Ophthalmologist Questions Pink eye

How do allergies cause pink eye?

My son was diagnosed with pink eye, but his doctor said that this his case is due to allergies and not a bacterial infection. How do allergies cause pink eye?

7 Answers

They cause the veins and arteries in your eye to dilate making your eye appear 'pink".
Allergies cause the release of a substance called histamine which enlarges the blood vessels making the eye pink
Allergies can cause irritation and the release of histamines. These molecules can cause vasodilation and tearing...leading to a pink eye and signs and symptoms very similar to conjunctivitis from an infection. There is generally clear tears without mucoid discharge from an allergy as opposed to a bacterial infection.
Pink eye is not a diagnosis but a description. When the eyes are irritated by an allergy, histamine release causes the vessels around the eye to dilate and thus the pinkness. We see this in allergy to very serious diseases that affect the eye. It is treated with topical allergy drops.
I think the biggest part of that question is understanding that most people use the words pinkeye to describe a very specific condition that is often in kids and is caused actually by a virus, or more specifically the addenovirus. Many other conditions can cause the eyes to look pink, which is just a sign of inflammation. Other diagnoses can be allergic, systemic inflammatory conditions, bacterial infections, trauma or other viral infections . The viral infection that causes “ pinkeye “ in kids and can easily spread to the other eye or two other people they are around typically causes irritation increased tearing, and itchiness. If it is mild, common treatments include cool artificial tears, cool compresses, and good hygiene to try and prevent spread to the other Eye or to other people. Allergens can cause a similar pinkness of the white part of the eye due to causing increased inflammation and making the blood vessels dilate more. I believe it is important to have your son checked by an eye doctor because his various causes of pinkness in the eye may require different types of treatment Both in the short term and long term.
The term "Pink Eye" is a nonspecific layperson's term for anything that causes a red eye. It most commonly refers to a viral conjunctivitis, that is a viral infection of the conjunctiva, the pink tissue lining the inside of the lids and covering the surface of the eyeball. The term can also refer to ANYTHING that makes the eye "pink" or "red" which is a manifestation of dilated veins on the white part of the eye. This could be viral, bacterial or allergic
Allergies cause inflammation and discharge of chemicals that irritate the eyes.