Itchy and swollen lower eyelids may be caused by allergies, blepharitis, conjunctivitis and other diseases. 1. allergy: lower eyelid itchy scratch two swollen will first consider is caused by allergies, allergic substances stimulation will lead to eyelid itching, hard scratching will lead to tissue fluid oozing, edema phenomenon. 2. blepharitis: the eyelid margin skin, eyelash follicles and glands are caused by bacterial infection, which will lead to the exudation of tissue fluid under stimulation, resulting in edema of the lower eyelid. 3. Conjunctivitis: Conjunctivitis is caused by infection, under the stimulation effect, the conjunctiva will be congested, it will lead to dilation of blood vessels in the eyes and increase in secretion, because the lid conjunctiva itself is part of the eyelid, so it will also lead to eyelid swelling. If the lower eyelid itchy scratching two swollen symptoms are not relieved, or accompanied by other symptoms of discomfort, you should go to the hospital in time, clear cause to give targeted treatment.