What can cause Swelling under one eye and redness in that eye?

There are many potential causes for swelling under one eye and redness in that eye. Some of the most common causes include:

* Allergies: Allergies can cause the eyes to become red, itchy, watery, and swollen. Swelling under one eye and redness in that eye can be caused by an allergic reaction to substances such as pollen, dust, pet dander, or certain foods.

* Styes: A stye is a small, red, and swollen bump that forms on the edge of the eyelid. Styes are caused by a bacterial infection and can be very painful.

* Blepharitis: Blepharitis is a condition that causes inflammation of the eyelids. Blepharitis can be caused by a variety of factors, including bacterial infections, allergies, and skin conditions such as rosacea.

* Conjunctivitis (pink eye): Conjunctivitis is an inflammation of the conjunctiva, the clear membrane that lines the eyelid and covers the white part of the eye. Conjunctivitis can be caused by a variety of factors, including bacterial infections, viral infections, and allergies.

* Corneal ulcer: A corneal ulcer is an open sore on the cornea, the clear front part of the eye. Corneal ulcers can be caused by a variety of factors, including infections, injuries, and certain medical conditions.

* Orbital cellulitis: Orbital cellulitis is an infection of the tissues surrounding the eye. Orbital cellulitis can be a serious condition and can lead to vision loss if not treated promptly.

If you are experiencing swelling under one eye and redness in that eye, it is important to see a doctor to determine the cause and receive appropriate treatment.