It is quite normal for children to get itchy eyes owing to they always rub their eyes with dirty hands, which make bacteria get into eyes easily and finally give rise to itchy eyes. Anyway, you shall make sure if she really got eye infection. So, you'd better take her to see a doctor.
Itchy eyes usually does not last long and can go away on its own a few minutes later, but sometimes it can last for hours, days or longer. Itchy eyes can be symptoms of allergies, under such case, you can apply cool compresses over your daughter's itchy eyes and ask her to take some medications named antihistamines in the meanwhile. But you should also be on the alert that your daughter is suffering from conjunctivitis or pinkeye, then you should take her to see a doctor as early as possible to determine the best course of treatment. You should warn your child of not rubbing her hands and of washing her hands often. Wish your daughter recover soon.
Children are easily to get allergic reaction from allergens of various resources, for example, food, air, dust, pollen or pet dander. It will cause sneezing, runny nose, eye itching. Normally children are tending to rub their eyes because of its itching. If they got allergens on their hands, then it would definitely make the infection as well as itching worse. You should have your child out of touch with any possible allergens. Keep her eyes and hands clean with mild soap. Wash her eyes with water to make sure the allergens out of eyes. Use an air purifier and humidifier. Air purifier can filter possible dusts and allergens while humidifier can add some moist to the air to relieve the itching and dryness. If you found her allergic reaction keep worsening, then contact her doctor at once. Some serious allergic reaction might cause breathing difficulty which could be very dangerous.