Allergic conjunctivitis in children is an IgE-mediated inflammatory disease of the eye stimulated by allergens, mainly caused by type I and type IV hypersensitivity reactions, and is a non-infectious ocular surface disease in children. The clinical manifestations of allergic conjunctivitis are: a. Etiology: 1. The child has atopic constitution, meaning that the child has an abnormal constitution and is particularly sensitive to certain stimuli, as shown by the tendency to have allergic or exudative lesions on the skin and mucous membranes; 2. Most scholars believe that allergic conjunctivitis in children may be a polygenic genetic disease, and studies have pointed out that increased IgE levels in patients may be controlled by a dominant gene on the 11th chromosome pair. It has been suggested that increased IgE levels may be controlled by a dominant gene on chromosome 11 and an immune response gene near the HLA region on chromosome 6. In a clinical survey of patients with AC, it was found that about 40% of family members have atopic traits; 3. Allergens: usually can be divided into inhalation allergens, ingestion allergens, contact allergens, and inoculation allergens. Clinical detection is mainly concentrated in indoor dust (67%), spring pollen (63. 4%), dust mites (58%) and fungi (70%), food mainly shrimp and crab. 4. Seasonal and weather factors: Most patients have allergy symptoms during the allergy season. 5, other factors: such as mental stress, infection, cold stimulation can trigger the occurrence of allergic conjunctivitis in children or make the symptoms worse. Symptoms: Itchy eyes, lacrimation, photophobia, foreign body sensation, recurrent eye redness, morning mucous-like discharge, sneezing, runny nose, etc. The main symptoms are itchy eyes (99%-100% incidence) and foreign body sensation, and rubbing eyes and lacrimation in infants and children. There are also children with allergic conjunctivitis with cough and general discomfort as the main symptoms. Parents should pay special attention to their children when they have these symptoms and visit an ophthalmologist to find out if allergic conjunctivitis has occurred. Allergic conjunctivitis in children presents with conjunctival congestion, bulbar conjunctival edema, eyelid swelling, follicular and papillary hyperplasia, changes in conjunctival color of the bulbar conjunctiva and dome, periocular cyanosis, gum-like hyperplasia of the corneal rim, and in severe cases, corneal epithelial infiltration and ulcer formation. The child also shows signs of nasal and skin allergy. Compared to adult allergic conjunctivitis, children with allergic conjunctivitis have more diagnostic significance in terms of edema and color changes of the bulbar conjunctiva and conjunctiva of the dome and the appearance of dark circles. There is also an imbalance between the signs and symptoms of overt conjunctivitis. In summary, an accurate diagnosis of allergy is important for treating patients symptomatically and potentially preventing or delaying the development of allergic disease. 1. A good clinical history includes a clear history of allergen exposure or, although the allergen is not clear, the onset of the disease in a specific environment, a specific season, a specific climate, etc.; a history of atopic dermatitis, allergic rhinitis or asthma and wheezing bronchitis also contributes to the diagnosis, especially for children with atypical allergic conjunctivitis diagnosis has decisive significance. 2, with clinical manifestations such as itchy eyes, red eyes, lacrimation, photophobia, lid conjunctival papillae and follicles, and changes in the color of the bulbar conjunctiva. 3.Anti-allergic treatment is effective. 4, cytological examination if necessary, eosinophils are significantly increased, but Abelson pointed out that the absence of eosinophils in the smear does not exclude allergic conjunctivitis, because the cells are located deep in the conjunctiva, Bonini et al. also found that the allergic reaction in the conjunctival stroma is more severe; positive results of skin tests, radioallergen adsorption tests and enzyme immunoassay for IgE levels in the serum help in the The diagnosis of conjunctivitis. Also, since asthma, allergic rhinitis, atopic dermatitis and allergic conjunctivitis are the more common allergic diseases in clinical practice, it is common to see allergic rhinitis with allergic conjunctivitis and asthma, or atopic dermatitis with allergic rhinitis, allergic conjunctivitis and asthma.