Waking up with a swollen eyelid can be caused by physiological factors, insect bites, conjunctivitis and other diseases, as well as other diseases such as blepharitis. 1. Physiological factors: when a patient wakes up with a swollen eyelid, it may be caused by an incorrect sleeping position that squeezes one of the eyes, or it may be caused by drinking too much water before going to bed. 2. Insect bite reaction: insect bite reaction is mostly related to insect bites, such as lice, fleas, mosquitoes, midges and so on. Patients will have redness, swelling, erythema or blisters on the bites, and itching. 3. Conjunctivitis: Conjunctivitis has a variety of causes, mainly including bacterial and other pathogenic infections, immune diseases, etc. The main symptoms are redness of the eyes, foreign body sensation, dryness, itching, etc., but also tearing, increased secretion and other symptoms. If the patient has conjunctivitis, it will cause the patient to wake up one eyelid swollen phenomenon. 4. Other diseases: Blepharitis, blepharitis and other diseases can also cause patients to wake up with a swollen eyelid. If the patient wakes up with a swollen eyelid, if it is caused by physiological factors, no special treatment is needed. If it is caused by a disease, the patient should consult a doctor in time and follow the doctor’s instructions for treatment.