Swollen eyelids can have various causes, including allergies, bacterial infections like barley, or inflammatory conditions such as chalazion or blepharitis. Symptoms of swollen eyelids include redness, pain, itching, and swelling of the upper and/or lower eyelids of one or both eyes. Common causes are transient issues like allergies or infections like barley, which usually heal on their own or with treatment. More long-term issues can be due to blockages in the eyelid glands from conditions like chalazion or blepharitis, which may require care and potentially surgery or antibiotic therapy to treat.