Well,allergies can cause crusty eyes.Do you know?Allergies can often cause eyes to water and then a crusty formation will be formed around your eyes.This can give rise to an eye infection quite easily.I know that your eyes may water once in a while,but remember not to rub or wipe them while watering.However,when the overproduction dries,a crust forms.But don't worry,it usually happens during your sleep,that is why when you try to open your eyes,you may find that a little difficult.And what you can do is to see a doctor in no time.However,if your allergy causes your eye to produce too much substance,you should take measures to control the allergens.If you are at home,you should keep the window to let fresh air in.Don't use air conditioner a lot,that is also one of the reasons you get allergic in your eyes.But don't worry too much,if your symptoms get worse and worse,the doctor will give you some medication.Just follow the doctor's advice.Best wishes to you!!!!!!!