Swelling of the lower eyelids in the morning may be caused by excessive drinking before going to bed, allergic conjunctivitis or blepharitis. 1. Physiological factors: If a child drinks too much water before going to bed or stays up late for a long time, it can lead to swelling of the lower eyelids in the morning. 2. Allergic conjunctivitis: If allergic children are allergic to bedding such as quilt covers and pillowcases, allergic conjunctivitis can occur, so after waking up, the patient’s eyelids may appear swollen, and may be accompanied by eye itching and other uncomfortable symptoms. 3. Blepharitis: Blepharitis refers to suppurative inflammation of the eyelids. If a child’s eyelids become infected, the inflammation stimulates eyelid swelling, which can be accompanied by pain, burning and other uncomfortable symptoms. It is recommended that children with significant eyelid swelling be seen by a physician for evaluation and treatment.