Unless she has had a "runny eyes and nose" since the day she was born, or unless something has significantly changed in her usual environment (carpet, pet, laundry or bath products); it is unlikely to be allergies.
It is more likely to be the typical cold or sniffles, especially if she attends day care or preschool with other children.
But to answer your question about allergies, yes. It is possible for a child that age to have allergies.
If her parents are concerned, they should ask your granddaughter's pediatrician to evaluate her condition and determine a course of action, if one is warranted.
