Many people have experienced tender and swollen eyelids – perhaps as the result of an allergy – but in some cases, irritated eyelids may actually point to a more serious condition called a chalazion.
According to the American Optometric Association, a chalazion is a “slowly developing lump that forms due to blockage and swelling of an oil gland in the eyelid.” After the initial symptoms of red, tender and swollen eyelids, a chalazion can grow to the size of a pea and is typically found on the upper eyelid.
Unlike a sty, a chalazion is not an infection; instead, the AOA suggests that it results from a blockage of the oil gland. When the oil builds up inside the gland, it forms a lump. In some cases, the lump may break open and cause the eyelid to become inflamed. (American Health Advantage)