Itchy eyes with white filamentous discharge should first be considered to be caused by allergic conjunctivitis. Allergic conjunctivitis is a type of immune conjunctivitis, which is a hypersensitive immune response of the conjunctiva to external allergens. There are many types of allergens, such as pollen, protein components of microorganisms, animal dander, and feathers. The main symptom of allergic conjunctivitis is itching and other discomfort. Patients may also have pain, foreign body sensation, photophobia, burning sensation, and white mucousy discharge, and clinical examination of the lid conjunctiva may be congested with varying degrees of follicular and papillary hyperplasia. Treatment of allergic conjunctivitis includes removal of the allergen, cold compresses on the eyelids, and saline rinsing of the conjunctival sac. Anti-itch action can be achieved with sodium cromoglycate eye drops, panthenol eye drops, emetine eye drops, pralophine eye drops, and glucocorticoids, such as flomylone eye drops, which are used according to the patient’s symptoms. Immunosuppressive agents such as cyclosporine A or FK506 eye drops may be used in severe cases.