A child with one swollen eye may be associated with blepharitis, eye trauma, mosquito bites and other causes. 1. Blepharitis: Blepharitis refers to purulent inflammation of the eyelid glands. Under the stimulation of inflammation, the child may experience redness, swelling and pain in the eyelids. 2. Eye trauma: If a child’s unilateral eye is accidentally squeezed or bumped, it can cause damage to the soft tissues of the affected area, resulting in eye swelling and pain. 3. Mosquito bites: mosquitoes bite the eyelids, can be released into the body of certain substances, can cause the body to occur abnormal immunity, causing localized redness, swelling, itching and other symptoms. It is recommended that patients with obvious eye swelling and other discomforts should consult the hospital in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.