Spring is a time of high incidence of allergic conjunctivitis, and many patients with itchy eyes treat themselves with anti-allergy eye drops. However, itchy eyes are not necessarily caused by allergic conjunctivitis, as some patients experience these symptoms because of blepharitis, and the treatment differs between the two conditions. Inflammation of the lid margin is a chronic inflammation of the lid margin. It can be caused by bacteria, seborrheic dermatitis, or localized allergic reactions, and is often present in combination. It causes subacute or chronic inflammation of the lid margin surface, eyelashes, hair follicles, and their glandular tissues. Depending on the clinical features, blepharitis can be divided into three categories: scaly blepharitis, ulcerative blepharitis, and canthal blepharitis. Blepharitis is caused by a combination of mild infection due to a high secretion of sebum from the lid sebaceous glands and the lid glands, with squamous blepharitis being mostly yeast-like mycobacteria or S. furfur; ulcerative blepharitis being predominantly staphylococcal; and canthal blepharitis being caused by Mo-a-rax (Mo-rax-Axenfeld) bifid infection, and others such as stimulation by wind, sand, smoke, dust, heat, and chemical factors, refractive error, eye fatigue, and Other factors such as irritation from sand, smoke, heat, and chemicals, refractive error, eye fatigue, lack of sleep, decreased systemic resistance, and nutritional deficiencies such as vitamin B2 are common causes of all three types of blepharitis. Patients with scaly blepharitis often have itchy eyes, flushed lid margins, and scalp-like scales at the roots of the eyelashes and on the surface of the lid margins. In a few cases, the sebum is concentrated at the base of the eyelashes in a waxy yellow crust, which, when removed, is only locally congested and does not have an ulcerated surface. The disease is slow to develop and can sometimes cause hypertrophy of the lid margin. Ulcerative blepharitis is the most severe of the three types, with yellow scabs and small pustules at the roots of the eyelashes, which are glued into bundles and peeled away to reveal bleeding ulcers and small pustules at the roots of the eyelashes. As the hair follicle is destroyed, the eyelashes fall out and cannot be regenerated, resulting in bald eyelashes. When the ulcer heals, a scar is formed, and when the scar contracts, it pulls on the neighboring lashes that have not been shed, causing them to grow indiscriminately and irritating the eye. If the disease is prolonged, the lid margin becomes hypertrophic and ectropic, and the tear dots become occluded, resulting in tearing. Blepharitis of the canthus is mostly bilateral and is common in the outer canthus. It is characterized by redness, erosion, and moistening of the skin of the medial and lateral canthus with mucous secretions. In severe cases, chalazion occurs and is often combined with canthal conjunctivitis. Treatment of blepharitis begins with removing the cause, avoiding all irritants, correcting refractive errors, paying attention to nutrition, exercising, and treating other chronic systemic diseases to improve the quality of the body; locally, a cotton swab dipped in warm saline is used to remove the scab and allow the excess secretion of the sebaceous glands and lid glands to drain. Then apply antibiotic ointment to the lid margin 2 to 3 times a day, and make sure the treatment is thorough and not interrupted. If there is also conjunctivitis, antibiotic eye drops should be applied. In patients with recurrent and prolonged disease, bacterial cultures and drug tests should be performed to select effective drugs. In the case of canthal blepharitis, diligent ocular spotting of 0.25% to 0.5% zinc sulfate solution or antibiotic eye ointment coating along with internal administration of riboflavin has special therapeutic efficacy.