Eyelids are always allergic to redness, swelling and itching may be skin allergies, blepharitis and other reasons. 1. Skin allergy: Patients who are exposed to allergens, such as pollen, dust mites, willow floss, or certain cosmetics, hair dyes, etc., can cause allergic phenomena, such as redness, swelling, itching, etc., of the skin of the patient’s eyes. 2. Blepharitis: also known as granuloma, is a localized inflammation caused by bacterial infection, the patient manifested as redness and swelling of the eyelid skin, touching the infected area can feel the skin temperature rise, the patient has a sense of tenderness, and allergy symptoms are similar. Patients need to pay attention to personal hygiene, do a good job of eye cleaning, avoid rubbing the eyes with dirty hands. Eyelids are always allergic to redness, swelling and itching may also be caused by other reasons, if the above symptoms do not improve significantly or further aggravation, you should go to the hospital in a timely manner, under the diagnosis and guidance of professional doctors for treatment.