Is it pink eye (conjunctivitis) or something else?
If your eyes appear redder than usual and you are experiencing discomfort, you may assume you have developed pink eye (also known as conjunctivitis). This common condition can cause eye redness, but many other eye conditions have similar symptoms.
Minor eye redness often clears up by itself. However, to avoid misdiagnosing yourself, it is important to consult an eye doctor for an accurate diagnosis, especially if you experience:
- Persistent redness
- Intense pain
- Excessive discharge
- Vision changes
Causes of pink eye
The term conjunctivitis broadly refers to inflammation of the conjunctiva. This is the transparent membrane lining the inner eyelid and the eye's white area (sclera).
This inflammation can be caused by various factors, including:
- Allergies
- Infections
- Irritants
- Underlying health conditions
Allergies to pollen, weeds and grass are very common, as are allergies to smoke, perfumes and dust mites.
The most common cause of viral conjunctivitis is adenovirus infection. Adenovirus is the group of viruses that cause cold or flu-like symptoms. Other viruses, such as the herpes simplex and varicella-zoster viruses, can also cause red eyes, pain and vision changes.
COVID-19 can also produce conjunctivitis symptoms such as red, swollen eyes. In fact, these symptoms can be the initial symptoms of a COVID-19 infection.
READ MORE: What causes pink eye (conjunctivitis)?
Symptoms of pink eye
Symptoms differ depending on the causes. While allergies cause redness in both eyes, bacterial and viral conjunctivitis can affect one or both eyes.
Common allergic symptoms include:
- Clear watery discharge
- Itching
- Mild redness
Bacterial infections typically cause mild discomfort, but their appearance can be dramatic, with:
- Redness
- Swelling
- Crusting
- Yellow-green discharge
Contact lens wearers are at higher risk of developing a bacterial corneal ulcer, a condition causing severe pain and light sensitivity.
Viral infections often cause:
- Mild soreness
- Redness
- A gritty or sandy feeling, as if something is in the eye
- Moderate to severe light sensitivity is also possible
LEARN MORE: Signs and symptoms of pink eye
Common conditions that cause eye redness
Red eyes are usually caused by blood vessels that are swollen or dilated, and there are many conditions that cause this, including:
Dry eye
The symptoms of dry eyes include eye redness, gritty or watery eyes, and discomfort. This can be caused by wearing contact lenses, taking certain medications, environmental factors like dry air and smoking, autoimmune conditions, or another underlying eye issue.
Being over 50 years old is the most common cause of dry eye, as tear production decreases as you age. Contact lenses can disrupt the stability of the tear film that keeps your eyes lubricated. Hormonal changes (caused by pregnancy or the use of oral contraceptives) can also impact tear production. Dry eye can also be a side effect of some common medications, such as antihistamines, beta-blockers and antidepressants.
Prolonged computer use can lead to dry eyes and redness because many people do not blink as frequently, which can lead to irritation.
Blepharitis
Blepharitis is eyelid inflammation that results in swelling. It can be caused by bacterial overgrowth, infestation of Demodex mites or malfunctioning oil glands in the eyelids. When someone has blepharitis, the normal function of the oil-producing glands that help keep the tear film stable is often disrupted, leading to dry eyes, irritation and redness.
Keratitis
Keratitis is inflammation of the cornea (the clear front layer of the eye) due to infectious or noninfectious causes. It can lead to redness, pain, discharge, inflammation and vision changes. A mild or early case of keratitis could be initially mistaken for pink eye by someone who is not a trained professional.
To reduce the risk of corneal infections:
- Wash your hands often.
- Don't touch your eyes.
- Always remove eye makeup and contact lenses before bed.
Antibiotic treatment may be necessary if keratitis is caused by a bacterial infection.
Iritis
Anterior uveitis, or iritis, occurs when the front part of the uvea (the middle layer inside the eye) becomes inflamed. The uvea includes the iris (the colored part of the eye). While this condition is not common, redness is one of the most noticeable symptoms. Early treatment is critical as iritis can cause serious vision issues.
