Can lead to eyelid redness, swelling and itching of more factors, such as mosquito bites, trauma, allergies and so on. 1. mosquito bites: this phenomenon is more common in the summer, sleep accidentally bitten by mosquitoes eyelids will appear red and itchy, but the general symptoms will not be particularly obvious, and itching phenomenon will soon disappear. 2. Trauma: when the eyelids are traumatized by external forces, the eyelid area will also appear red, swollen and itchy. 3. Allergy: allergens such as pollen, dust, animal dander, or the use of unhealthy cosmetics, eating seafood, etc., may cause allergic inflammation, the eyes may also appear red, swollen, itchy and other uncomfortable symptoms. If the redness and swelling of the eyelids can not be relieved, you should go to the hospital in a timely manner, after clarifying the cause of the disease, follow the doctor’s instructions for treatment, do not take care of yourself, so as not to cause adverse consequences.