What is blepharitis?

Blepharitis is characterized as an inflammation of the eyelids, which typically involves irritation, redness, and swelling of the eyelid margins. This condition can occur due to various factors, including seborrheic dermatitis, blocked oil glands, or bacterial infections. Individuals with blepharitis may experience symptoms such as burning, itching, and crusty eyelids, particularly upon waking.

The other options describe different eye conditions or reactions. For instance, an infection of the cornea pertains to keratitis, which is a separate and more serious condition involving the clear front surface of the eye. An allergic reaction can result in symptoms like redness and swelling, but it does not specifically refer to the eyelids alone. Dry eye syndrome, while it can occur alongside blepharitis, involves a different issue where the eyes do not produce enough tears or the tears evaporate too quickly. Thus, blepharitis specifically refers to the inflammation of the eyelids, making the choice referring to this condition correct.