From Mayo Clinic News Network, Mayo Clinic News Network (TNS)

When a child has a red eye, it can be hard to tell the difference between a scratch on the eye (abrasion) and an infection like pink eye. Both can cause a pinkish-red color to the white part of the eye and excessive tearing. If the child is not old enough to tell you what is going on, they may just cry and rub their eyes.

Mayo Clinic Health System ophthalmologist Naomie Warner explains key differences between the two:

An abrasion is typically one eye only. Abrasions can happen even if you don’t realize you were scratched with something. Often, if you get something in your eye or have a scratch on the eye, you may not feel it for the first few hours, and the pain starts later.

Abrasions are painful and cause extreme light sensitivity. It’s not uncommon for a person with an abrasion to want to cover their eye or not open it unless the room is dark. Pain from an abrasion is some of the most severe discomfort you can experience. The pain remains when your eyes are closed. The excessive tearing you have with an abrasion is quite bothersome and will constantly run down your cheek if you don’t wipe the tears away. An eye abrasion may also cause a runny nose.

An infection, on the other hand, can start in one eye and spread to the other within a few days. Usually, the second eye is not as irritated as the first. Infections are itchy, and you will find children trying to rub their eyes. This, in turn, can cause the virus to spread to others as tears get on hands and are subsequently transferred to doorknobs or counter tops — where they can live for weeks. Infections may cause light sensitivity as well, but not as severe as an abrasion. Kids typically won’t keep their eyes closed when exposed to bright lights.

When should you bring your child in to see a health care provider? An abrasion will typically heal itself in one day. If the affliction persists longer than 24 hours, seeing a health care professional is important in order to prevent the abrasion from turning into an ulcer. An ulcer is a severe infection in the eye that can lead to permanent vision loss if not treated promptly.

Classic pink eye is caused by a virus and will run its course in two weeks with or without treatment, but it’s essential to see a health care professional to ensure it’s not a bacterial infection that needs antibiotics. This especially is true if the eye has any discharge or mucus that you need to wipe away with a tissue.

“As with any health condition, no matter if it is an abrasion or pink eye, proper hand-washing techniques are absolutely necessary to prevent further infection or spread of disease,” says Warner.

©2016 Mayo Foundation for Medical Education and Research. Distributed by Tribune Content Agency, LLC.

Photo: When a child has a red eye, it can be hard to tell the difference between a scratch on the eye (abrasion) and an infection like pink eye. (Photo courtesy Fotolia/TNS)