The surface of the eye is often exposed to the external environment and is easily exposed to various allergenic substances, resulting in various ocular allergic diseases, of which allergic conjunctivitis is the most common. Allergic conjunctivitis is most common. In summer, allergic conjunctivitis is easily triggered by the high frequency of air conditioning, the large difference between indoor and outdoor temperatures, and the tendency of air conditioners to harbor dust mites. Itchy eyes may develop. Common allergic conjunctivitis includes seasonal allergic conjunctivitis, perennial allergic conjunctivitis, contact allergic conjunctivitis, giant papillary conjunctivitis, and springtime keratoconjunctivitis. Seasonal allergic conjunctivitis is the most common type of allergic conjunctivitis, the allergen is mainly plant pollen, often spring onset, rapid onset, contact with allergens can occur, the symptoms are quickly relieved after leaving the allergen, patients mostly have a history of allergic rhinitis, asthma, etc. Perennial allergic conjunctivitis is less common, and the patient’s symptoms persist because the antigens (dust, dust mites, animal fur and feathers, etc.) are present all year round. Contact allergic conjunctivitis has a clear history of allergen exposure, such as a history of direct contact with medications or cosmetics. Macrophthalmic conjunctivitis often has a history of contact lens wear. Springtime keratoconjunctivitis is most often seen in children, with onset in spring and summer and remission in fall and winter. It is difficult to find a specific allergen, and the onset is related to humoral and cellular immunity, with itchiness being the main symptom. Atopic keratoconjunctivitis is more common in the elderly. Wearing contact lenses can also cause the disease. There are various allergens that cause allergic conjunctivitis, the most common being pollen, dust, dust mites, animal hair and other small substances, followed by perfumes, cosmetics, and substances that can come into direct contact with the eye, such as medications, contact lenses and their care solutions. When allergens come in contact with the eye surface, they stimulate mast cells to release histamine, leukotrienes, prostaglandins and other inflammatory mediators, and the eye can become red, swollen and itchy. Allergic conjunctivitis occurs in spring and summer, especially during seasonal changes and temperature variations. In spring and summer, pollen floats in the air as flowers bloom; in summer, air conditioners are used frequently and the temperature difference between inside and outside the home is large, and air conditioners tend to harbor dust mites, which can easily induce allergies. The incidence of allergic conjunctivitis is increasing year by year with the increase in air pollution, eye cosmetics and contact lenses. Other symptoms include foreign body sensation, photophobia, tearing, burning sensation and increased mucus-like secretions. Springtime keratoconjunctivitis and atopic keratoconjunctivitis may also result in vision loss due to corneal involvement; long-term, severe allergic conjunctivitis may cause damage to the mucous membrane of the ocular surface, resulting in dry eye symptoms such as ocular dryness and foreign body sensation. The most common signs of allergic conjunctivitis are conjunctival congestion, lid conjunctival follicle formation, and in some severe cases, pavement-like giant papillae of the upper lid conjunctiva and corneal shield ulcers. Antibiotic therapy is ineffective The main treatment for allergic conjunctivitis is pharmacological, with four major classes of drugs including antihistamines, mast cell stabilizers, nonsteroidal anti-inflammatory drugs, and glucocorticoids, with additional immunosuppressive agents for more severe cases. Among them, glucocorticoids are more effective, but they have more complications and are suitable for patients with severe disease, and should be used under the guidance of a doctor. In addition, eye ice can reduce the discomfort; using artificial tears to spot or rinse the eyes can reduce the concentration of allergens and inflammation-causing factors. Antibiotic treatment for allergic conjunctivitis is generally ineffective and abuse should be avoided. Please refer to the doctor’s instructions for the specific medication to be used.