There are many reasons for the redness of the eyelids of patients, which are commonly caused by mosquito bites, eye allergies, eye infections and so on. 1. Mosquito bites: when the patient suffers from mosquito bites, the affected area of the skin can appear swelling, redness, patients can also be accompanied by itching and other symptoms. 2. Eye allergy: some patients with allergies, in contact with allergens such as pollen, dust, animal fur, etc., the body has an allergic reaction, the patient may appear red, swollen eyes, itching and other symptoms. 3. Eye infections: Patients with eye infections such as blepharitis and blepharitis may experience redness, swelling and pain in the eyes. It is recommended that patients with significant eyelid congestion consult a doctor to evaluate their condition and follow the doctor’s instructions for treatment.