Stye
A stye is a small, painful bump that looks like a pimple and develops at the edge of the eyelid by an eyelash. It typically causes redness, swelling and discomfort. Although styes usually go away on their own, they sometimes require treatment.
Subconjunctival hemorrhage
At times, small red blood spots might develop on the normally white part of the eyes. It's understandable to be concerned, but they usually resolve on their own in most cases. The many tiny blood vessels in the eyes are delicate and can rupture easily, even after heavy lifting or sneezing.
Episcleritis and scleritis
Episcleritis and scleritis are inflammatory conditions of the eye that can be mistaken for pink eye due to redness in the eye. However, they are very distinct conditions, and the redness results from inflammation of different layers of the front of the eye.
Episcleritis is generally not serious and typically goes away on its own. Scleritis is much more severe and caused by inflammation in a deeper layer, leading to significant pain and severe vision issues. While conjunctivitis may cause discharge, scleritis and episcleritis typically do not.
Pinguecula and pterygium
Excessive exposure to the sun's ultraviolet rays can lead to the development of two types of growths on the conjunctiva: pingueculae and pterygium. Although these growths have different characteristics, they both cause eye irritation and redness.
A pinguecula is a yellowish growth that usually forms on the conjunctiva, either at the inner or outer corner. This growth is composed of calcium, fats or proteins. In severe cases of pinguecula, the tear film may be affected, potentially leading to dry eye disease. Treatment usually begins with artificial tears, although prescription drops may be necessary in more severe cases.
A pterygium is another type of conjunctival growth that often occurs in individuals who spend long periods in the sun and water. It’s commonly referred to as “surfer’s eye.” One of the complications associated with a pterygium is its potential to distort the cornea, which can impair vision. Artificial tears or drops to reduce inflammation may be prescribed for mild cases. If vision is affected, surgery may be necessary.
What is commonly misdiagnosed as pink eye in toddlers?
If your toddler has red, irritated eyes, it is best to watch them closely, and if the symptoms persist, contact their doctor. Eye redness in toddlers can be caused by many conditions in addition to conjunctivitis, including:
Injury
Toddlers often bump into furniture and other objects as they learn to walk and navigate their surroundings. They may also rub their eyes vigorously when they are tired. This can lead to broken blood vessels that cause the eye to appear red.
If your toddler appears to be in pain, has excessive discharge or complains of blurry vision, they may have a corneal abrasion (scratch) or they may have gotten a harmful chemical into their eye.
Contact an eye doctor as soon as possible to ensure that your toddler’s injury is treated quickly. If you suspect a chemical injury, immediately flush their eyes for at least 20 minutes and seek medical attention.
Vitamin A deficiency
Vitamin A deficiency is rare in the United States, and it is unlikely that anyone with red eyes is experiencing redness due to a lack of the vitamin. However, certain health conditions, such as inflammatory bowel disease (IBD) and liver disease, can increase the risk of vitamin A deficiency. Symptoms can vary in severity, but eye redness is one common sign.
LEARN ABOUT the eye benefits of vitamin A
Blocked tear duct
The small tubes that drain tears from the eyes to the nose can be blocked in some infants, resulting in redness, tearing and irritated eyes. If you notice these symptoms, speak to your child’s pediatrician. A blocked tear duct often resolves on its own or with regular gentle massage of the tear duct area by the nose.
READ NEXT: Eye discharge in newborns, babies and toddlers: Causes and treatment
When to call a doctor
Temporary eye redness is common and can result from conjunctivitis (pink eye), dry eye, and various other causes. In many instances, the redness resolves on its own without treatment. However, professional medical care is sometimes required.
See a doctor if eye redness persists or is accompanied by pain, vision problems, light sensitivity, or any eye discharge. If you or your child has eye redness that is accompanied by severe pain, fever, or swelling, seek immediate medical attention.
Anastasia Climan, RDN, CD-N, also contributed to this article.
