiva itself.
Another form of allergic conjunctivitis, known as giant papillary conjunctivitis (GPC), is caused when a persistent foreign object on the eye (such as contact lenses or eye sutures) triggers the development of pimple-like papules on the inner eyelid.
Chemical Conjunctivitis
Chemical conjunctivitis, also known as toxic conjunctivitis, is characterized by acute redness, tearing, and pain in response to smoke, fumes, or liquids. Mild cases, such as those involving chlorine or smoke, tend to improve within a day.
Exposure to harsher chemicals may take longer to resolve. Injuries like these can trigger the hyperproduction of eye mucus (an immune response meant to protect the eye) or cause the proteins of conjunctiva break down to form a protective barrier over the cornea. Vision loss may be temporary or permanent depending on the extent of the corneal injury.
Complications
Most cases of conjunctivitis are relatively mild and will not cause eye damage of any sort. In rare cases, complications may develop that can be serious and even life-threatening.
Among some of more commonly seen complications of conjunctivitis:
- Punctate epithelial keratitis: This is characterized by an infection of the cornea (keratitis) accompanied by the formation of tiny holes in the conjunctiva. The recurrence of a herpes infection is a common cause. In addition to eye pain, extreme light sensitivity can occur as the tiny perforations cause light to diffuse abnormally. While distressing, the symptoms tend to resolve within several weeks with the use of topical antivirals.
- Ophthalmia neonatorum: This is commonly avoided today due to the routine screening of sexually transmitted infections in mothers and the use of neonatal antibiotics in newborns. Babies left untreated are at risk of vision loss and blindness. Moreover, around 20 percent of babies with chlamydial conjunctivitis will develop pneumonia, a potentially life-threatening complication in newborns.
When to See a Healthcare Provider
As certain types of pink eye are contagious, you should see a healthcare provider if your symptoms are accompanied swollen lymph glands or any signs of a respiratory infection. This is especially true for school-age children who are common targets of community-transmitted viruses.
Even if there are no other overt symptoms, you should still see a healthcare provider or ophthalmologist if your pink eye persists for longer than two weeks.
On the other hand, you should call your healthcare provider immediately if you experience any of the following symptoms:
- High fever (over 100.4 degrees)
- A thick yellow or green discharge from the eye
- Severe pain when looking at a bright light
- Blurred vision, double vision, vision loss, or you see bright halos around objects
These are signs of a severe infection that may require more aggressive treatment.