Swelling of the eye, also referred to as periorbital puffiness, refers to the presence of excess fluid (edema) in the connective tissues around the eye, most commonly the eyelids. A swollen eye can result from trauma, infections, or other injuries to the eye area. Prolonged crying is a common cause of swollen eyes. Virtually any cause of inflammation to the eye area may manifest as eyelid swelling, although allergic reactions are likely the most common cause. With allergic reactions, the eyes may also be red and itchy as well as swollen. Rarely, systemic conditions (affecting the entire body) may result in fluid retention, including fluid retention in the tissues around the eyes.