Which condition is characterized by periorbital swelling, erythema, and tenderness to palpation?

The condition characterized by periorbital swelling, erythema, and tenderness to palpation is indeed periorbital or preseptal cellulitis. This condition occurs when there is an infection involving the soft tissues of the eyelids and surrounding areas, typically following a sinusal infection or trauma. The inflammation in periorbital cellulitis leads to noticeable swelling and redness around the eye, and because it is an infectious process, it often results in tenderness when the affected area is palpated.

In contrast, conjunctivitis typically presents with eye redness and discharge but does not generally involve significant swelling or tenderness in the surrounding tissues. An allergic reaction, while it can lead to some degree of swelling and redness, usually does not cause the same level of tenderness or localized inflammation associated with infection. A chalazion, although it can cause localized swelling on the eyelid, is a result of a blocked sebaceous gland and does not typically present with significant erythema or tenderness to palpation as seen in cellulitis.