If the patient’s eyelids suddenly become itchy and swollen, it may be related to mosquito bites or due to allergic blepharodermatitis or blepharitis. 1. Mosquito bites: If the skin in the eyelid area of the patient is suddenly bitten by mosquitoes, resulting in toxins attacking the local skin, it may cause the patient’s eyelids to become suddenly itchy, swollen and other discomforts. 2. Allergic blepharitis: when allergic patients are exposed to pollen, cosmetics and other allergens, an allergic reaction occurs and the patient may suddenly experience itchy, swollen eyelids and other discomforts, which may be accompanied by localized rashes, burning sensation and other discomforts. 3. Blepharitis: Blepharitis, also known as granuloma, is a suppurative inflammation of the eyelid glands, and patients may experience redness, swelling, itching, pain and other discomforts of the eyelids, and patients can follow the doctor’s instructions to use tobramycin dexamethasone and other medications, to promote the recovery of the condition. It is recommended that patients with sudden itching and swelling of the eyelids should consult a doctor in time to assess their condition and follow the doctor’s instructions for treatment.